DETAILED CORRESPONDENCE
Status of the Application
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claims 1-3, 5-7, 9, 10, 13-15, 17-19, 21, 22, 24, 25, 34, 36, 37, and 39 are pending in the application.
Applicant’s amendment to the claims, filed April 20, 2026, is acknowledged. This listing of the claims replaces all prior versions and listings of the claims.
Applicant’s amendment to the specification, filed April 20, 2026, is acknowledged.
Applicant’s submission of a substitute sequence listing, filed April 20, 2026, is acknowledged.
Applicant’s remarks filed April 20, 2026 in response to the non-final rejection filed January 21, 2026 are acknowledged and have been fully considered.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Restriction/Election
In response to a requirement for restriction/election filed May 27, 2025, applicant elected without traverse the invention of Group II, claims 13-15, 17-19, 21, 22, and 39, drawn to the technical feature of a method for covalently modifying a red blood cell, in the reply filed July 17, 2025.
Claims 1-3, 5-7, 9, 10, 24, 25, 34, 36, and 37 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to nonelected inventions, there being no allowable generic or linking claim.
Specification/Informalities
The objection to the specification for the use of trade names or marks is withdrawn in view of applicant’s amendment to the specification.
Sequence Compliance
The objections to the specification for disclosing the size of the ASCII text file in bytes and failing to identify sequences with a sequence identifier are withdrawn in view of applicant’s amendment to the specification.
Claim Objections
The objection to claim 17 is withdrawn in view of applicant’s amendment to recite “95% sequence identity.”
Claim Rejections - 35 USC § 112(b)
The rejection of claims 13-15, 17-19, 21, 22, and 39 under 35 U.S.C. 112(b) as being indefinite for:
lacking antecedent basis in the recitation of “the glycine(n) and/or lysine ε-amino group at internal sites of the extracellular domain of at least one endogenous, non-engineered membrane protein of a red blood cell” in lines 1-3 of claim 13;
being confusing in the recitation of “the extracellular domain of at least one endogenous, non-engineered membrane protein of a red blood cell,”
failing to define “n” in the recitation of “glycine(n)” in claims 13 and 14;
reciting the trademark “UniProt” in claim 14;
lack of clarity of the scope of proteins encompassed by the recited UniProt Accession Numbers in claim 14;
reciting “the RBC is a natural RBC a natural human RBC” in claim 15;
reciting “the sortase is a Staphylococcus aureus transpeptidase A variant (mgSrtA)” in claim 17; and
reciting “on the surface of the RBC” in line 2 of claim 22
are withdrawn in view of
applicant’s amendment to claim 13 to recite “a non-N-terminal glycine(n) and lysine ε-amino group at internal sites of the extracellular domain of at least one endogenous, non-engineered membrane protein on the surface of a red blood cell” in lines 1-3,
applicant’s amendment to claim 13 to recite “the extracellular domain of at least one endogenous, non-engineered membrane protein on the surface of a red blood cell,”
applicant’s amendment to claim 13 to recite “wherein n is 1 or 2,” and applicant’s amendment to claim 14 to delete “optionally” in the phrase “optionally n being 1 or 2,”
applicant’s amendment to claim 14 to delete the trademark/trade name “UniProt,”
applicant’s amendment to claim 14 to replace abbreviations with protein names,
applicant’s amendment to claim 15 to recite “the RBC is a natural human RBC,”
applicant’s amendment to claim 17 to delete the parenthetical phrase “(mgSrtA),” and
applicant’s amendment to claim 13 to recite “on the surface of a red blood cell.”
Claim Rejections - 35 USC § 103
Claims 13-15, 17-19, 21, 22, and 39 are rejected under 35 U.S.C. 103 as being unpatentable over Swee et al. (WO 2014/183066 A2; cited on the IDS filed January 6, 2023; hereafter “Swee”) in view of Chen et al. (CN 109797194 A; cited on the IDS filed January 6, 2023; hereafter “Chen”). Reference is made to applicant’s machine translation of Chen (hereafter “Translation”). This rejection has been modified from its previous version in order to address applicant’s amendment to the claims.
