-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 AxNn/H1LU/9mElbPs/yd3V0XpDKkjhliM4TpzB+/teIwPLBrHoLfPsB3/beRJwAv
 4oWVkUd2FbBk33qBLWz0rQ==

<SEC-DOCUMENT>0001104659-07-076169.txt : 20071022
<SEC-HEADER>0001104659-07-076169.hdr.sgml : 20071022
<ACCEPTANCE-DATETIME>20071022171716
ACCESSION NUMBER:		0001104659-07-076169
CONFORMED SUBMISSION TYPE:	8-A12G/A
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20071022
DATE AS OF CHANGE:		20071022

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AVANT IMMUNOTHERAPEUTICS INC
		CENTRAL INDEX KEY:			0000744218
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		IRS NUMBER:				133191702
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-A12G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15006
		FILM NUMBER:		071183727

	BUSINESS ADDRESS:	
		STREET 1:		119 FOURTH AVE
		CITY:			NEEDHAM
		STATE:			MA
		ZIP:			02494
		BUSINESS PHONE:		7814330771

	MAIL ADDRESS:	
		STREET 1:		119 FOURTH AVE
		CITY:			NEEDHAM
		STATE:			MA
		ZIP:			021942725

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	T CELL SCIENCES INC
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-A12G/A
<SEQUENCE>1
<FILENAME>a07-27173_78a12ga.htm
<DESCRIPTION>8-A12G/A
<TEXT>
<html>

<head>





</head>

<body lang="EN-US">

<div style="font-family:Times New Roman;">

<div style="border:none;border-top:double windowtext 6.0pt;padding:0in 0in 0in 0in;">

<p align="center" style="border:none;margin:0in 0in .0001pt;padding:0in;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

</div>

<p align="center" style="font-size:10.0pt;margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">SECURITIES AND EXCHANGE COMMISSION</font></b><b><br>
Washington, DC 20549</b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<div align="center" style="margin:0in 0in .0001pt;text-align:center;"><hr size="1" width="25%" noshade color="black" align="center"></div>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">Form 8-A/A</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">(Amendment
No.&nbsp;1)</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<div align="center" style="margin:0in 0in .0001pt;text-align:center;"><hr size="1" width="25%" noshade color="black" align="center"></div>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">FOR REGISTRATION OF CERTAIN CLASSES
OF SECURITIES PURSUANT TO<br>
SECTION<br>
12(b) OR (g)&nbsp;OF THE SECURITIES EXCHANGE ACT OF 1934</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">AVANT IMMUNOTHERAPEUTICS,&nbsp;INC.</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Exact name of registrant as
specified in charter) </font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<div align="center">

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Delaware</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">13-3191702</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(State or Other Jurisdiction<br>
  of Incorporation)</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(I.R.S.&nbsp;Employer<br>
  Identification&nbsp;No.)</font></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">119 Fourth Avenue<br>
  Needham, MA</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="bottom" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">02494-2725</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Address of Principal Executive Offices)</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Zip Code)</font></p>
  </td>
 </tr>
</table>

</div>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="font-size:10.0pt;margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">If this form relates to the registration of a class of
  securities pursuant to Section 12(b) of the Exchange Act and is effective
  pursuant to General Instruction A.(c), please check the following
  box.&nbsp;&nbsp;</font></b><b><font face="Wingdings" style="font-weight:bold;">o</font></b></p>
  </td>
  <td width="1%" valign="bottom" style="padding:0in .7pt 0in .7pt;width:1.84%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="font-size:10.0pt;margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">If this form relates to the registration of a class of
  securities pursuant to Section 12(g) of the Exchange Act and is effective
  pursuant to General Instruction A.(d), please check the following
  box.&nbsp;&nbsp;</font></b><b><font face="Wingdings" style="font-weight:bold;">x</font></b></p>
  </td>
 </tr>
</table>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<div align="center" style="margin:0in 0in .0001pt;text-align:center;"><hr size="1" width="25%" noshade color="black" align="center"></div>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Securities
Act registration statement file number to which this relates:</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Securities
to be registered pursuant to Section&nbsp;12(b) of the Act:<b> None</b></font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Securities
to be registered pursuant to Section&nbsp;12(g) of the Act:</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="48%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:48.08%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Title of Each Class</font></b><font size="1" style="font-size:8.0pt;"><br>
  <b>to be so Registered</b></font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.58%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:49.34%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Name of Each Exchange on Which</font></b><font size="1" style="font-size:8.0pt;"><br>
  <b>Each Class is to be Registered</b></font></p>
  </td>
 </tr>
 <tr>
  <td width="48%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:48.08%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Preferred Stock Purchase Rights</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.58%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:49.34%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">NASDAQ</font></b></p>
  </td>
 </tr>
</table>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Common
Stock, $0.001 par value (1)</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Title
of Class)</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="1" width="25%" noshade color="black" align="left"></div>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(1)
This amendment relates to the common stock, par value $0.01 per share, of the
registrant and associated rights to purchase the registrant&#146;s Series&nbsp;C-1
Junior Participating Cumulative Preferred Stock, par value $0.01 per share.</font></p>

