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                                                                    Exhibit 10.6







                        ADVANCED BIOTHERAPY COMPANY, INC.


                CONVERTIBLE SUBORDINATED DEBT PURCHASE AGREEMENT

                                  June 29, 2000


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                        ADVANCED BIOTHERAPY COMPANY, INC.

                CONVERTIBLE SUBORDINATED DEBT PURCHASE AGREEMENT

       This Convertible Subordinated Debt Purchase Agreement (the "AGREEMENT")
is made as of the 29th day of June 2000, by and between Advanced Biotherapy
Company, Inc., a Nevada corporation (the "COMPANY"), and each of the investors
listed on EXHIBIT A attached hereto (each a "PURCHASER" and together the
"PURCHASERS").

                                    RECITALS

       Simultaneously with execution hereof, the Company, the Purchasers and the
other parties named therein are entering an Investor Rights Agreement (the
"Investor Rights Agreement").

       The parties hereby agree as follows:

       1.     PURCHASE AND SALE OF CONVERTIBLE SUBORDINATED DEBT.

              1.1    SALE AND ISSUANCE OF CONVERTIBLE SUBORDINATED DEBT.

                     Subject to the terms and conditions of this Agreement, each
Purchaser agrees to purchase at the Closing and the Company agrees to sell and
issue to each Purchaser at the Closing that aggregate principal amount of the
Company's 10% Convertible Subordinated Debt due September 30, 2004 ("Convertible
Subordinated Debt"), set forth opposite each such Purchaser's name on EXHIBIT A
attached hereto at a purchase price equal to the face amount thereof purchased
by such Purchaser. The debt instruments issued to the Purchaser pursuant to this
Agreement shall be hereinafter referred to as the "DEBT INSTRUMENTS" and the
Convertible Subordinated Debt evidenced thereby as the "DEBT." The Company's
agreement with each of the Purchasers hereunder is a separate agreement, the
obligations of each of the Purchasers hereunder are several and not joint, and
the sale of the Debt to each of the Purchasers is a separate transaction. The
Debt is convertible to shares of the Company's common stock, $.001 par value, in
accordance with the applicable provisions set forth in the Debt Instruments
evidencing the Debt, the form of which instruments is set forth in EXHIBIT B
attached hereto. Shares of capital stock issued to the Purchaser pursuant to the
Debt Instruments conversion provisions are referred to hereafter as the "STOCK".

              1.2    CLOSING; DELIVERY.

                     (a) CLOSING. The initial purchase and sale of the Debt
shall take place at the offices of the Company, 6355 Topanga Canyon Boulevard,
Suite 510, Woodland Hills, California 91367 at 10:00 a.m. on July 7, 2000, or at
such other time and place as the Company and the Purchasers mutually agree
orally or in writing (which time and place are designated as


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the "INITIAL CLOSING"). At the Initial Closing and each Closing (as defined
below), the Company shall deliver to each Purchaser a Debt Instrument
representing the Debt that such Purchaser is purchasing against payment of the
purchase price therefor by check, wire transfer, cancellation of indebtedness or
any combination thereof. In the event that payment by a Purchaser is made, in
whole or in part, by cancellation of indebtedness, then such Purchaser shall
surrender to the Company for cancellation at such Initial Closing or Closing any
evidence of such indebtedness or shall execute an instrument of cancellation in
form and substance acceptable to the Company.

                     (b) SUBSEQUENT SALE OF DEBT. The Company may sell up to the
balance of the authorized aggregate principal amount of Two Million Dollars
($2,000,000) of Debt not sold at the Initial Closing to such Purchasers as it
shall select, at a price not less than the face amount thereof, provided the
agreement for sale is executed not later than one hundred fifty (150) days
immediately following the date of the Initial Closing. Any such Purchaser shall
become a party to this Agreement, and shall have the rights and obligations
hereunder, by executing and delivering to the Company an additional counterpart
signature page to this Agreement. In the event there is more than one closing,
the term "Closing" shall apply to the Initial Closing and each such other
closing unless otherwise specified.

       2. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company hereby
represents and warrants to each Purchaser that, except as set forth on a
Schedule of Exceptions attached hereto as EXHIBIT C, which exceptions shall be
deemed to be representations and warranties as if made hereunder:

              2.1 ORGANIZATION, GOOD STANDING AND QUALIFICATION. The Company is
a corporation duly organized, validly existing and in good standing under the
laws of the State of Nevada and has all requisite corporate power and authority
to carry on its business. The Company is duly qualified to transact business and
is in good standing in each jurisdiction in which the failure so to qualify
would have a material adverse effect on its business or properties.

              2.2 CAPITALIZATION. The authorized capital of the Company
consists, or will consist, immediately prior to the Closing, of:

                     (a) 50,000,000 shares of capital stock, 39,398,265 shares
of which are issued and outstanding immediately prior to the Closing. All of the
outstanding shares of capital stock have been duly authorized, validly issued,
fully paid and are nonassessable, issued in compliance with all applicable
federal and state securities laws.

                     (b) Options to purchase 2,877,953 shares of Company Stock
have been granted and are currently outstanding; warrants to purchase 4,685,135
shares of Company Stock have been granted and are currently outstanding.