As amended, the claims are drawn to a method for covalently modifying a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of the extracellular domain of at least one endogenous, non-engineered membrane protein on the surface of a red blood cell (RBC), wherein n is 1 or 2, and wherein the method comprises
contacting the RBC with a sortase substrate that comprises a sortase recognition motif and an agent, in the presence of a sortase under conditions suitable for the sortase to conjugate the sortase substrate to the glycine(n) and lysine ε-amino group at internal sites of the extracellular domain of the at least one endogenous, non-engineered membrane protein of the RBC by a sortase-mediated reaction, wherein the sortase-mediated reaction comprises a sortase-mediated glycine conjugation and/or a sortase-mediated lysine side chain ε-amino group conjugation, wherein the sortase is a Staphylococcus aureus transpeptidase A variant comprising an amino acid sequence having at least 90% sequence identity to the amino acid sequence as set forth in SEQ ID NO: 3 or 27, and comprising the mutations of P94R/S, D124G, D160N, D165A, Y187L, E189R, K190E K196T, and F200L and optionally E105K and/or E108E/Q, wherein the numbering of the mutations is according to the numbering of SEQ ID NO: 1.
Regarding instant claim 13, claim 1 of Swee recites a method of conjugating an agent to an animal cell, the method comprising: contacting an animal cell with a sortase substrate that comprises a sortase recognition sequence and an agent in the presence of a sortase under conditions suitable for the sortase to conjugate the sortase substrate to an endogenous, non-engineered polypeptide expressed by the animal cell; and
claim 2 of Swee recites the method of claim 1, wherein the sortase substrate is conjugated to an extracellular portion of an endogenous, non-engineered polypeptide expressed by the cell.
Swee teaches sortase can be used for modification of eukaryotic cell surfaces without requiring that the cells be engineered to express polypeptides comprising a sortase recognition sequence or nucleophilic acceptor sequence, noting that such polypeptides may comprise a sequence of one or more glycines exposed at the cell surface, e.g., in an N-terminal domain, available to act as a nucleophile in a reaction in which sortase is used to conjugate a sortase substrate to the polypeptide (p. 56, paragraph [0066]). Swee teaches the polypeptide modified by the sortase is an integral membrane protein or a peripheral membrane protein (p. 63, paragraph [0088]).
Swee teaches the cells include red blood cells (p. 98, paragraph [0169]) and teaches examples of sortase-mediated conjugation of red blood cells with various agents modified to comprise a sortase recognition sequence (Examples 28-32 beginning at p. 259).
Swee teaches a variant of a naturally occurring sortase may be used (p. 75, paragraph [00118]) and teaches a variant of a wild-type S. aureus sortase comprising P94R/S, D160N, D165A, K190E, and K196T mutations (p. 76, paragraph [00119]).
The differences between Swee and claim 13 are:
Swee does not teach or suggest a Staphylococcus aureus transpeptidase A variant comprising the mutations of P94S/R, D124G, D160N, D165A, Y187L, E189R, K190E K196T, and F200L and optionally E105K and/or E108E/Q; and
Swee does not explicitly teach the sortase substrate is conjugated to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of an extracellular domain of at least one endogenous, non-engineered membrane protein.
Regarding difference 1), Chen teaches S. aureus sortase mutant 1 comprising the mutations P94R/D124G/D160N/D165A/Y187L/E189R/K190E/K196T/F200L (Translation at p. 3, middle) and referred to as “mgSrtA” (Translation at p. 4, fifth full paragraph). Chen teaches mgSrtA can bind a molecule comprising a LPXTG sequence to the cell membrane surface (Translation at p. 4, first paragraph). Chen teaches the surface of the cell membrane has few oligo glycines and mgSrtA exhibits greatly improved efficiency at single glycine residues on the surface of the cell membrane (Translation at p. 5, second paragraph). Chen teaches mgSrtA mutant 1 comprises the mutations P94R/D124G/D160N/D165A/Y187L/E189R/K190E/K196T/F200L (Translation at p. 3, middle) and has the amino acid sequence of SEQ ID NO: 1 (Translation, beginning at p. 7). SEQ ID NO: 1 of Chen is identical to instant SEQ ID NO: 3 (see Appendix for sequence alignment).
In view of the combined teachings of Swee and Chen, it would have been obvious to one of ordinary skill in the art before the effective filing date to use mgSrtA of Chen as the variant sortase in the method of Swee. One would have been motivated and would have expected success because Swee taught the use of a variant sortase comprising the mutations P94R/S, D160N, D165A, K190E, and K196T to conjugate the sortase substrate to a glycine exposed at the cell surface, Chen taught mgSrtA comprising the mutations P94R/S, D160N, D165A, K190E, and K196T, and Chen taught the surface of the cell membrane has few oligo glycines and mgSrtA exhibits greatly improved efficiency at single glycine residues on the surface of the cell membrane.
