<SEC-DOCUMENT>0000899243-23-002912.txt : 20230127
<SEC-HEADER>0000899243-23-002912.hdr.sgml : 20230127
<ACCEPTANCE-DATETIME>20230127205139
ACCESSION NUMBER:		0000899243-23-002912
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20230118
FILED AS OF DATE:		20230127
DATE AS OF CHANGE:		20230127

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Das Arun
		CENTRAL INDEX KEY:			0001903997

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39103
		FILM NUMBER:		23564980

	MAIL ADDRESS:	
		STREET 1:		C/O CABALETTA BIO, INC.
		STREET 2:		2929 ARCH STREET, SUITE 600
		CITY:			PHILADELPHIA
		STATE:			PA
		ZIP:			19104

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Cabaletta Bio, Inc.
		CENTRAL INDEX KEY:			0001759138
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2929 ARCH STREET
		STREET 2:		SUITE 600
		CITY:			PHILADELPHIA
		STATE:			PA
		ZIP:			19104
		BUSINESS PHONE:		(267) 759-3100

	MAIL ADDRESS:	
		STREET 1:		2929 ARCH STREET
		STREET 2:		SUITE 600
		CITY:			PHILADELPHIA
		STATE:			PA
		ZIP:			19104
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-01-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001759138</issuerCik>
        <issuerName>Cabaletta Bio, Inc.</issuerName>
        <issuerTradingSymbol>CABA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001903997</rptOwnerCik>
            <rptOwnerName>Das Arun</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CABALETTA BIO, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2929 ARCH STREET, SUITE 600</rptOwnerStreet2>
            <rptOwnerCity>PHILADELPHIA</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Business Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.09</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-01-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>150000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2033-01-17</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>150000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>150000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">25% of the shares underlying this option shall vest and become exercisable on January 18, 2024, with the remainder vesting in twelve substantially equal quarterly installments thereafter, subject to the reporting person's continued service on each such vesting date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: /s/ Michael Gerard, as Attorney-in-Fact</signatureName>
        <signatureDate>2023-01-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