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                     (c) Except as disclosed pursuant to Section 6.7 and except
for outstanding options and warrants described in Section 2.2(b) above or as
contemplated by this Agreement, there are no outstanding options, warrants,
rights (including conversion or preemptive rights and rights of first refusal or
similar rights) or agreements, orally or in writing, for the purchase or
acquisition from the Company of any shares of its capital stock.

              2.3 SUBSIDIARIES. The Company does not currently own or control,
directly or indirectly, any interest in any other corporation, association, or
other business entity, and is not a participant in any joint venture or
partnership.

              2.4 AUTHORIZATION. All corporate action on the part of the
Company, its officers, directors and stockholders necessary for the
authorization, execution and delivery of this Agreement, the performance of all
obligations of the Company hereunder and the authorization, issuance and
delivery of the Debt has been taken or will be taken prior to the Closing, and
this Agreement constitutes the valid and legally binding obligation of the
Company, enforceable against the Company in accordance with their terms except
(i) as limited by applicable bankruptcy, insolvency, reorganization, moratorium,
fraudulent conveyance, and other laws of general application affecting
enforcement of creditors' rights generally, as limited by laws relating to the
availability of specific performance, injunctive relief, or other equitable
remedies, or (ii) to the extent any indemnification provisions may be limited by
applicable federal or state securities laws.

              2.5 VALID ISSUANCE OF DEBT AND STOCK. The Debt that is being
issued to the Purchasers hereunder, when issued, sold and delivered in
accordance with the terms hereof for the consideration expressed herein, will be
duly and validly issued and free of restrictions on transfer other than
restrictions on transfer under this Agreement, the Debt Instrument and the
Investor Rights Agreement and applicable state and federal and securities laws.
Based in part upon the representations of the Purchasers in this Agreement and
subject to the provisions of Section 2.6 below, the Debt will be issued in
compliance with all applicable federal and state securities laws. The underlying
Stock to be issued to the Purchasers hereunder, when issued and then, sold and
delivered in accordance with the terms hereof for the consideration expressed
herein and therein, will be duly and validly issued, fully paid and
nonassessasble and free of restrictions on transfer other than restrictions on
transfer under this Agreement, the Debt Instruments, the Investor Rights
Agreement and applicable state and federal securities laws. Based in part upon
the representations of the Purchasers in this Agreement and subject to the
provisions of Section 2.6 below, the Stock will be issued in compliance with all
applicable federal and state securities laws.

              2.6 GOVERNMENTAL CONSENTS. No consent, approval, order or
authorization of, or registration, qualification, designation, declaration or
filing with, any federal, state or local governmental authority on the part of
the Company is required in connection with the consummation of the transactions
contemplated by this Agreement, except for filings pursuant to


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applicable state securities laws and Regulation D of the Securities Act of 1933,
as amended (the "SECURITIES ACT") or, as provided in the Investor Rights
Agreement.

              2.7 LITIGATION. There is no action, suit, proceeding or
investigation pending or, to the Company's knowledge, currently threatened
against the Company that questions the validity of this Agreement or the right
of the Company to enter into them, or to consummate the transactions
contemplated hereby or thereby, or that might result, either individually or in
the aggregate, in any material adverse changes in the assets, condition or
affairs of the Company, financially or otherwise, or any change in the current
equity ownership of the Company, nor is the Company aware that there is any
basis for the foregoing. The Company is not a party or subject to the provisions
of any order, writ, injunction, judgment or decree of any court or government
agency or instrumentality. There is no action, suit, proceeding or investigation
by the Company currently pending or which the Company intends to initiate.

              2.8 INTELLECTUAL PROPERTY. To the Company's knowledge, the Company
owns or possesses sufficient legal rights to all trademarks, service marks,
tradenames, and, to its knowledge, all patents, copyrights, trade secrets,
licenses, information and proprietary rights and processes necessary for its
business without any conflict with, or infringement of, the rights of others.
There are no outstanding options, licenses or agreements of any kind relating to
the foregoing, nor is the Company bound by or a party to any options, licenses
or agreements of any kind with respect to the patents, trademarks, servicemarks,
tradenames, copyrights, trade secrets, licenses, information, proprietary rights
and processes of any other person or entity. The Company has not received any
communications alleging that the Company has violated or, by conducting its
business, would violate any of the patents, trademarks, service marks,
tradenames, copyrights, trade secrets or other proprietary rights or processes
of any other person or entity. The Company is not aware that any of its
employees is obligated under any contract (including licenses, covenants or
commitments of any nature) or other agreement, or subject to any judgment,
decree or order of any court or administrative agency, that would interfere with
the use of such employee's best efforts to promote the interest of the Company
or that would conflict with the Company's business. Neither the execution or
delivery of this Agreement, nor the carrying on of the Company's business by the
employees of the Company, nor the conduct of the Company's business as proposed,
will, to the Company's knowledge, conflict with or result in a breach of the
terms, conditions, or provisions of, or constitute a default under, any
contract, covenant or instrument under which any such employee is now obligated.
The Company does not believe it is or will be necessary to use any inventions of
any of its employees (or persons it currently intends to hire) made prior to or
outside the scope of their employment by the Company.