Regarding difference 2), the combination of Swee and Chen does not teach or suggest the sortase substrate is conjugated to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites. However, according to the instant specification, mgSrtA conjugates a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein of RBCs (e.g., paragraph [00155] and Tables 4 and 5). Since inherency may be relied upon in a rejection under 35 U.S.C. 103 (MPEP 2112) and the inherent feature need not be recognized at the relevant time (MPEP 2112.II), it is the examiner’s position that using the mgSrtA of Chen as the variant sortase in the method of Swee would have inherently resulted in conjugating a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein of RBCs.
Regarding instant claim 14, the combination of Swee and Chen does not teach or suggest the sortase substrate is conjugated to a membrane protein recited in claim 14. However, according to the instant specification, mgSrtA conjugates a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of the membrane proteins recited in claim 14 (e.g., Tables 4 and 5) and it is the examiner’s position that using the mgSrtA of Chen as the variant sortase in the method of Swee would have inherently resulted in conjugating a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein recited in claim 14.
Regarding instant claim 15, Swee teaches the cell surfaces can be modified without requiring that the cells be engineered to express polypeptides comprising a sortase recognition sequence or nucleophilic acceptor sequence (p. 56, paragraph [0066]).
Regarding instant claims 17 and 18, Chen teaches mgSrtA mutant 1 comprises the mutations P94R/D124G/D160N/D165A/Y187L/E189R/K190E/K196T/F200L (Translation at p. 3, middle) and has the amino acid sequence of SEQ ID NO: 1 (Translation, beginning at p. 7). SEQ ID NO: 1 of Chen is identical to instant SEQ ID NO: 3 (see Appendix for sequence alignment).
Regarding instant claim 19, Swee teaches sortase substrates include a sortase recognition motif at their C-terminus and teaches the exemplary sortase recognition motifs LPXTGG and LPETGG (p. 44, paragraph [0053]).
Regarding instant claim 21, Swee teaches a wide variety of agents may be conjugated (p. 2, paragraph [0007]) and claim 20 of Swee recites the agent comprises an amino acid, a peptide, a protein, a polynucleotide, a carbohydrate, a tag, a metal atom, a chelating agent, a contrast agent, a catalyst, a polymer, a recognition element, a small molecule, a lipid, a label, an epitope, an antigen, a therapeutic agent, a cross-linker, a toxin, a radioisotope, an antibody, an antibody domain, a click chemistry handle, a virus, a cell, or a particle, and Chen teaches a labeling molecule including a small molecule or a biological macromolecule such as biotin, fluorescent dye, enhanced and green fluorescent protein (eGFP) (Translation at p. 4, first full paragraph).
Regarding instant claim 22, Swee teaches the exemplary sortase recognition motifs LPXTGG and LPETGG (p. 44, paragraph [0053]) and shows a representation of a sortase-modified cell (pp. 60-61, paragraph [0080]), which is encompassed by A1-LPXT-P1 in claim 22.
Regarding instant claim 39, Swee teaches the average circulation time or plasma half-life may be increased (pp. 65-66, paragraph [0093]).
Therefore, the invention of claims 13-15, 17-19, 21, 22, and 39 would have been obvious to one of ordinary skill in the art before the effective filing date.
RESPONSE TO REMARKS: In summary, applicant argues Swee and Chen are directed to sortase-mediated conjugation of a sortase substrate to an N-terminal glycine, while the claims recite sortase-mediated conjugation of a sortase substrate to a glycine(n) and lysine ε-amino group at internal sites of extracellular domains of endogenous RBC membrane proteins. Applicant argues the present invention is based on the inventors’ unexpected finding that conjugation to RBCs can be achieved at internal glycine(n) and lysine ε-amino groups using the recited sortase variant.
