DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Applicants’ reply to the November 3, 2025 Office Action, filed January 30, 2026, is acknowledged. Applicants cancel claim 4 and amend claims 1-2 and 5. Claims 1-3 and 5-8 are pending in this application and are under examination.
Any rejection of record in the previous office actions not addressed herein is withdrawn. New grounds of rejection are presented herein that were not necessitated by applicant’s amendment of the claims since the office action mailed November 3, 2025. Therefore, this action is not final.
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-2 and 5 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Howarth et al. (U.S. Patent No. 12,275,762, issued April 15, 2025, filed June 4, 2021, and claiming priority to PCT Patent Application No. PCT/EP2019/083905, filed December 5, 2019 and British Patent Application No. 1819850.7, filed December 5, 2018).
Regarding claim 1, Howarth discloses method of purifying proteins using a SpyCatcher/SpyTag system (column 2, line 4 to column 3, line 37). Howarth discloses that the SpyCatcher and SpyTag can use a binding partner and peptide tag to form a SpyCatcher-SpyTag-protein of interest complex (column 2, line 4 to column 3, line 37). Howarth discloses that the SpyCatcher-SpyTag-protein of interest complex can be immobilized on a solid substrate (column 16, lines 5-36). Howarth discloses washing the complex, which enables higher purity isolation (column 16, lines 5-36). Howarth discloses that the linkage may be reversible (i.e., cleavable) by enzymatic, chemical, or light (column 16, lines 5-36). Howarth discloses that the complex can be washed (column 19, lines 20-41). Howarth discloses that the SpyTag can be cleaved from the complex, followed by isolating the protein of interest (column 19, lines 20-61). Howarth discloses that the SpyCatcher polypeptide comprises a cysteine at amino acid 50 of SEQ ID NO: 6, which is at position 51 of SEQ ID NO: 22 (column 17, lines 41-51) (Appendix III).
Regarding claim 2, Howarth discloses that isolation of specific proteins can be performed on cell lysates (column 21, lines 1-16).
Regarding claim 5, Howarth discloses that the SpyCatcher polypeptide can have a sequence having at least 95% identity to SEQ ID NO: 7 (SEQ ID NO: 22) (Appendix IV).
Howarth discloses each and every limitation of claims 1-2 and 5, and therefore Howarth anticipates claim 1-2 and 5.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Howarth, as applied to claims 1-2 and 5 above, and further in view of Reddington et al. (29 Current Opinion in Chemical Biology 94-99 (2015)).
Howarth discloses purification of proteins using a SpyCatcher-SpyTag system that utilizes binding partners and tags, as discussed above.
Howarth fails to disclose or suggest that the binding pair and tag are streptavidin and biotin.
Regarding claim 3, Reddington discloses the use of SpyCatcher and SpyTag to provide covalent peptide interaction (abstract). Reddington discloses that the binding partner can be streptavidin and the tag can be biotin (paragraph bridging pages 96 and 97).
It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to use Reddington’s streptavidin/biotin binding partner/tag because these are well-known binding partners/tags, as disclosed by Reddington, in the protein purification method of Howarth because they enable the protein to be purified and isolated. One of ordinary skill in the art would have been motivated to use Reddington’s streptavidin/biotin as the binding partner/tag in the method of Howarth in order to purify the desired protein to a desired level of purity.
Claims 7 is rejected under 35 U.S.C. 103 as being unpatentable over Howarth, as applied to claims 1-2 and 5 above, and further in view of Ylera (U.S. Patent No. 11,453,883, issued September 27, 2022, and filed April 5, 2019).
Howarth discloses purification of proteins using a SpyCatcher-SpyTag system that utilizes binding partners and tags, as discussed above.
Howarth fails to disclose or suggest t that the SpyTag has a sequence of SEQ ID NO: 2.
Regarding claim 7, Ylera discloses a protein display selection method using a SpyTag/SpyCatcher system (abstract). Ylera discloses that the SpyTag can have a sequence of SEQ ID NO: 2 (SEQ ID NO: 27) (Appendix I, see the November 3, 2025 Office Action).
It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to use Ylera’s SpyTag SEQ ID NO: 27 in the protein purification method of Howarth because this is a known SpyTag protein sequence. As such, one of ordinary skill in the art would have been motivated to use any known SpyTag protein sequence, including Ylera’s, in the method of Howarth with a reasonable and predictable expectation of success.
Allowable Subject Matter
Claims 6 and 8 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. A sequence having 100% identity to the sequence of SEQ ID NO: 5 appears to be free of the prior art. A sequence having 100% identity to the sequence of SEQ ID NO: 7 appears to be free of the prior art.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to NANCY J LEITH whose telephone number is (313)446-4874. The examiner can normally be reached Monday - Thursday 8:00 AM - 6:30 PM.
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NANCY J. LEITH
Primary Examiner
Art Unit 1636
/NANCY J LEITH/Primary Examiner, Art Unit 1636