              2.9 COMPLIANCE WITH OTHER INSTRUMENTS.

                     (a) The Company is not in violation or default of any
provisions of its articles of incorporation or of any instrument, judgment,
order, writ, decree or contract to which


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it is a party or by which it is bound or, to its knowledge, of any provision of
federal or state statute, rule or regulation applicable to the Company. The
execution, delivery and performance of this Agreement and the consummation of
the transactions contemplated hereby will not result in any such violation or be
in conflict with or constitute, with or without the passage of time and giving
of notice, either a default under any such provision, instrument, judgment,
order, writ, decree or contract or an event which results in the creation of any
lien, charge or encumbrance upon any assets of the Company, or the suspension,
revocation, impairment, forfeiture or nonrenewal of any material permit,
license, authorization applicable to the Company, its business or operations or
any of its assets or properties, which suspension, revocation, impairment,
forfeiture or nonrenewal will have a material adverse effect on the Company's
business and operations.

                     (b) To its knowledge, the Company has avoided every
condition, and has not performed any act, the occurrence of which would result
in the Company's loss of any right granted under any license, distribution
agreement or other agreement.

              2.10 AGREEMENTS; ACTION.

                     (a) There are no agreements, understandings or proposed
transactions between the Company and any of its officers, directors, affiliates,
or any affiliate thereof.

                     (b) Except for agreements explicitly contemplated by this
Agreement, there are no agreements, understandings, instruments, contracts or
proposed transactions to which the Company is a party or by which it is bound
that involve (i) obligations (contingent or otherwise) of, or payments to, the
Company in excess of $50,000, (ii) the license of any patent, copyright, trade
secret or other proprietary right to or from the Company, or (iii) the grant of
rights to manufacture, produce, assemble, license, market, or sell its products
to any other person or affect the Company's exclusive right to develop,
manufacture, assemble, distribute, market or sell its products.

                     (c) Except for agreements explicitly contemplated by this
Agreement, the Company has not (i) declared or paid any dividends, or authorized
or made any distribution upon or with respect to any class or series of its
capital stock, (ii) incurred any indebtedness for money borrowed or incurred any
other liabilities individually in excess of $50,000 or in excess of $100,000 in
the aggregate, (iii) made any loans or advances to any person, other than
ordinary advances for travel expenses, or (iv) sold, exchanged or otherwise
disposed of any of its assets or rights, other than the sale of its inventory in
the ordinary course of business.

                     (d) For the purposes of subsections (b) and (c) above, the
indebtedness, liabilities, agreements, understandings, instruments, contracts
and proposed transactions involving the same person or entity shall be
aggregated for the purpose of meeting the individual minimum dollar amounts with
such subsections.


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                     (e) The Company is not a party to and is not bound by any
contract, agreement or instrument, or subject to any restriction under its
articles of incorporation or bylaws, that adversely affects its business, its
properties or its financial condition.

              2.11 DISCLOSURE. The Company has fully provided the Purchasers
with all information requested by the Purchasers in connection with their
decisions to acquire the Debt including all information that the Company
believes is reasonably necessary to enable the Purchasers to make such a
decision. To the Company's knowledge, no representation or warranty of the
Company contained in this Agreement and the exhibits attached hereto, any
certificate furnished or to be furnished to Purchasers at the Closing, or any
other document (when read together) contain any untrue statement of a material
fact, nor, to the Company's knowledge, omit to state a material fact necessary
in order to make the statements contained herein or therein not misleading in
light of the circumstances under which they were made. To the Company's
knowledge, there are no facts which (individually or in the aggregate)
materially adversely affect the business, assets, liabilities, financial
condition or operations of the Company that have not been set forth in this
Agreement, the exhibits hereto or in other documents delivered to the Purchasers
or their attorneys or agents in connection herewith. For purposes of this
Agreement, the Company shall be deemed to have "knowledge" if any director or
officer of the Company has actual knowledge of a particular fact or other
matter. As of the date of the Agreement, the Company is current as to its
periodic reporting requirements under the Securities Exchange Act of 1934, as
amended.

              2.12 NO CONFLICT OF INTEREST. The Company is not indebted,
directly or indirectly, to (i) any of its officers or directors or to their
respective spouses or children, in any amount whatsoever other than in
connection with expenses or advances of expenses incurred in the ordinary course
of business or relocation expenses of employees and (ii) any affiliates of the
Company. To the Company's knowledge, none of the Company's officers or directors
are, directly or indirectly, indebted to the Company (other than in connection
with purchases of the Company's stock) or have any direct or indirect ownership
interest in any firm or corporation with which the Company is affiliated or with
which the Company has a business relationship, or any firm or corporation which
competes with the Company except that officers and directors of the Company may
own stock in any publicly traded companies that may compete with the Company. To
the Company's knowledge, none of the Company's officers or directors are,
directly or indirectly, interested in any material contract with the Company.
The Company is not a guarantor or indemnitor of any indebtedness of any other
person, firm or corporation.

              2.13 RIGHTS OF REGISTRATION AND VOTING RIGHTS. Except for
agreements explicitly contemplated by this Agreement, the Company has not
granted or agreed to grant any registration rights, including piggyback rights,
to any person or entity. To the Company's knowledge, no stockholder of the
Company has entered into any agreements with respect to the voting of capital
shares of the Company.


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              2.14 PRIVATE PLACEMENT. Subject in part to the truth and accuracy
of the Purchasers' representations set forth in this Agreement, the offer, sale
and issuance of the Debt as contemplated by this Agreement is exempt from the
registration requirements of the Securities Act.