Applicant’s arguments are not found persuasive. There is no dispute that the combination of Swee and Chen do not teach or suggest conjugation of a sortase substrate to a glycine(n) and lysine ε-amino group at internal sites of extracellular domains of endogenous RBC membrane proteins. However, as noted above, inherency may be relied upon in a rejection under 35 U.S.C. 103 (MPEP 2112) and although the combination of Swee and Chen does not teach and/or suggest conjugation of a sortase substrate to a glycine(n) and lysine ε-amino group at internal sites of extracellular domains of endogenous RBC membrane proteins, the inherent feature need not be recognized at the relevant time (MPEP 2112.II). Since the instant specification acknowledges that mgSrtA conjugates a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein of RBCs, it is the examiner’s position that using the mgSrtA of Chen as the variant sortase in the method of Swee would have inherently conjugated a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein of RBCs.
While applicant alleges their results are unexpected, the applicant’s results fail to rebut a prima facie case of obviousness. First, applicant’s results are not compared with the closest prior art as required by MPEP 716.02(e), which appears to be the reference of Swee. Second, applicant’s results are based on conjugation using mgSrtA, while the claims recite variants comprising an amino acid sequence having at least 90% or 95% sequence identity to the amino acid sequence as set forth in SEQ ID NO: 3 or 27, and comprising the mutations of P94R/S, D124G, D160N, D165A, Y187L, E189R, K190E K196T, and F200L and optionally E105K and/or E108E/Q, wherein the numbering of the mutations is according to the numbering of SEQ ID NO: 1, which is not commensurate in scope with the claimed invention as required by MPEP 716.02(d). “Commensurate in scope” means that the evidence provides a reasonable basis for concluding that the untested embodiments encompassed by the claims would behave in the same manner as the tested embodiments. See In re Lindner, 457 F.2d 506, 508 (CCPA 1972). While nonobviousness of a broader claimed range can be supported by evidence based on unexpected results from testing a narrower range (MPEP 716.02(d).I), the effects of amino acid modification are highly unpredictable (see, e.g., MPEP 2144.08.II.A.4.(c)) and there is no evidence of record that the untested embodiments encompassed by the claims would behave in the same manner as the tested embodiment(s).
Claim Rejections - Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 13-15, 17-19, 21, 22, and 39 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 5, 7, 10-12, and 18 of co-pending application 18/251,030 (reference application). This provisional rejection has been modified from its previous version in order to address applicant’s amendment to the claims.
Regarding instant claims 13 and 17-19, claim 1 of the reference application recites a method for covalently modifying at least one membrane protein of a red blood cell (RBC), comprising contacting the RBC with a sortase substrate that comprises a sortase recognition motif and an agent, in the presence of a sortase under conditions suitable for the sortase to conjugate the sortase substrate to the at least one membrane protein of the RBC by a sortase-mediated reaction,
wherein the sortase substrate comprises a structure of A1-Sp-M, in which
A1 represents the agent, Sp represents one or more optional spacers, and M represents the sortase recognition motif comprising an unnatural amino acid located at position 5 from the direction of N-terminal to C-terminal of the sortase recognition motif, wherein the unnatural amino acid is an optionally substituted hydroxyl carboxylic acid having a formulae of CH2OH-(CH2)n-COOH, n being an integer from 0 to 3, preferably n=0;
claim 5 of the reference application recites the method of claim 1, the wherein the at least one membrane protein is at least one endogenous, non-engineered membrane protein and the sortase substrate is conjugated to the at least one endogenous, non-engineered membrane protein of the RBC by a sortase-mediated glycine conjugation and/or a sortase-mediated lysine side chain ε-amino group conjugation, wherein the sortase-mediated glycine conjugation and/or the sortase-mediated lysine side chain ε-amino group conjugation occur at least on glycine(n) and/or lysine ε-amino group at internal sites of the extracellular domain of the at least one endogenous, non-engineered membrane protein, optionally n being 1 or 2; and
claim 10 of the reference application recites the method of claim 9, wherein the sortase is a mgSrtA, and wherein the mgSrtA comprises an amino acid sequence having the amino acid sequence as set forth in SEQ ID NO: 3 (SEQ ID NO: 3 of the reference application is identical to instant SEQ ID NO: 3 and comprises the mutations P94R/S, D124G, D160N, D165A, Y187L, E189R, K190E K196T, and F200L relative to instant SEQ ID NO: 1).
Regarding instant claim 14, the claims of the reference application do not recite a membrane protein recited in claim 14. However, according to the instant specification, mgSrtA conjugates a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of the membrane proteins recited in claim 14 (e.g., Tables 4 and 5) and it is the examiner’s position that practicing the method of the claims of the reference application would inherently result in conjugating a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein recited in claim 14.
