這證明是 CUSIP 的所有者註明日期為會籤並註冊： COMPUTERSHARE TRUST COMPANY，北卡羅來納州過户代理和註冊商，普通股面值 0.001 美元普通股的某些定義見反向證書編號股票。總裁兼首席執行官高級副總裁、首席法務官兼祕書作者：授權簽名 AXCELLA HEALTH INC. 根據特拉華州法律註冊成立 Axcella Health Inc.（以下簡稱 “公司”）的全額支付且不可評估的普通股，可在公司賬簿上親自轉讓或由經正式授權的律師轉讓，但須交出經適當認可的本證書。本證書和特此代表的股票的發行和持有須遵守經修訂的公司註冊證書和經修訂的公司章程（副本存檔在公司和過户代理處）的所有規定，每位持有人均同意所有條款。除非由過户代理人和註冊商會籤和註冊，否則證書無效。見證公司的傳真印章及其正式授權官員的傳真簽名。 2008 年 8 月 27 日特拉華州 INCOMPLATION AXCELLA HEALTH, INC. ZQ|CERT#|COY|CLS|RGSTRY|ACCT#|TRANSTYPE|RUN#|TRANS# 05454B 20 4 dd-MM-MM-YYYY **00000 ***************** *********** ************* *********** *********** *********** *********** *********** *********** *********** *********** 000000 ************ ** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·戴維先生樣本**** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大大衞先生樣本 **** 亞歷山大先生David Sample **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·戴維先生樣本**** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 亞歷山大·大衞先生樣本 **** 先生樣本 **** 樣本先生 **000000**分享****000000**分享****000000**分享****0000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**Shares**000000**res****000000**股票*** *000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票********股********股**** 000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**分享****000000**股票****0000**股票****0000**分享****000000**股票****0000**股票****0000**股票****0000**股票****0000**股票****000000**股票****0000**股票****0000**股票****0000**股票****000000**股票****000000**分享******0000**股票****000000**股票****0000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股****0000**股********000000**股票****000000**股票****000000**股票****000000**股票****0000**股票****0000 00**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****00000000**股票****000000**股票****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享****000000**分享******股票****000000**股票****000000**股票****00000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000** 股票****000000**股票****000000**股票****000000**股票****000000**股票****0000**股票****000000**Shares**000000** 股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**股票****000000**S ***零十萬零一百零*** 先生樣本和太太樣品和 MR. SAMPLE & MRS SAMPLE ZQ00000000 總交易 1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890 證書編號編號/編號 6 5 4 3 2 1 Denom。 6 5 4 3 2 1 總計 7 6 5 4 3 2 1 ADD 4 3 2 1 ADD 4 3 2 1 加 4 加 3 加 2 添加 1 名稱（如果有的話） MR A SAMPLE PO BOX 505006，肯塔基州路易斯維爾 40233-5006 CUSIP/IDENTIFIER XXXXX X 持有人編號 XXXXXXXX 保險價值 1,000,000.00 股票數量 123456 DTC 123356 45678 123456789012345 此證書可在轉讓代理指定的城市進行轉讓，可通過 www.computershare.com 在線獲得

The IRS requires that the named transfer agent (“we”) report the cost basis of certain shares or units acquired after January 1, 2011. If your shares or units are covered by the legislation, and you requested to sell or transfer the shares or units using a specific cost basis calculation method, then we have processed as you requested. If you did not specify a cost basis calculation method, then we have defaulted to the first in, first out (FIFO) method. Please consult your tax advisor if you need additional information about cost basis. If you do not keep in contact with the issuer or do not have any activity in your account for the time period specified by state law, your property may become subject to state unclaimed property laws and transferred to the appropriate state. For value received, ____________________________hereby sell, assign and transfer unto ________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________ _______________________________________________________________________________________________________________________ Shares _______________________________________________________________________________________________________________________ Attorney Dated: __________________________________________20__________________ Signature: ____________________________________________________________ Signature: ____________________________________________________________ Notice: The signature to this assignment must correspond with the name as written upon the face of the certificate, in every particular, without alteration or enlargement, or any change whatever. PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING POSTAL ZIP CODE, OF ASSIGNEE) of the common stock represented by the within Certificate, and do hereby irrevocably constitute and appoint to transfer the said stock on the books of the within-named Axcella Health Inc. with full power of substitution in the premises. . AXCELLA HEALTH INC. THE COMPANY WILL FURNISH WITHOUT CHARGE TO EACH SHAREHOLDER WHO SO REQUESTS, A SUMMARY OF THE POWERS, DESIGNATIONS, PREFERENCES AND RELATIVE, PARTICIPATING, OPTIONAL OR OTHER SPECIAL RIGHTS OF EACH CLASS OF STOCK OF THE COMPANY AND THE QUALIFICATIONS, LIMITATIONS OR RESTRICTIONS OF SUCH PREFERENCES AND RIGHTS, AND THE VARIATIONS IN RIGHTS, PREFERENCES AND LIMITATIONS DETERMINED FOR EACH SERIES, WHICH ARE FIXED BY THE ARTICLES OF INCORPORATION OF THE COMPANY, AS AMENDED, AND THE RESOLUTIONS OF THE BOARD OF DIRECTORS OF THE COMPANY, AND THE AUTHORITY OF THE BOARD OF DIRECTORS TO DETERMINE VARIATIONS FOR FUTURE SERIES. SUCH REQUEST MAY BE MADE TO THE OFFICE OF THE SECRETARY OF THE COMPANY OR TO THE TRANSFER AGENT, THE BOARD OF DIRECTORS MAY REQUIRE THE OWNER OF A LOST OR DESTROYED STOCK CERTIFICATE, OR HIS LEGAL REPRESENTATIVES. TO GIVE THE COMPANY A BOND TO INDEMNIFY IT AND ITS TRANSFER AGENTS AND REGISTRARS AGAINST ANY CLAIM THAT MAY BE MADE AGAINST THEM ON ACCOUNT OF THE ALLEGED LOSS OR DESTRUCTION OF ANY SUCH CERTIFICATE. Signature(s) Guaranteed: Medallion Guarantee Stamp THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (Banks, Stockbrokers, Savings and Loan Associations and Credit Unions) WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15. The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations: TEN COM - as tenants in common UNIF GIFT MIN ACT -............................................Custodian ................................................ (Cust) (Minor) TEN ENT - as tenants by the entireties under Uniform Gifts to Minors Act ........................................................ (State) JT TEN - as joint tenants with right of survivorship UNIF TRF MIN ACT -............................................Custodian (until age ................................) and not as tenants in common (Cust) .............................under Uniform Transfers to Minors Act ................... (Minor) (State) Additional abbreviations may also be used though not in the above list.