              2.15 TITLE TO PROPERTY AND ASSETS. The Company owns its property
and assets free and clear of all mortgages, liens, loans and encumbrances,
except such encumbrances and liens which arise in the ordinary course of
business and do not materially impair the Company's ownership or use of such
property or assets. With respect to the property and assets it leases, the
Company is in compliance with such leases and, to its knowledge, holds a valid
leasehold interest free of any liens, claims or encumbrances.

              2.16 EMPLOYEE BENEFIT PLAN. The Company does not have any Employee
Benefit Plan as defined in the Employee Retirement Income Security Act of 1974.

              2.17 TAX RETURNS AND PAYMENTS. The Company has filed all tax
returns and reports as required by law. These returns and reports are true and
correct in all material respects. The Company has paid all taxes and other
assessments due. The Company has never had any tax deficiency proposed or
assessed against it and has not executed any waiver of any statute of
limitations on the assessment or collection of any tax or governmental charge.
None of the Company's federal income tax returns and none of its state income or
franchise tax or sales or use tax returns have ever been audited by governmental
authorities. The Company has not incurred any taxes, assessments or governmental
charges other than in the ordinary course of business and the Company has made
adequate provisions on its books or accounts for all taxes, assessments and
governmental charges with respect to its business, properties and operations for
such period. The Company has withheld or collected from each payment made to
each of its employees, the amount of all taxes (including, but not limited to,
federal income taxes, Federal Insurance Contribution Act taxes and Federal
Unemployment Tax Act taxes) required to be withheld or collected therefrom, and
has paid the same to the proper tax receiving officers or authorized
depositories.

              2.18 LABOR AGREEMENTS AND ACTIONS. The Company is not bound by or
subject to (and none of its assets or properties is bound by or subject to) any
written or oral, express or implied, contract, commitment or arrangement with
any labor union, and no labor union has requested or, to the knowledge of the
Company, has sought to represent any of the employees, representatives or agents
of the Company. There is no strike or other labor dispute involving the Company
pending, or to the knowledge of the Company threatened, which could have a
material adverse effect on the assets, properties, financial condition,
operating results, or business of the Company, nor is the Company aware of any
labor organization activity involving its employees. The employment of each
officer and employee of the Company is terminable at the will of the Company. To
its knowledge, the Company has complied in all material respects with all


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applicable state and federal equal employment opportunity laws and with other
laws related to employment. The Company is not a party to or bound to any
currently effective employment contract, deferred compensation agreement, bonus
plan, incentive plan, profit sharing plan, retirement agreement or other
employee compensation agreement.

              2.19 CONFIDENTIAL INFORMATION AND INVENTION ASSIGNMENT AGREEMENTS.
Each employee, consultant and officer of the Company has (or will have) executed
an agreement with the Company as of the Initial Closing regarding
confidentiality and proprietary information substantially in the form or forms
delivered to the counsel for the Purchasers. The Company is not aware that any
of its employees or consultants is in violation thereof, and the Company will
use its best efforts to prevent any such violation. All consultants to or
vendors of the Company with access to confidential information of the Company
are parties to a written agreement substantially in the form or forms provided
to counsel for the Purchasers under which, among other things, each such
consultant or vendor is obligated to maintain the confidentiality of
confidential information of the Company. The Company is not aware that any of
its consultants or vendors are in violation thereof, and the Company will use
its best efforts to prevent any such violation.

              2.20 PERMITS. The Company has all franchises, permits, licenses
and any similar authority necessary for the conduct of its business, the lack of
which could materially and adversely affect the business, properties, prospects,
or financial condition of the Company. The Company is not in default in any
material respect under any of such franchises, permits, licenses or other
similar authority.

              2.21 CORPORATE DOCUMENTS. The articles of incorporation and bylaws
of the Company are in the form made available to counsel for the Purchasers. The
copy of the minute books of the Company made available to the Purchasers'
counsel contains minutes of all meetings of directors and stockholders and all
actions by written consent without a meeting by the directors and stockholders
since the date of incorporation and reflects all actions by the directors (and
any committee of directors) and stockholders.

              2.22 SIGNIFICANT CUSTOMERS AND SUPPLIERS. No major customer or
supplier as of the date hereof has materially reduced or threatened to terminate
or materially reduce its purchases from or provision of products or services to
the Company, as the case may be.

              2.23 REAL PROPERTY HOLDING COMPANY. The Company is not a real
property holding company within the meaning of Section 897 of the Internal
Revenue Code of 1986, as amended (the "Code").

              2.24 MANUFACTURING AND MARKETING RIGHTS. The Company has not
granted rights to manufacture, produce, assemble, lease, market or sell its
products to any other person

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and is not bound by any agreement that affects the Company's exclusive right to
develop, manufacture, assemble, distribute market or sell its products.

       3. REPRESENTATIONS AND WARRANTIES OF THE PURCHASERS. Each Purchaser
hereby severally represents and warrants to the Company that:

              3.1 AUTHORIZATION. Such Purchaser has full power and authority to
enter into this Agreement. This Agreement constitutes the valid and legally
binding obligation of the Purchaser, enforceable in accordance with its terms,
except (a) as limited by applicable bankruptcy, insolvency, reorganization,
moratorium, fraudulent conveyance, and any other laws of general application
affecting enforcement of creditors' rights generally, and as limited by laws
relating to the availability of a specific performance, injunctive relief, or
other equitable remedies, or (b ) to the extent any indemnification provisions
may be limited by applicable federal or state securities laws.

