Exhibit 99.23

LOCK-UP AGREEMENT

February 7, 2024

Re: Securities Purchase Agreement, dated as of February 6, 2024 (the “Purchase Agreement”), between Vaccinex, Inc. (the “Company”) and the purchasers signatory thereto Ladies and Gentlemen:

Defined terms not otherwise defined in this letter agreement (the “Letter Agreement”) shall have the meanings set forth in the Purchase Agreement. The undersigned irrevocably agrees with the Company that, from the date hereof until 45 days from the Closing Date (such period, the “Restriction Period”) the undersigned will not offer, sell, contract to sell, hypothecate, pledge or otherwise dispose of (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition due to cash settlement or otherwise) by the undersigned or any Affiliate of the undersigned or any person in privity with the undersigned or any Affiliate of the undersigned), directly or indirectly, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), with respect to, any shares of Common Stock of the Company or securities convertible, exchangeable or exercisable into shares of Common Stock of the Company beneficially owned, held or hereafter acquired by the undersigned (the “Securities”), or make any demand for or exercise any right or cause to be filed a registration statement, including any amendments thereto, with respect to the registration of any shares of Common Stock or Common Stock Equivalents or publicly disclose the intention to do any of the foregoing. Beneficial ownership shall be determined and calculated in accordance with Section 13(d) of the Exchange Act.

Notwithstanding the foregoing, and subject to the conditions below, the undersigned may transfer the Securities provided that (1) in the case of any transfer pursuant to clauses i) through vii) below the Company receives a signed lock-up letter agreement (in the form of this Letter Agreement) for the balance of the Restriction Period from each donee, trustee, distributee, or transferee, as the case may be, prior to such transfer, (2) in the case of any transfer pursuant to clauses i) through vii), any such transfer shall not involve a disposition for value, (3) in the case of any transfer pursuant to clauses ii), iii), v), and vi) below, such transfer is not required to be reported during the Restriction Period with the Securities and Exchange Commission in accordance with the Exchange Act and no report of such transfer shall be made voluntarily during the Restriction Period reporting a reduction in beneficial ownership in connection with such transfer, (4) in the case of any transfer pursuant to clauses i), iv), and vii) through ix), neither the undersigned nor any donee, trustee, distributee or transferee, as the case may be, otherwise voluntarily effects any public filing or report during the Restriction Period regarding such transfer, and (5), if the undersigned is required to effect any public filing or report during the Restriction Period in the case of any transfer pursuant to clauses i), iv), and vii) through ix), with respect to transfer:

i) as a bona fide gift or gifts;

ii) to (a) any immediate family member or (b) any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned (for purposes of this Letter Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin);

iii) to any corporation, partnership, limited liability company, or other business entity all of the beneficial ownership interests of which are held by the undersigned and/or the immediate family of the undersigned;

iv) if the undersigned is a corporation, partnership, limited liability company, trust or other business entity, (a) to another corporation, partnership, limited liability company, trust or other business entity that is an affiliate (as defined in Rule 405 promulgated under the Securities Act), or to any investment fund or other entity controlling, controlled by, managing or managed by or under common control with the undersigned or (b) in the form of a distribution to partners, members, stockholders, or other equity holders of the undersigned;

v) if the undersigned is a trust, to the beneficiary of such trust;

vi) by will, other testamentary document or intestate succession to the legal representative, heir, beneficiary or a member of the immediate family of the undersigned;

vii) by operation of law, such as pursuant to a qualified domestic order, divorce settlement, divorce decree or separation agreement, or related court order related to the distribution of assets in connection with the dissolution of a marriage or civil union;

viii) pursuant to a bona fide third-party tender offer, merger, consolidation or other similar transaction that is approved by the Board of Directors of the Company and made to all holders of the Company’s capital stock the result of which is that any “person” (as defined in Section 13(d)(3) of the Exchange Act), or group of persons, becomes the beneficial owner (as defined in Rules 13d-3 and 13d-5 of the Exchange Act) of more than 50% of total voting power of the voting stock of the Company or the surviving entity (including, without limitation, the entering into any lock-up, voting or similar agreement pursuant to which the undersigned may agree to transfer, sell, tender or otherwise dispose of Securities in connection with such transaction, or vote any shares of Common Stock or other such securities in favor of any such transaction), provided that in the event that such transaction is not completed, the undersigned’s Securities shall remain subject to the provisions of this letter agreement; or