<div style="border:none;border-bottom:double windowtext 6.0pt;padding:0in 0in 0in 0in;">

<p align="center" style="border:none;margin:0in 0in .0001pt;padding:0in;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

</div>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>

</div>
<!-- SEQ.=1,FOLIO='',FILE='C:\JMS\105467\07-27173-7\task2470390\27173-7-ba.htm',USER='105467',CD='Oct 23 02:32 2007' -->


<br clear="all" style="page-break-before:always;">


<div style="font-family:Times New Roman;">

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">This
Form 8-A/A amends and supplements the Registration Statement on Form 8-A filed
by AVANT Immunotherapeutics,&nbsp;Inc. (the &#147;Company&#148;), with the Securities and
Exchange Commission on November 8, 2004 (including the Exhibits thereto, the &#147;<u>Form
8-A</u>&#148;).&nbsp;Capitalized terms used without definition herein shall have the
meaning set forth in the Shareholder Rights Agreement dated November&nbsp;5,
2004, (the &#147;<u>Rights Agreement</u>&#148;) between the Company and EquiServe Trust
Company, N.A., as Rights Agent (the &#147;<u>Rights Agent</u>&#148;).</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="font-size:10.0pt;margin:0in 0in .0001pt;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;">Item&nbsp;1</font></u>.&nbsp;<u>Description
of Registrant&#146;s Securities to be Registered</u>.</p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Item&nbsp;1
of the Form 8-A is amended and supplemented by adding the following:</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Amendment to Rights Agreement</font></b></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Item 1. <i>Description
of Registrant&#146;s Securities to be Registered.</i></font></b></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">In
connection with the expected execution of the Agreement and Plan of Merger,
dated as of October 19, 2007 (as it may be amended or supplemented from time to
time, the &#147;<u>Merger Agreement</u>&#148;), among the Company, Celldex Therapeutics,
Inc. (&#147;<u>Celldex</u>&#148;) and Callisto Merger Corporation, a Delaware corporation
and a wholly-owned subsidiary of the Company (&#147;<u>Merger Sub</u>&#148;), on October
19, 2007, Computershare Trust Company, N.A, as Rights Agent, entered into
Amendment No.&nbsp;1 to the Rights Agreement, dated as of November 5, 2004 (the
&#147;<u>Amendment</u>&#148;). The Amendment provides that: (i)&nbsp;neither Merger Sub,
nor Celldex or any of their Affiliates and Associates, (as those terms are
defined in the Rights Agreement) either individually, collectively or in any
combination, will be deemed to be an &#147;Acquiring Person&#148;, a &#147;Beneficial Owner&#148;
or a &#147;Principal Party&#148; solely by virtue or as a result of the approval,
execution, delivery, adoption or performance of the Merger Agreement, the
commencement or consummation of the Merger, the issuance of shares of AVANT
Common Stock to Celldex stockholders in connection with the Merger. The filing
of a charter amendment with the Secretary of State of the State of Delaware in
connection with the Merger or any other transactions contemplated thereby,
(such actions described in this sentence, the &#147;<u>Permitted Events</u>&#148;) and
(ii)&nbsp;no &#147;Stock Acquisition Date&#148; or &#147;Distribution Date&#148; will be deemed to
have occurred solely by virtue or as a result of the public announcement of any
Permitted Event.</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">The
Amendment is attached hereto as an exhibit and is hereby incorporated by
reference.&nbsp;The foregoing description of the Amendment does not purport to
be complete and is qualified in its entirety by reference to the Amendment.</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Miscellaneous</font></b></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">The
foregoing description of the Rights Amendment does not purport to be complete
and is qualified in its entirety by reference to the Rights Agreement which is
incorporated herein by reference.</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Item 2&#151;<i>Exhibits. </i></font></b></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="7%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:7.66%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit&nbsp;No.</font></b></p>
  </td>
  <td width="4%" valign="bottom" style="padding:0in 0in 0in 0in;width:4.62%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="87%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:87.72%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Description</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="7%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:7.66%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">10.1</font></p>
  </td>
  <td width="4%" valign="bottom" style="padding:0in 0in 0in 0in;width:4.62%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="87%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:87.72%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Amendment
  No. 1 to Shareholder Rights Agreement dated November&nbsp;5, 2004, between
  the Company and Computershare Trust Company, N.A. (formerly EquiServe Trust
  Company, N.A.), as Rights Agent.</font></p>
  </td>
 </tr>
</table>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">SIGNATURE</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.25in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Pursuant to the requirements of Section&nbsp;12 of
the Securities Exchange Act of 1934, the registrant has duly caused this
registration statement to be signed on its behalf by the undersigned, thereto
duly authorized.</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>