              3.2 PURCHASE ENTIRELY FOR OWN ACCOUNT. This Agreement is made with
the Purchaser in reliance upon the Purchaser's representation to the Company,
which by the Purchaser's execution of this Agreement, the Purchaser hereby
confirms, that the Debt and underlying Stock to be acquired by the Purchaser
will be acquired for investment for the Purchaser's own account, not as a
nominee or agent, and not with a view to the resale or distribution of any part
thereof, and that the Purchaser has no present intention of selling, granting
any participation in, or otherwise distributing the same. By executing this
Agreement, the Purchaser further represents that the Purchaser does not
presently have any contract, undertaking, agreement or arrangement with any
person to sell, transfer or grant participations to such person or to any third
person, with respect to any of the Debt or the underlying Stock. The Purchaser
has not been formed for the specific purpose of acquiring the Debt or the
underlying Stock.

              3.3 DISCLOSURE OF INFORMATION. The Purchaser has had an
opportunity to discuss the Company's business, management, financial affairs and
the terms and conditions of the offering of the Debt with the Company's
management as such Purchaser has requested. The Purchaser understands that such
discussions were intended to describe the aspects of the Company's business
which it believes to be material but were not a thorough or exhaustive
description. The Purchaser acknowledges having had full access to the Company's
Annual Report on Form 10-KSB/A filed May 4, 2000, for the year ended December
31, 1999 ("Annual Report") and the Company's Quarterly Report on Form 10-QSB
filed May 15, 2000, for the quarter ended March 31, 2000 ("Quarterly Report" and
together with the Annual Report, the "SEC Reports") as filed with the Securities
and Exchange Commission, as well as the Company's Notice and Proxy Statement
(preliminary and/or final) for the Company's stockholders meeting scheduled for
August 24, 2000, as filed with the Securities and Exchange Commission. The
Purchaser understands and agrees that such SEC Reports do not reflect any events
subsequent to March 31, 2000.


<PAGE>

              3.4 EXCLUSIVE RELIANCE. In deciding whether to acquire the Debt,
the Purchaser has relied exclusively upon (i) consultations with the Purchaser's
respective legal, financial and tax advisors, (ii) the representations and
warranties of the Company set forth in this Agreement, (iii) the Debt
Instrument, (iv) the Investor Rights Agreement and (v) the additional
information concerning the Company set forth in the SEC Reports, including the
exhibits thereto.

              3.5 RESTRICTED SECURITIES. The Purchaser understands that the Debt
and the Stock have not been, and the Debt and, except as provided in the
Investor Rights Agreement, the Stock will not be, registered under the
Securities Act or any state or other jurisdiction's securities laws, by reason
of a specific exemption from the registration provisions of the Securities Act
and qualification provisions of applicable state securities laws, which depends
upon, among other things, the bona fide nature of the investment intent and the
accuracy of the Purchaser's representations as expressed herein. The Purchaser
understands that the Debt and the Stock are "restricted securities" under
applicable federal and state securities laws and that, pursuant to these laws,
the Purchaser must hold the Debt indefinitely unless it is registered, and the
Stock until it is registered pursuant to the Investor Rights Agreement, with the
Securities and Exchange Commission and qualified by state authorities, or an
exemption from such registration and qualification requirements is available.
The Purchaser acknowledges that the Company has no obligation to register or
qualify the Debt for resale. The Purchaser further acknowledges that if an
exemption from registration or qualification is available, it may be conditioned
on various requirements including, but not limited to, the time and manner of
sale, the holding period for the Debt and the Stock, and on requirements
relating to the Company which are outside of the Purchaser's control, and which
the Company is under no obligation and may not be able to satisfy. The Purchaser
acknowledges that any registration rights relating to the Stock into which the
Debt may be converted (in accordance with its terms) are set forth in the
Investor Rights Agreement.

              3.6 DEBT. The Purchaser understands that the principal amount of
the Debt is subject to payment, in whole or in part, at any time and from time
to time prior to conversion, at the option of the Company and further is subject
to mandatory conversion, in whole or in part, in both cases upon the terms and
conditions set forth in the Debt Instruments.

              3.7 LEGENDS. The Purchaser understands that the Debt Instruments
evidencing the Debt and the certificates representing any Stock issued upon
conversion of the Debt, subject to the provisions of the Investor Rights
Agreement, may bear one or all of the following legends, or one substantially
similar thereto:

                     (a) "NEITHER THIS DEBT INSTRUMENT NOR ANY SECURITIES INTO
WHICH IT IS CONVERTIBLE HAS BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, OR
ANY APPLICABLE SECURITIES LAW OF ANY JURISDICTION AND IS A "RESTRICTED SECURITY"
AS THAT TERM IS DEFINED IN


<PAGE>

RULE 144 UNDER THE SECURITIES ACT AND HAS BEEN ACQUIRED FOR INVESTMENT AND NOT
WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF. THIS
DEBT INSTRUMENT AND THE SECURITIES INTO WHICH IT IS CONVERTIBLE MAY NOT BE
TRANSFERRED UNTIL (i) A REGISTRATION STATEMENT UNDER SUCH SECURITIES ACT OR SUCH
APPLICABLE SECURITIES LAWS SHALL HAVE BECOME EFFECTIVE WITH REGARD THERETO, OR
(ii) IN THE OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY REGISTRATION UNDER SUCH
SECURITIES ACT OR SUCH APPLICABLE SECURITIES LAWS IS NOT REQUIRED IN CONNECTION
WITH SUCH PROPOSED TRANSFER."

