Ownership Submission
FORM 3
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  GLAXOSMITHKLINE PLC
2. Date of Event Requiring Statement (Month/Day/Year)
06/27/2018
3. Issuer Name and Ticker or Trading Symbol
Translate Bio, Inc. [TBIO]
(Last)
(First)
(Middle)
980 GREAT WEST ROAD
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

BRENTFORD MIDDLESEX, X0 TW8 9GS
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)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)
2. Amount of Securities Beneficially Owned
(Instr. 4)
3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)
4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)
2. Date Exercisable and Expiration Date
(Month/Day/Year)
3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)
4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Series A Preferred Stock   (1)   (1) Common Stock 1,674,016 $ (1) I See Explanation of Responses (5)
Series B Preferred Stock   (2)   (2) Common Stock 1,300,116 $ (2) I See Explanation of Responses (5)
Series C Preferred Stock   (3)   (3) Common Stock 454,550 $ (3) I See Explanation of Responses (5)
Stock Option (Right to Buy)   (4) 03/06/2028 Common Stock 37,800 $ 8.34 I See Explanation of Responses (4) (5)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
GLAXOSMITHKLINE PLC
980 GREAT WEST ROAD
BRENTFORD MIDDLESEX, X0 TW8 9GS
    X    

Signatures

/s/ Victoria Whyte, SVP & Company Secretary, GlaxoSmithKline Plc 06/27/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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).
(1) The Series A Preferred Stock is convertible into Common Stock on a 5.5555-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(2) The Series B Preferred Stock is convertible into Common Stock on a 5.5555-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(3) The Series C Preferred Stock is convertible into Common Stock on a 5.5555-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(4) This stock option was granted on March 7, 2018 with respect to 37,800 Common Shares with 25% of the shares vesting on March 7, 2019, and thereafter 2.0833% vesting monthly until March 7, 2022. The stock option was granted to Brian M. Gallagher, Jr. as director's compensation. As a Partner and Vice President at S.R. One, Limited and an employee of GlaxoSmithKline LLC, Brian M. Gallagher, Jr. is obligated to transfer any shares issued under the stock option to S.R. One, Limited, an indirect, wholly-owned subsidiary of GlaxoSmithKline plc.
(5) The shares reported herein are held of record by S.R. One, Limited, an indirect, wholly-owned subsidiary of GlaxoSmithKline plc (the "Reporting Person").

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