</div>
<!-- SEQ.=1,FOLIO='2',FILE='C:\JMS\105467\07-27173-7\task2470390\27173-7-ba.htm',USER='105467',CD='Oct 23 02:32 2007' -->


<br clear="all" style="page-break-before:always;">


<div>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="50%" colspan="3" valign="top" style="padding:0in .7pt 0in .7pt;width:50.92%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">AVANT IMMUNOTHERAPEUTICS,&nbsp;INC.</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="50%" colspan="3" valign="top" style="padding:0in .7pt 0in .7pt;width:50.92%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Date:
  October 19, 2007</font></p>
  </td>
  <td width="5%" valign="top" style="padding:0in .7pt 0in .7pt;width:5.54%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>
  </td>
  <td width="31%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in .7pt 0in .7pt;width:31.4%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/&nbsp;&nbsp;Una
  S. Ryan</font></p>
  </td>
  <td width="13%" valign="top" style="padding:0in .7pt 0in .7pt;width:13.98%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="5%" valign="top" style="padding:0in .7pt 0in .7pt;width:5.54%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="31%" valign="top" style="padding:0in .7pt 0in .7pt;width:31.4%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="13%" valign="top" style="padding:0in .7pt 0in .7pt;width:13.98%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="5%" valign="top" style="padding:0in .7pt 0in .7pt;width:5.54%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="45%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:45.38%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Name:
  Una S. Ryan, Ph.D</font></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.08%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="5%" valign="top" style="padding:0in .7pt 0in .7pt;width:5.54%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="45%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:45.38%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Title:
  President and Chief Executive Officer</font></p>
  </td>
 </tr>
</table>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">EXHIBIT
INDEX </font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="8%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:8.74%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit&nbsp;No.</font></b></p>
  </td>
  <td width="3%" valign="bottom" style="padding:0in 0in 0in 0in;width:3.3%;">
  <p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="87%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:87.96%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Description</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="8%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:8.74%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">10.1</font></p>
  </td>
  <td width="3%" valign="bottom" style="padding:0in 0in 0in 0in;width:3.3%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="87%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:87.96%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Amendment
  No. 1 to Shareholder Rights Agreement dated November&nbsp;5, 2004, between
  the Company and Computershare Trust Company, N.A. (formerly EquiServe Trust
  Company, N.A.), as Rights Agent.</font></p>
  </td>
 </tr>
</table>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">3</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>

</div>
<!-- SEQ.=1,FOLIO='3',FILE='C:\JMS\105467\07-27173-7\task2470390\27173-7-ba.htm',USER='105467',CD='Oct 23 02:32 2007' -->


</body>

</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-10.1
<SEQUENCE>2
<FILENAME>a07-27173_7ex10d1.htm
<DESCRIPTION>EX-10.1
<TEXT>
<html>