                     (b) Any legend required by the blue sky laws of any state
to the extent such laws are applicable to the shares represented by the
certificate so legended.

              3.8 INVESTMENT.

                     (a) If the Purchaser is an individual, he is at least 21
years of age, a citizen of the country and a bona fide resident and domiciliary
(not a temporary or transient resident) of the state indicated on the signature
page hereto, and he has no present intention of becoming a resident of any other
state or jurisdiction;

                     (b) The Purchaser has such knowledge and experience in
financial and business matters as to be capable of evaluating the risks of an
investment in the Debt and the underlying Stock and understands that (i) this
investment is suitable only for an investor who is able to bear the economic
consequences of losing its entire investment, (ii) the Company is a development
stage company with no operating revenue, (iii) an investment in the Debt and the
underlying Stock is a speculative investment which involves a high degree of
risk of loss by the Purchaser of his or its investment therein, and (iv) there
are substantial restrictions on the transferability of the Debt and the
underlying Stock.

              3.9 ACCREDITED INVESTOR. The Purchaser is an accredited investor
as defined in Rule 501(a) of Regulation D promulgated under the Securities Act.

              3.10 FOREIGN INVESTORS. If the Purchaser is not a United States
person (as defined by Section 7701(a)(30) of the Code), such Purchaser hereby
represents that it has satisfied itself as to the full observance of the laws of
its jurisdiction in connection with any invitation to subscribe for the Debt and
the underlying Stock or any use of this Agreement, including (i) the legal
requirements within its jurisdiction for the purchase of the Debt and the
underlying Stock, (ii) any foreign exchange restrictions applicable to such
purchase, (iii) any governmental or other consents that may need to be obtained,
and (iv) the income tax and other tax consequences, if any, that may be relevant
to the purchase, holding, redemption, sale, or transfer of the Debt and the
underlying Stock. Such Purchaser's subscription and payment for and continued
beneficial ownership of the Debt and the underlying Stock, will not violate any
applicable securities or other laws of the Purchaser's jurisdiction.


<PAGE>

       4. CONDITIONS OF THE PURCHASERS' OBLIGATIONS AT CLOSING. The obligations
of each Purchaser to the Company under this Agreement are subject to the
fulfillment, on or before the Closing, of each of the following conditions,
unless otherwise waived:

              4.1 REPRESENTATIONS AND WARRANTIES. The representations and
warranties of the Company contained in Section 2 shall be true and correct in
all material respects on and as of the Closing with the same effect as though
such representations and warranties had been made on and as of the date of the
Closing.

              4.2 PERFORMANCE. The Company shall have performed and complied
with all covenants, agreements, obligations and conditions contained in this
Agreement that are required to be performed or complied with by it on or before
the Closing.

              4.3 COMPLIANCE CERTIFICATE. The President of the Company shall
deliver to the Purchasers at the Closing a certificate certifying that the
conditions specified in Sections 4.1 and 4.2 have been fulfilled.

              4.4 INVESTOR RIGHTS AGREEMENT. The Company and the other parties
thereto other than Purchaser shall have duly executed and delivered the Investor
Rights Agreement to the Purchaser.

              4.5 QUALIFICATIONS. All authorizations, approvals or permits, if
any, of any governmental authority or regulatory body of the United States or of
any state that are required in connection with the lawful issuance and sale of
the Debt pursuant to this Agreement shall be obtained and effective as of the
Closing.

              4.6 PROCEEDINGS AND DOCUMENTS. All corporate and other proceedings
in connection with the transactions contemplated at the Closing and all
documents incident thereto shall be reasonably satisfactory in from and
substance to Purchasers' special counsel, and they shall have received all such
counterpart and certified or other copies of such documents as they may
reasonably request.

              5. CONDITIONS OF THE COMPANY'S OBLIGATIONS AT CLOSING. The
obligations of the Company to each Purchaser under this Agreement are subject to
the fulfillment, on or before the Closing, of each of the following conditions,
unless otherwise waived:

              5.1 REPRESENTATIONS AND WARRANTIES. The representations and
warranties of each Purchaser contained in Section 3 shall be true and correct in
all material respects on and as


<PAGE>

of the Closing with the same effect as though such representations and
warranties had been made on and as of the Closing.

              5.2 PERFORMANCE. All covenants, agreements and conditions
contained in this Agreement to be performed by the Purchasers on or prior to the
Closing shall have been performed or complied with in all material respects.

              5.3 INVESTOR RIGHTS AGREEMENT. The Purchaser shall have duly
executed and delivered the Investor Rights Agreement to the Company.

              5.4 QUALIFICATIONS. All authorizations, approvals or permits, if
any, of any governmental authority or regulatory body of the United States or of
any state that are required in connection with the lawful issuance and sale of
the Debt pursuant to this Agreement shall be obtained and effective as of the
Closing.

       6. MISCELLANEOUS.

              6.1 SURVIVAL OF WARRANTIES. Unless otherwise set forth in this
Agreement, the warranties, representations and covenants of the Company and the
Purchasers contained in or made pursuant to this Agreement shall survive the
execution and delivery of this Agreement and the Closing for a period of one (1)
year following the Closing.