Regarding instant claim 15, claim 7 of the reference application recites the method of claim 5, wherein the RBC has not been genetically engineered to express a protein comprising a sortase recognition motif or a nucleophilic acceptor sequence, and preferably the RBC is a natural RBC such as a natural human RBC.
Regarding instant claim 21, claim 11 of the reference application recites the method of claim 1, wherein the agent comprises a binding agent, a therapeutic agent, or a detection agent.
Regarding instant claim 22, claim 12 of the reference application recites the method of claim 1, wherein the covalently modified at least one membrane protein on the surface of the BRC comprises a structure of A1-L1-P1, in which L1 is linked to a glycine(n) in P1, and/or a structure of A1-L1-P2 in which L1 is linked to the side chain ε-amino group of lysine in P2, wherein n is 1 or 2; A1 represents the agent; L1 is selected from the group consisting of LPXT, LPXA, LPXS, LPXL, LPXV, LGXT, LAXT, LSXT, NPXT, MPXT, IPXT, SPXT, VPXT, and YPXR; P1 and P2 independently represent the at least one membrane protein; and X represents any amino acid.
Regarding instant claim 39, claim 18 of the reference application recites the method of claim 1, wherein the method is for increasing the circulation time or plasma half-life of the agent in a subject, comprising providing the sortase substrate that comprises the sortase recognition motif and the agent, and conjugating the sortase substrate in the presence of a sortase under conditions suitable for the sortase to conjugate the sortase substrate to at least one membrane protein of the red blood cell by a sortase-mediated reaction.
Therefore, claims 13-15, 17-19, 21, 22, and 39 of this application are unpatentable over claims 1, 5, 7, 10-12, and 18 of the reference application. This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 13-15, 17-19, 21, 22, and 39 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claim 18 of co-pending application 18/264,098 (reference application) in view of Swee and Chen. This provisional rejection has been modified from its previous version in order to address applicant’s amendment to the claims.
Regarding instant claim 13, claim 18 of the reference application recites a method for preparing the red blood cell of claim 1, comprising contacting a red blood cell (RBC) with a sortase substrate that comprises a sortase recognition motif and an agent, in the presence of a sortase under conditions suitable for the sortase to conjugate the sortase substrate to the at least one endogenous, non-engineered membrane protein of the RBC by a sortase-mediated reaction, optionally by a sortase-mediated glycine conjugation and/or a sortase-mediated lysine side chain ε-amino group conjugation, wherein the agent comprises a uric acid degrading polypeptide,
wherein the sortase substrate comprises a structure of (A1-Sp)m-M, in which A1 represents an agent, Sp represents the optional spacer, and M represents a sortase recognition motif; m being an integer greater than or equal to 1, optionally m=1 to 3, wherein M is LPET*G with * being 2-hydroxyacetic acid.
The differences between claim 18 of the reference application and claim 13 of this application are:
claim 18 does not recite the sortase is a Staphylococcus aureus transpeptidase A variant comprising the mutations of P94R/S, D124G, D160N, D165A, Y187L, E189R, K190E K196T, and F200L and optionally E105K and/or E108E/Q, wherein the numbering of the mutations is according to the numbering of SEQ ID NO: 1; and
claim 18 does not recite the sortase substrate is conjugated to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of an extracellular domain of at least one endogenous, non-engineered surface membrane protein.
Regarding difference 1), Chen teaches S. aureus sortase mutant 1 comprising the mutations P94R/D124G/D160N/D165A/Y187L/E189R/K190E/K196T/F200L (Translation at p. 3, middle) and referred to as “mgSrtA” (Translation at p. 4, fifth full paragraph). Chen teaches mgSrtA can bind a molecule comprising a LPXTG sequence to the cell membrane surface (Translation at p. 4, first paragraph). Chen teaches the surface of the cell membrane has few oligo glycines and mgSrtA exhibits greatly improved efficiency at single glycine residues on the surface of the cell membrane (Translation at p. 5, second paragraph).