<head>





</head>

<body lang="EN-US">

<div style="font-family:Times New Roman;">

<p align="right" style="margin:0in 0in .0001pt;text-align:right;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Exhibit
10.1</font></b></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="font-size:10.0pt;margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">FIRST
AMENDMENT TO THE </font></b><b><font style="font-weight:bold;">SHAREHOLDER</font>
RIGHTS AGREEMENT</b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">FIRST AMENDMENT, dated as
of October 19, 2007 (this &#147;<u>Amendment</u>&#148;), to the Shareholder Rights
Agreement, dated as of November 5, 2004 (the &#147;<u>Rights Agreement&#148;</u>), by and
between AVANT Immunotherapeutics, Inc., a Delaware corporation (the &#147;<u>Company&#148;</u>)
and Computershare Trust Company, N.A. (formerly EquiServe Trust Company, N.A.),
as rights agent (the &#147;<u>Rights Agent</u>&#148;). Terms used herein but not defined
shall have the meaning assigned to them in the Rights Agreement.</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">WHEREAS, the Company and
the Rights Agent have heretofore executed and entered into the Rights
Agreement;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">WHEREAS, the Company
proposes to enter into an Agreement and Plan of Merger (as it may be amended
from time to time, the &#147;<u>Merger Agreement</u>&#148;), among the Company, Celldex
Therapeutics, Inc. (&#147;<u>Celldex</u>&#148;) and Callisto Merger Corporation, a
Delaware corporation and a wholly-owned subsidiary of the Company (&#147;<u>Merger
Sub</u>&#148;), providing for the merger of Merger Sub with and into Celldex (the &#147;<u>Merger</u>&#148;),
with Celldex continuing as the surviving corporation and wholly-owned
subsidiary of the Company;</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">WHEREAS, pursuant to the Merger,
the Company will acquire all of the outstanding equity securities of Celldex by
way of merger of Merger Sub with and into Celldex and the Company will issue
shares of the Company&#146;s Common Stock, par value $.001 per share (the &#147;<u>AVANT
Common Stock</u>&#148;), to Celldex stockholders (and option holders) in
consideration for the Merger (the &#147;<u>Share Issuance</u>&#148;);</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">WHEREAS, the Board of Directors
of the Company (the &#147;<u>Board</u>&#148;) has determined, in connection with the
execution of the Merger Agreement, the execution thereof and the transactions
contemplated hereby, including, without limitation, the Merger and the Share
Issuance, from the application of the Rights Agreement, as set forth in this
Amendment;</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">WHEREAS, (i) Section 27
of the Rights Agreement provides that, so long as the Rights are not then
redeemable, the Company and the Rights Agent shall, if so directed by the
Board, supplement or amend any provision of the Rights Agreement without the
approval of any holders of certificates representing shares of Common Stock of
the Company (subject to limited exceptions that do not apply for purposes
hereof); (ii) pursuant to Section 27 of the Rights Agreement, an appropriate
officer of the Company has delivered a certificate to the Rights Agent stating
that the proposed supplements and amendments to the Rights Agreement set forth
in this Amendment are in compliance with Section 27 of the Rights Agreement;
and (iii)&#160; pursuant to the terms of the
Rights Agreement and in accordance with Section 27 thereof, the Board has
directed that the Rights Agreement should be amended and supplemented as set
forth in this Amendment prior to the execution of the Merger Agreement.</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>

</div>
<!-- SEQ.=1,FOLIO='',FILE='C:\JMS\105479\07-27173-7\task2469812\27173-7-ke.htm',USER='105479',CD='Oct 22 22:27 2007' -->


<br clear="all" style="page-break-before:always;">


<div style="font-family:Times New Roman;">

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">NOW, THEREFORE, in
consideration of the premises and the mutual agreements herein set forth, the
parties hereby agree as follows:</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">1. <u>Amendment to Rights
Agreement</u>.</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:1.0in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(a)&#160; The definition of &#147;<i>Acquiring
Person</i>&#148; in Section 1(a) of the Rights Agreement is amended by
inserting the following as a new paragraph at the end of such definition:</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="font-size:10.0pt;margin:0in 0in .0001pt .5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&#147;Further, notwithstanding
anything in this Agreement to the contrary, none of Celldex Therapeutics, Inc.,
a Delaware corporation (&#147;<i>Celldex</i>&#148;),
Callisto Merger Corporation, a Delaware corporation (&#147;<i>Merger Sub</i>&#148;)
or any of their respective Affiliates or Associates, either individually,
collectively or in any combination, shall be an &#147;Acquiring Person&#148;, &#147;Beneficial
Owner&#148; or &#147;Principal Party&#148; solely by virtue or as a result of the approval,
execution, delivery, adoption or performance of the Agreement and Plan of
Merger, dated as of October 19, 2007, among Celldex, Merger Sub and the Company
(as it may be amended or supplemented from time to time, the &#147;<i>Merger Agreement</i>&#148;) or the commencement or consummation of
the Merger (as such term is defined in the Merger Agreement), the issuance of
shares of AVANT Common Stock to Celldex stockholders </font>(and
option holders) in connection with the Merger (the &#147;<i>Issuance</i>&#148;)
or any other transactions contemplated thereby, (such actions described in this
sentence, the &#147;<i>Permitted Events</i>&#148;).&#148;</p>