              6.2 TRANSFER; SUCCESSORS AND ASSIGNS. The terms and conditions of
this Agreement shall inure to the benefit of and be binding upon the respective
successors and assigns of the parties. Nothing in this Agreement, express or
implied, is intended to confer upon any party other than the parties hereto or
their respective successors and assigns any rights, remedies, obligations, or
liabilities under or by reason of this Agreement, except as expressly provided
in this Agreement.

              6.3 GOVERNING LAW. This Agreement and all acts and transactions
pursuant hereto and the rights and obligations of the parties hereto shall be
governed, construed and interpreted in accordance with the laws of the State of
California, without giving effect to principles of conflicts of law.

              6.4 COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original and all of which
together shall constitute one instrument.

              6.5 TITLES AND SUBTITLES. The titles and subtitles used in this
Agreement are used for convenience only and are not to be considered in
construing or interpreting this Agreement.


<PAGE>

              6.6 NOTICES. Any notice required or permitted by this Agreement
shall be in writing and shall be deemed sufficient upon delivery, when delivered
personally or by reputable overnight courier or sent by telecopier (followed
promptly with a copy by overnight courier), or forty-eight (48) hours after
being deposited in the U.S. mail, as certified or registered mail, with postage
prepaid, addressed to the party to be notified at such party's address as set
forth on the signature page or EXHIBIT A hereto, or as subsequently modified by
written notice, and if to the Company with a copy to Joel Weinstein, Rutter,
Hobbs & Davidoff Incorporated, 1900 Avenue of the Stars, Suite 2700, Los
Angeles, CA 90017, fax number (310) 286-1728.

              6.7 INVESTMENT BANKING PLACEMENT FEE. The Company represents that
it will be obligated to pay its advisor, Cappello Capital Corp. ("CAPPELLO
CAPITAL"), an investment banking placement fee, in cash, or, at Cappello
Capital's option, a Debt Investment in principal amount (or a combination
thereof), that is equal to seven and one half percent (7.5% ) of the total
amount raised by the Company, together with an option to purchase ten percent
(10%) of the principal amount of Debt placed by the Company at each Closing, at
a price equal to the face amount of such Debt so placed, which option will
expire ten (10) years from the applicable Closing. Each Purchaser agrees to
indemnify and to hold harmless the Company from any liability for any commission
or compensation in the nature of a placement or finder's fee (and the costs and
expenses of defending against such liability or asserted liability) for which
each Purchaser or any of its officers, employees, or representatives is
responsible. The Company agrees to indemnify and hold harmless each Purchaser
from any liability for any commission or compensation in the nature of a
placement or finder's fee (and the costs and expenses of defending against such
liability or asserted liability) for which the Company or any of its officers,
employees or representatives is responsible.

              6.8 FEES AND EXPENSES. The Company shall pay the reasonable fees
and expenses of counsel for Cappello Capital incurred with respect to this
Agreement, the documents referred to here in, and the transactions contemplated
hereby and thereby, provided such fees and expenses do not exceed $10,000.

              6.9 ATTORNEY'S FEES. If any action at law or in equity (including
arbitration) is necessary to enforce or interpret the terms of any of this
Agreement, the prevailing party shall be entitled to reasonable attorney's fees,
costs and necessary disbursements in addition to any other relief to which such
party may be entitled.

              6.10 AMENDMENTS AND WAIVERS. Any term of this Agreement may be
amended or waived only with the written consent of the Company and the holders
of at least a majority of the aggregate outstanding principal amount of the
Debt. Any amendment or waiver effected in accordance with this Section 6.9 shall
be binding upon the Purchasers and each transferee of the Debt, each future
holder of the underlying securities, and the Company.

              6.11 SEVERABILITY. If one or more provisions of this Agreement are
held to be unenforceable under applicable law, the parties agree to renegotiate
such provision in good faith.


<PAGE>

In the event that the parties cannot reach a mutually agreeable and enforceable
replacement for such provision, then (a) such provision shall be excluded from
this Agreement, (b) the balance of the Agreement shall be interpreted as if such
provision were so excluded and (c) the balance of the Agreement shall be
enforceable in accordance with its terms.

              6.12 DELAYS OR OMISSIONS. No delay or omission to exercise any
right, power or remedy accruing to any party under this Agreement, upon any
breach or default of any other party under this Agreement, shall impair any such
right, power or remedy of such non-breaching or non-defaulting party nor shall
it be construed to be a waiver of any such breach or default, or an acquiescence
therein, or of or in any similar breach or default thereafter occurring; nor
shall any waiver of any single breach or default be deemed a waiver of any other
breach or default theretofore or thereafter occurring. Any waiver, permit,
consent or approval of any kind or character on the part of any party of any
breach or default under this Agreement, or any waiver on the part of any party
of any provisions or conditions of this Agreement, must be in writing and shall
be effective only to the extent specifically set forth in such writing. All
remedies, either under this Agreement or by law or otherwise afforded to any
party, shall be cumulative and not alternative.

              6.13 ENTIRE AGREEMENT. This Agreement, and the documents referred
to herein constitute the entire agreement between the parties hereto pertaining
to the subject matter hereof, and any and all other written or oral agreements
relating to the subject matter hereof existing between the parties hereto are
expressly canceled.