In view of the teachings of Chen, it would have been obvious to one of ordinary skill in the art to use mgSrtA of Chen as the sortase in the method of claim 18 of the reference application. One would have been motivated and would have expected success to use mgSrtA of Chen as the sortase in the method of claim 18 of the reference application because the method of claim 18 of the reference application includes a sortase-mediated glycine conjugation, and Chen taught mgSrtA comprising the mutations P94R/D124G/D160N/D165A/Y187L/E189R/K190E/K196T/F200L with greatly improved efficiency at single glycine residues on the surface of the cell membrane.
Regarding difference 2), Swee teaches sortase can be used for modification of eukaryotic cell surfaces without requiring that the cells be engineered to express polypeptides comprising a sortase recognition sequence or nucleophilic acceptor sequence, noting that such polypeptides may comprise a sequence of one or more glycines exposed at the cell surface, available to act as a nucleophile in a reaction in which sortase is used to conjugate a sortase substrate to the polypeptide (p. 56, paragraph [0066]).
In view of the teachings of Swee, it would have been obvious to one of ordinary skill in the art for the at least one endogenous, non-engineered membrane protein of the RBC to comprise a sequence of one or more glycines exposed at the cell surface. One would have been motivated and would have expected the at least one endogenous, non-engineered membrane protein of the RBC to comprise a sequence of one or more glycines exposed at the cell surface because Swee taught polypeptides modified by sortase may comprise a sequence of one or more glycines exposed at the cell surface.
While Swee does not teach the sortase substrate is conjugated to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of an extracellular domain of at least one endogenous, non-engineered surface membrane protein, according to the instant specification, mgSrtA conjugates a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of the membrane proteins recited in claim 14 (e.g., Tables 4 and 5) and it is the examiner’s position that using the mgSrtA of Chen as the sortase in the method of claim 18 of the reference application would inherently result in conjugating a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein recited in claim 14.
Regarding instant claim 14, the claims of the reference application do not recite a membrane protein recited in claim 14. However, according to the instant specification, mgSrtA conjugates a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of the membrane proteins recited in claim 14 (e.g., Tables 4 and 5) and it is the examiner’s position that using the mgSrtA of Chen as the sortase in the method of claim 18 of the reference application would inherently result in conjugating a sortase substrate to a non-N-terminal glycine(n) and a lysine ε-amino group at internal sites of a membrane protein recited in claim 14.
Regarding instant claim 15, Swee teaches the cell surfaces can be modified without requiring that the cells be engineered to express polypeptides comprising a sortase recognition sequence or nucleophilic acceptor sequence (p. 56, paragraph [0066]).
Regarding instant claims 17 and 18, Chen teaches mgSrtA mutant 1 comprises the mutations P94R/D124G/D160N/D165A/Y187L/E189R/K190E/K196T/F200L (Translation at p. 3, middle) and has the amino acid sequence of SEQ ID NO: 1 (Translation, beginning at p. 7). SEQ ID NO: 1 of Chen is identical to instant SEQ ID NO: 3 (see Appendix for sequence alignment).
Regarding instant claim 19, Swee teaches sortase substrates include a sortase recognition motif at their C-terminus and teaches the exemplary sortase recognition motifs LPXTGG and LPETGG (p. 44, paragraph [0053]).
Regarding instant claim 21, claim 18 of the reference application recites the agent comprises a uric acid degrading polypeptide. Also, Swee teaches a wide variety of agents may be conjugated (p. 2, paragraph [0007]) and claim 20 of Swee recites the agent comprises an amino acid, a peptide, a protein, a polynucleotide, a carbohydrate, a tag, a metal atom, a chelating agent, a contrast agent, a catalyst, a polymer, a recognition element, a small molecule, a lipid, a label, an epitope, an antigen, a therapeutic agent, a cross-linker, a toxin, a radioisotope, an antibody, an antibody domain, a click chemistry handle, a virus, a cell, or a particle, and Chen teaches a labeling molecule including a small molecule or a biological macromolecule such as biotin, fluorescent dye, enhanced and green fluorescent protein (eGFP) (Translation at p. 4, first full paragraph).
Regarding instant claim 22, Swee teaches the exemplary sortase recognition motifs LPXTGG and LPETGG (p. 44, paragraph [0053]) and shows a representation of a sortase-modified cell (pp. 60-61, paragraph [0080]), which is encompassed by claim 22.
Regarding instant claim 39, Swee teaches the average circulation time or plasma half-life may be increased (pp. 65-66, paragraph [0093]).