<p style="margin:0in 0in .0001pt .5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:1.0in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(b)&#160; The definition of &#147;<i>Stock
Acquisition Date</i>&#148; in Section 1(jj) of the Rights Agreement is
deleted in its entirety and replaced with the following:</font></p>

<p style="margin:0in 0in .0001pt;text-indent:1.0in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt .5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&#147; &#145;<i>Stock
Acquisition Date&#146; </i>shall mean the date of the first public
announcement (which for purposes of this definition shall include, without
limitation, the issuance of a press release or the filing of a
publicly-available report or other document with the Securities and Exchange
Commission or any other governmental agency) by the Company, acting pursuant to
a resolution adopted by the Board of Directors of the Company, or by an
Acquiring Person, subject in each case to the last two paragraphs of Section
1(a), that an Acquiring Person has become such. Notwithstanding anything in
this Agreement to the contrary, a Stock Acquisition Date shall not be deemed to
have occurred solely by virtue or as a result of the public announcement of any
Permitted Event.&#148;</font></p>

<p style="margin:0in 0in .0001pt .5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt .5in;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(c)&#160; Section 3(a) of the Rights Agreement is
amended to add the following sentence at the end thereof:</font></p>

<p style="margin:0in 0in .0001pt .5in;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt .5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&#147;Notwithstanding anything
in this Agreement to the contrary, a Distribution Date shall not be deemed to
have occurred solely as the result of any Permitted Event.&#148;</font></p>

<p style="margin:0in 0in .0001pt .5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2. <u>Interpretation</u>.
The term &#147;<u>Agreement</u>&#148; as used in the Rights Agreement shall be deemed to
refer to the Rights Agreement as amended hereby.</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>

</div>
<!-- SEQ.=1,FOLIO='2',FILE='C:\JMS\105479\07-27173-7\task2469812\27173-7-ke.htm',USER='105479',CD='Oct 22 22:27 2007' -->


<br clear="all" style="page-break-before:always;">


<div>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">3. <u>Severability</u>.
If any term, provision, covenant or restriction of this Amendment is held by a
court of competent jurisdiction or other authority to be invalid, void or
unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Amendment, and of the Rights Agreement, shall remain in
full force and effect and shall in no way be affected, impaired or invalidated.</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4. <u>Waiver of Notice</u>.
The Rights Agent and the Company hereby waive any notice requirement under the
Rights Agreement pertaining to the matters covered by this Amendment.</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">5. <u>Effectiveness</u>.
This Amendment shall be deemed effective as of the date first written above. Except
as expressly amended herein, all other terms and conditions of the Rights
Agreement shall remain in full force and effect. Without limiting the foregoing,
the Rights Agent shall not be subject to, nor required to interpret or comply
with, or determine if any Person has complied with, the Merger Agreement even
though reference thereto may be made in this Amendment and the Rights
Agreement.</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">6.
<u>Governing Law</u>. This Amendment shall be deemed to be a contract made
under the laws of the State of Delaware, and for all purposes of this Amendment
shall be governed by and construed in accordance with the laws of such State
applicable to contracts made and to be performed entirely within such State. The
courts of the State of Delaware and of the United States of America located in
the State of Delaware (the &#147;Delaware Courts&#148;) shall have exclusive jurisdiction
over any litigation arising out of or relating to this Amendment and the
transactions contemplated hereby, and any Person commencing or otherwise
involved in any such litigation shall waive any objection to the laying of
venue of such litigation in the Delaware Courts and shall not plead or claim in
any Delaware Court that such litigation brought therein has been brought in an
inconvenient forum.</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">7. <u>Counterparts</u>.
This Amendment may be executed in any number of counterparts, each of which
shall be an original and all of which shall constitute one and the same
document.</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">IN WITNESS WHEREOF, the
parties have caused this Amendment to be duly executed as of the day and year
first above written.</font></p>