              6.14 CONFIDENTIALITY. Each party hereto agrees that, except with
the prior written permission of the other party , it shall at all times keep
confidential and not divulge, furnish or make accessible to anyone any
confidential information, knowledge or data concerning or relating to the
business or financial affairs of the other parties to which such party has been
or shall become privy by reason of this Agreement, discussions or negotiations
relating to this Agreement, the performance of its obligations hereunder or the
ownership of Stock purchased hereunder. The provisions of this Section 6.13
shall be in addition to, and not in substitution for, the provisions of any
separate nondisclosure agreement executed by the parties hereto with respect to
the transactions contemplated hereby.

              6.15 EXCULPATION AMONG PURCHASERS. Except as set forth in Section
3.4 above, each Purchaser acknowledges that it is not relying upon any person,
firm or corporation, other than the Company and its officers and directors, in
making its investment or decision to invest in the Company. Each Purchaser
agrees that no Purchaser nor the respective controlling persons, officers,
directors, partners, agents, or employees of any Purchaser shall be liable to
any other Purchaser for any action heretofore or hereafter taken or omitted to
be taken by any of them in connection with the purchase of the Debt.


<PAGE>

              6.16 RESERVATION SHARES. The Company agrees that it shall reserve
sufficient duly authorized shares of Stock for issuance upon conversion of the
Convertible Debt Instruments and that upon such issuance, such shares shall be
validly issued, fully paid and nonassessable.



                            [Signature Pages Follow]


<PAGE>

         The parties have executed this Convertible Subordinated Debt Purchase
Agreement as of the date first written above.

                                            ADVANCED BIOTHERAPY COMPANY, INC.:



                                            By:
                                               ---------------------------------
                                               Name:
                                                    ----------------------------
                                               Title:
                                                      --------------------------
                                            Address:
                                                      --------------------------

                                                      --------------------------
                                            Facsimile:
                                                       -------------------------



                                            PURCHASER:



                                            By:
                                               ---------------------------------
                                               Name:
                                                    ----------------------------
                                                             (Print)
                                               Title:
                                                      --------------------------
                                            Address:
                                                      --------------------------

                                                      --------------------------
                                            Facsimile:
                                                       -------------------------

<PAGE>

                                    EXHIBITS
                                    --------

Exhibit A    -    Schedule of Purchasers

Exhibit B    -    Form of Convertible Debt Investment

Exhibit C    -    Schedule of Exceptions to Representations and Warranties


<PAGE>

                                    EXHIBIT A

                             SCHEDULE OF PURCHASERS



                                PRINCIPAL AMOUNT OF            PURCHASE PRICE
           NAME                 DEBT INSTRUMENT             (CASH/WIRE TRANSFER)
- ----------------------------    -------------------         --------------------


<PAGE>



                                    EXHIBIT B

                       FORM OF CONVERTIBLE DEBT INSTRUMENT


<PAGE>



                                    EXHIBIT C

                            SCHEDULE OF EXCEPTIONS TO
                         REPRESENTATIONS AND WARRANTIES

       2.10 AGREEMENTS; ACTION. The Company leases approximately 500 square feet
for administrative offices located at 6355 Topanga Canyon Boulevard, Suite 510,
Woodland Hills, California 91367 from Buccellato & Finkelstein, Inc., which
company is owned in part by Edmond Buccellato, a director and officer of the
Company. The annual base rental through December 31, 1999 was $-0-. The
remaining term of the lease is three years, ending December 31, 2002. The annual
base rental for each of the remaining lease years is $4,800. The Company also
subleases approximately 3,500 square feet of research and development space
located at 9110 Red Branch Road, Columbia, Maryland 21045 from New Horizons
Diagnostics, Inc., which company is owned by Lawrence Loomis, a director of the
Company. The annual base rental is $-0- and the term of the lease is
month-to-month.

       The Company has granted options and warrants to certain of its officers
and directors, the details of which are set forth in the Company's preliminary
Proxy Statement for the Company's stockholders meeting, scheduled for August 24,
2000, which Proxy Statement has been filed with the Securities and Exchange
Commission, a copy of which has been made available to Investors.

       The Company is indebted to Simon Skurkovich, the Company's Chairman of
the Board in the amount of $127,631.

       2.12 NO CONFLICT OF INTEREST. SEE paragraph 2.10 above. The Company is
indebted to Alexander L. Cappello, a director, and two (2) of his business
associates in the aggregate amount of $75,000, pursuant to the placement of
convertible demand notes to such individuals.

       The following directors and officers are indebted to the Company in the
amounts set forth opposite his or her name, respectively, in connection with the
grant of shares of Common Stock pursuant to the Company's stock bonus plan:

                  Boris Skurkovich:           $75,000
                  Lawrence Loomis:            $50,000
                  Edward Buccellato:          $75,000
                  Jeanne Kelley:              $36,619

       2.13 RIGHTS OF REGISTRATION AND VOTING RIGHTS. In connection with the
grant of warrants to Cappello Capital Corp. and its designees, the Company
granted full, unconditional piggyback registration rights without any holdback
obligations. With respect to the grant of shares of Stock through the Company's
Stock Bonus Plan to each of Simon V. Skurkovich, Edmond Buccellato, Boris V.
Skurkovich, Lawrence Loomis, and Jeanne Kelly, the Company granted full,
unconditional piggyback registration rights to such individuals.


<PAGE>

       2.21 CORPORATE DOCUMENTS. The Company has been unable to locate its
record book, including minutes and unanimous consents of shareholders and
directors, for the period prior to 1995.