Therefore, claims 13-15, 17-19, 21, 22, and 39 of this application are unpatentable over claim 18 of the reference application in view of Swee and Chen. This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
RESPONSE TO REMARKS: In summary, applicant argues the instant application has an earlier patent term filing date than those of the reference applications and the provisional rejections should be withdrawn in accordance with MPEP 1490(VI)(D)(2)(a).
Applicant’s arguments are not found persuasive because the provisional rejections are not the only remaining rejections in this application.
Conclusion
Status of the claims:
Claims 1-3, 5-7, 9, 10, 13-15, 17-19, 21, 22, 24, 25, 34, 36, 37, and 39 are pending.
Claims 1-3, 5-7, 9, 10, 24, 25, 34, 36, and 37 are withdrawn from consideration.
Claims 13-15, 17-19, 21, 22, and 39 are rejected.
No claim is in condition for allowance.
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DAVID J STEADMAN whose telephone number is (571)272-0942. The examiner can normally be reached Monday to Friday, 7:30 AM to 4:00 PM.
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/David Steadman/Primary Examiner, Art Unit 1656
APPENDIX
BGJ38537
ID BGJ38537 standard; protein; 181 AA.
XX
AC BGJ38537;
XX
DT 22-AUG-2019 (first entry)
XX
DE Staphylococcus aureus SrtA mutant, SEQ ID 1.
XX
KW Sorting enzyme A; SrtA protein; mutein; protein labeling.
XX
OS Staphylococcus aureus.
OS Synthetic.
XX
CC PN CN109797194-A.
XX
CC PD 24-MAY-2019.
XX
CC PF 24-JAN-2019; 2019CN-10067616.
XX
PR 24-JAN-2019; 2019CN-10067616.
XX
CC PA (UYPK ) UNIV PEKING.
XX
CC PI Chen P, Chen L, Ge Y, Liu S;
XX
DR WPI; 2019-47417N/60.
DR N-PSDB; BGJ38543.
XX
CC PT Labeling cell membrane surface comprises carrying LPXTG sequence is
CC PT linked to a cell membrane surface using Staphylococcus aureus sortase A
CC PT mutant.
XX
CC PS Claim 3; SEQ ID NO 1; 18pp; Chinese.
XX
CC The present invention relates to a novel method for labeling a cell
CC membrane surface. The method comprises: ligating a marker comprising a
CC LPXTG peptide to the cell membrane surface using a Staphylococcus aureus
CC sorting enzyme A (SrtA) (BA000018) mutant selected from SEQ ID NO: 1-6
CC (see BGJ38537-BGJ38542). The invention further claims a method for
CC detecting cell-cell interaction displaying the Staphylococcus aureus SrtA
CC mutant. The method of the present invention is useful for labeling a cell
CC membrane surface and for detecting cell-cell interaction. The present
CC sequence represents a Staphylococcus aureus SrtA mutant
CC (P94R/D124G/D160N/D165A/Y187L/E189R/K190E/K196T/F200L) which is
CC specifically claimed and can be used in the method of the present
CC invention for labeling a cell membrane surface.
XX
SQ Sequence 181 AA;
Query Match 100.0%; Score 944; Length 181;
Best Local Similarity 100.0%;
Matches 181; Conservative 0; Mismatches 0; Indels 0; Gaps 0;
Qy 1 KPHIDNYLHDKDKDEKIEQYDKNVKEQASKDKKQQAKPQIPKDKSKVAGYIEIPDADIKE 60
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Db 1 KPHIDNYLHDKDKDEKIEQYDKNVKEQASKDKKQQAKPQIPKDKSKVAGYIEIPDADIKE 60
Qy 61 PVYPGPATREQLNRGVSFAEENESLDDQNISIAGHTFIGRPNYQFTNLKAAKKGSMVYFK 120
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Db 61 PVYPGPATREQLNRGVSFAEENESLDDQNISIAGHTFIGRPNYQFTNLKAAKKGSMVYFK 120
Qy 121 VGNETRKYKMTSIRNVKPTAVGVLDEQKGKDKQLTLITCDDLNRETGVWETRKILVATEV 180
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Db 121 VGNETRKYKMTSIRNVKPTAVGVLDEQKGKDKQLTLITCDDLNRETGVWETRKILVATEV 180
Qy 181 K 181
|
Db 181 K 181
Prosecution Insights