Statement of Changes in Beneficial Ownership (4)

FORM 4 ☒ Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * Webster Stephen W	2. Issuer Name and Ticker or Trading Symbol TCR2 THERAPEUTICS INC. [ TCRR ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director                    _____ 10% Owner _____ Officer (give title below)    _____ Other (specify below)
(Last)          (First)          (Middle) TCR2 THERAPEUTICS INC., 100 BINNEY STREET	3. Date of Earliest Transaction (MM/DD/YYYY) 6/1/2023
(Street) CAMBRIDGE, MA 02142	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person
(City)        (State)        (Zip)	Rule 10b5-1(c) Transaction Indication ☐ Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$0.97	6/1/2023		D (1)(2)			16800	(2)	(2)	Common Stock	16800	$0.00	0	D
Stock Option (Right to Buy)	$31.83	6/1/2023		D (1)(2)			12100	(2)	(2)	Common Stock	12100	$0.00	0	D
Stock Option (Right to Buy)	$5.21	6/1/2023		D (1)(2)			12100	(2)	(2)	Common Stock	12100	$0.00	0	D
Stock Option (Right to Buy)	$9.54	6/1/2023		D (1)(2)			10482	(2)	(2)	Common Stock	10482	$0.00	0	D

Explanation of Responses:
(1)	This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger, dated as of March 5, 2023, by and among TCR2 Therapeutics Inc. (the "Company"), Adaptimmune Therapeutics plc ("Parent") and CM Merger Sub, Inc., an indirect wholly-owned subsidiary of Parent ("Merger Sub"), as amended by that certain Amendment No. 1 to the Agreement and Plan of Merger, dated April 5, 2023, by and among the Company, Parent and Merger Sub (the "Merger Agreement"), pursuant to which Merger Sub merged with and into the Company (the "Merger") with the Company surviving the Merger as an indirect wholly-owned subsidiary of Parent effective as of June 1, 2023 (the "Effective Time").
(2)	At the Effective Time, each issued and outstanding share of common stock of the Company (each, a "Share") (excluding any Shares held in treasury of the Company or owned, directly or indirectly, by Parent or Merger Sub immediately prior to the Effective Time) was cancelled and converted into the right to receive 1.5117 (the "Exchange Ratio") American Depositary Shares of Parent ("Parent ADS") representing six ordinary shares of Parent ("Parent Ordinary Shares"). Immediately prior to the Effective Time, each option to acquire Shares (each, a "Company Option") that was outstanding and unexercised, whether or not vested, was assumed and substituted for an option to purchase a number of Parent Ordinary Shares or Parent ADSs equal to the product of (i) the total number of Shares subject to such Company Option immediately prior to the Effective Time multiplied by (ii) six times the Exchange Ratio, in the case of Parent Ordinary Shares, or the Exchange Ratio in the case of Parent ADSs.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Webster Stephen W TCR2 THERAPEUTICS INC. 100 BINNEY STREET CAMBRIDGE, MA 02142	X

Signatures
/s/ Margaret Siegel as Attorney-in-Fact		6/1/2023
**Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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