ix) to the Company in a transaction exempt from Section 16(b) of the Exchange Act upon a vesting event of the Securities or upon the exercise of options or warrants to purchase Common Stock on a “cashless” or “net exercise” basis or to cover tax withholding obligations of the undersigned in connection with such vesting or exercise (but for the avoidance of doubt, excluding all manners of exercise that would involve a sale in the open market of any securities relating to such options or warrants, whether to cover the applicable aggregate exercise price, withholding tax obligations or otherwise); provided that any Securities issued upon such exercise shall be subject to the restrictions set forth in this Letter Agreement.

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In addition, notwithstanding the foregoing, this Letter Agreement shall not restrict the delivery of shares of Common Stock to the undersigned upon (i) exercise any options granted under any employee benefit plan of the Company; provided that any shares of Common Stock or Securities acquired in connection with any such exercise will be subject to the restrictions set forth in this Letter Agreement, or (ii) the exercise of warrants; provided that such shares of Common Stock delivered to the undersigned in connection with such exercise are subject to the restrictions set forth in this Letter Agreement.

Furthermore, the undersigned may enter into any new plan established in compliance with Rule 10b5-1 of the Exchange Act; provided that (i) such plan may only be established if no public announcement or filing with the Securities and Exchange Commission, or other applicable regulatory authority, is made during the Restriction Period in connection with the establishment of such plan, other than in a quarterly report on Form 10-Q as required by the form and in which disclosure is made that no sale of shares of Common Stock may be made pursuant to such plan during the Restriction Period and (ii) no sale of shares of Common Stock is made pursuant to such plan during the Restriction Period.

The undersigned acknowledges that the execution, delivery and performance of this Letter Agreement is a material inducement to the Purchasers and the Company to complete the transactions contemplated by the Purchase Agreement and the Company shall be entitled to specific performance of the undersigned’s obligations hereunder. In furtherance of the foregoing, the undersigned acknowledges and agrees that the Company and any duly appointed transfer agent for the registration or transfer of the securities described herein may decline to make any transfer of securities if such transfer would constitute a violation or breach of this Letter Agreement. The undersigned hereby represents that the undersigned has the power and authority to execute, deliver and perform this Letter Agreement, that the undersigned has received adequate consideration therefor and that the undersigned will indirectly benefit from the closing of the transactions contemplated by the Purchase Agreement.

This Letter Agreement may not be amended or otherwise modified in any respect without the written consent of the Company and the undersigned. This Letter Agreement shall be construed and enforced in accordance with the laws of the State of New York without regard to the principles of conflict of laws. The undersigned hereby irrevocably submits to the exclusive jurisdiction of the United States District Court sitting in the Southern District of New York and the courts of the State of New York located in Manhattan, for the purposes of any suit, action or proceeding arising out of or relating to this Letter Agreement, and hereby waives, and agrees not to assert in any such suit, action or proceeding, any claim that (i) it is not personally subject to the jurisdiction of such court, (ii) the suit, action or proceeding is brought in an inconvenient forum, or (iii) the venue of the suit, action or proceeding is improper. The undersigned hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by receiving a copy thereof sent to the Company at the address in effect for notices to it under the Purchase Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. The undersigned hereby waives any right to a trial by jury. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law.

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The undersigned understands that if the Purchase Agreement (other than the provisions thereof that survive termination) terminates prior to the Closing, then this Letter Agreement shall be void and of no further force or effect.

This Letter Agreement shall be binding on successors, assigns, heirs, and personal representatives of the undersigned with respect to the Securities and any such successor, assign, heir, or personal representative shall enter into a similar agreement for the benefit of the Company. This Letter Agreement is intended for the benefit of the parties hereto and their respective successors and permitted assigns and is not for the benefit of, nor may any provisions hereof be enforced by, any of other Person.

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This Letter Agreement may be executed in two or more counterparts, all of which when taken together may be considered one and the same agreement.

Signature

Print Name

Position in Company, if any

Address for Notice:

By signing below, the Company agrees to enforce the restrictions on transfer set forth in this Letter Agreement.

By:
Name:
Title:

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