<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="27%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:27.3%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">ATTEST:</font></p>
  </td>
  <td width="23%" valign="top" style="padding:0in 0in 0in 0in;width:23.12%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="49%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:49.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">AVANT Immunotherapeutics, Inc.</font></p>
  </td>
 </tr>
 <tr>
  <td width="27%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:27.3%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="23%" valign="top" style="padding:0in 0in 0in 0in;width:23.12%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="49%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:49.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="27%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:27.3%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="23%" valign="top" style="padding:0in 0in 0in 0in;width:23.12%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="49%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:49.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.5%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>
  </td>
  <td width="16%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:16.76%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/ s/&nbsp;&nbsp;Una S.
  Ryan</font></p>
  </td>
  <td width="7%" valign="top" style="padding:0in 0in 0in 0in;width:7.04%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="23%" valign="top" style="padding:0in 0in 0in 0in;width:23.12%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.92%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>
  </td>
  <td width="18%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:18.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ Avery W. Catlin</font></p>
  </td>
  <td width="27%" valign="top" style="padding:0in 0in 0in 0in;width:27.08%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="27%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:27.3%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="23%" valign="top" style="padding:0in 0in 0in 0in;width:23.12%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.92%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="45%" colspan="2" valign="top" style="padding:0in 0in 0in 0in;width:45.66%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Name: Avery W. Catlin</font></p>
  </td>
 </tr>
 <tr>
  <td width="27%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:27.3%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="23%" valign="top" style="padding:0in 0in 0in 0in;width:23.12%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.92%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="45%" colspan="2" valign="top" style="padding:0in 0in 0in 0in;width:45.66%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Title:&nbsp;&nbsp;&nbsp;Chief Financial Officer</font></p>
  </td>
 </tr>
 <tr height="0">
  <td width="26" style="border:none;"></td>
  <td width="125" style="border:none;"></td>
  <td width="53" style="border:none;"></td>
  <td width="173" style="border:none;"></td>
  <td width="29" style="border:none;"></td>
  <td width="139" style="border:none;"></td>
  <td width="203" style="border:none;"></td>
 </tr>
</table>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">3</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>

</div>
<!-- SEQ.=1,FOLIO='3',FILE='C:\JMS\105479\07-27173-7\task2469812\27173-7-ke.htm',USER='105479',CD='Oct 22 22:27 2007' -->


<br clear="all" style="page-break-before:always;">


<div>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="25%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:25.02%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">ATTEST:</font></p>
  </td>
  <td width="25%" valign="top" style="padding:0in 0in 0in 0in;width:25.0%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="49%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:49.98%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">COMPUTERSHARE TRUST
  COMPANY, N.A.,</font></p>
  </td>
 </tr>
 <tr>
  <td width="25%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:25.02%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="25%" valign="top" style="padding:0in 0in 0in 0in;width:25.0%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="49%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:49.98%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">as Rights Agent</font></p>
  </td>
 </tr>
 <tr>
  <td width="25%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:25.02%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="25%" valign="top" style="padding:0in 0in 0in 0in;width:25.0%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="46%" colspan="2" valign="top" style="padding:0in 0in 0in 0in;width:46.4%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="25%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:25.02%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="25%" valign="top" style="padding:0in 0in 0in 0in;width:25.0%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="46%" colspan="2" valign="top" style="padding:0in 0in 0in 0in;width:46.4%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.16%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>
  </td>
  <td width="13%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:13.34%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ Jeff Seiders</font></p>
  </td>
  <td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.52%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="25%" valign="top" style="padding:0in 0in 0in 0in;width:25.0%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>
  </td>
  <td width="24%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:24.6%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ Katherine S.
  Anderson</font></p>
  </td>
  <td width="21%" valign="top" style="padding:0in 0in 0in 0in;width:21.8%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="25%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:25.02%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="25%" valign="top" style="padding:0in 0in 0in 0in;width:25.0%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="46%" colspan="2" valign="top" style="padding:0in 0in 0in 0in;width:46.4%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Name: Katherine S.
  Anderson</font></p>
  </td>
 </tr>
 <tr>
  <td width="25%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:25.02%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="25%" valign="top" style="padding:0in 0in 0in 0in;width:25.0%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in 0in 0in 0in;width:3.58%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="46%" colspan="2" valign="top" style="padding:0in 0in 0in 0in;width:46.4%;">
  <p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Title: Managing
  Director</font></p>
  </td>
 </tr>
 <tr height="0">
  <td width="24" style="border:none;"></td>
  <td width="100" style="border:none;"></td>
  <td width="64" style="border:none;"></td>
  <td width="187" style="border:none;"></td>
  <td width="27" style="border:none;"></td>
  <td width="184" style="border:none;"></td>
  <td width="163" style="border:none;"></td>
 </tr>
</table>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4</font></p>

<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>

</div>
<!-- SEQ.=1,FOLIO='4',FILE='C:\JMS\105479\07-27173-7\task2469812\27173-7-ke.htm',USER='105479',CD='Oct 22 22:27 2007' -->


</body>

</html>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
