DETAILED ACTION
Status of Application, Amendments and/or Claims
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claims 1-41 are pending.
Election/Restrictions
The elections of (1) IgM+ B cells as the species of undesired cell types, and (2) antibody as the species of target protein, in the reply filed 3/4/26 are acknowledged. Claims 28-32 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected species, there being no allowable generic or linking claim.
Claims 1-27 and 33-41 are under consideration, as they read upon the elected species.
Specification
The disclosure is objected to because of the following informalities:
---The title is not descriptive because it is directed generally to any method of producing antibodies, but the claims are limited to a process comprising 4 specific steps as recited in claim 1. A new title is required that is clearly indicative of the invention to which the claims are directed. The following title is suggested: “Method for Producing Antibodies from Individually Cultured IgG+ B Cells”.
Appropriate correction is required.
Drawings
Corrected drawings in compliance with 37 CFR 1.121(d) are required because Fig. 2A and 2B each include multiple amino acid sequences of four or more residues that are not identified by a sequence identifier as required by the sequence rules.
This application was filed on or after July 1, 2022, and thus is subject to the ST.26 Sequence Requirements. See 37 CFR 1.831, which defines “amino acid sequences” in ¶ (b) as “an unbranched sequence … containing 4 or more specifically defined amino acids, wherein the amino acids form a single peptide backbone”.
Alternately, the requirements can be satisfied by identifying each sequence by the appropriate identifier in the brief description of the figure in the specification.
Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). Applicants are advised to employ the services of a competent patent draftsperson outside the Office, as the USPTO no longer prepares new drawings. The corrected drawings are required in reply to the Office action to avoid abandonment of the application. The requirement for corrected drawings will not be held in abeyance.
Claim Objections
Claims 6 and 7 are objected to because of the following informalities:
In claims 6 and 7, “IgM B cells” should be written as “IgM+ B cells”; compare with “IgG+ B cells” in parent claim 1.
Appropriate correction is required.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-27 and 33-41 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
In claim 1, line 14, refers to “culturing the separated IgG+ B cells of step (b) individually”, but the antecedent basis of this “the separated IgG+ B cells of step (b)” is unclear because step (b) ends with a sample that is enriched for IgG+ B cells.
The remaining claim(s) included in the rejection are dependent claims that depend from one of the claims rejected above, and encompass the same indefinite subject matter.
Claim Rejections - 35 USC § 112(a), written description
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.-The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 26 and 27 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for pre-AIA the inventor(s), at the time the application was filed, had possession of the claimed invention.
Per MPEP 2163, 35 U.S.C. 112(a) requires, “separate and distinct from the enablement requirement”, that the “specification shall contain a written description of the invention…” (Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1355 (Fed. Cir. 2010)). In making a determination of whether the application complies with the written description requirement of 35 U.S.C. 112(a), it is necessary to understand what Applicants are claiming and what Applicants have possession of.
Dependent claims 26 and 27 are directed to the method of screening an antibody of claim 25, in turn depends from claims 1 and 20. Dependent claims 26 and 27 further requires “the CDRs of an anti-gD monoclonal antibody (mAb)” (claim 26) that is “5B6” (claim 27). The specification does not provide any further description of the target of the antibody, gD, but it is presumed to be the protein herpes simplex virus (HSV) glycoprotein gD known in the prior art (e.g., Spear et al, 2006. Virology. 344(1): 17-24).
The prior art recognizes that antibodies bind to epitopes of 5-7 amino acids (Benjamini et al, 1991. Immunology: A Short Course, 2nd edition, page 40 only). The prior art recognizes the gD protein to be 394 amino acids in length (see page 19 of Spear et al, 2006, cited above). Thus, even considering only continuous epitopes, gD comprises a multitude of different regions of five amino acids that can serve as epitopes (e.g., residues 1-5, 2-6, 3-7, up to residues 390-394). While the general structure of an antibody was well-known in the prior art, it is the structure of the complementarity-determining regions (CDRs) that determines the specificity of a particular antibody, and said CDR structure is not predictable based on the epitope to which it binds. Thus, even knowing the structure (CDRs) of one antibody does not allow the skilled artisan to predict the structure of other antibodies that bind to the same epitope or to the other epitopes in the same protein. The relevant art, Ferrara et al (2015. mAbs. 7(1): 32-41) teaches that there is substantial variation in the structure of antibodies that bind to a single protein, on the order of hundreds of different sequences; specifically, see page 36: "The number of different HCDR3s selected against the test antigens ranges from 74 to 460 (Table 3), with the actual number of different antibodies likely to be significantly higher when different VL chains and additional VH mutations are taken into account” (pg 36). Thus, there are at least hundreds of different antibody structures that bind to the multitude of epitopes found in the 394 amino acids of the HSV gD protein.
Thus, the claims are genus claims because they encompass use of a genus of antibody structures having the required functionality, i.e., being “anti-gD”, which means binding to gD. However, a product defined by function is not in and of itself sufficient to describe the product because it is only an indication of what the product does, rather than what it is; i.e., the specific structure of the product. It is only a definition of a useful result rather than a definition of what achieves that result. Per MPEP 2124, "describing a composition by its function alone typically will not suffice to sufficiently describe the composition". Furthermore, in the instant case the specification does not establish a correlation between structure and function; i.e., the structure of one anti-gD antibody does not provide predictability regarding other antibody structures having the same functionality. Furthermore, the decision of the Federal Circuit in Amgen v. Sanofi, 872 F.3d 1367 (Fed. Circ. 2017) held that a claim directed to an antibody requires written description of the antibody itself rather than being satisfied solely by a written description of the antigen to which it binds (the so-called "newly characterized antigen" test). Thus, a description of the target protein (e.g. gD) is not in and of itself sufficient to provide a description of the genus of antibodies binding to said target.
Written description for a genus may also be satisfied through sufficient description of a relevant number of species. This is dependent on whether one of skill in the art would recognize necessary common attributes or features possessed by the members of the genus. Generally, in an unpredictable art, adequate description of a genus which embraces widely variant species cannot be achieved by disclosing only one species within the genus. Also, “[w]hen a patent claims a genus using functional language to define a desired result, the specification must demonstrate that the applicant has made a generic invention that achieves the claimed result and do so by showing that the applicant has invented species sufficient to support a claim to the functionally-defined genus" (Capon v. Eshhar, 418 F.3d 1349 (Fed. Cir. 2005)). “[A] sufficient description of a genus … requires the disclosure of either a representative number of species falling within the scope of the genus or structural features common to the members of the genus so that one of skill in the art can 'visualize or recognize' the members of the genus” (AbbVie, 759 F.3d at 1297, reiterating Eli Lilly, 119 F.3d at 1568-69).
In support of the genus of antibodies binding to gD, the specification points to one example, which is termed “5B6” and stated to be made by Genentech (¶ 149). However, Genentech is the Applicant of the instant application, and the specification does not teach if this antibody is commercially available to the public. Furthermore, even if the antibody is demonstrated to commercially available, claims 26 and 27 require use of the CDRs of this antibody, and the specification fails to describe the sequences of the CDRs of 5B6 such that the claimed method can be practiced with use of an antibody comprising these CDRs. Thus, the disclosure of the name “5B6” is not considered to be sufficient to meet the written description requirement with respect to this species of antibody. As such, it is considered that the instant specification does not provide a sufficient written description of any species of anti-gD antibody.
Per MPEP 2163, "A "representative number of species" means that the species which are adequately described are representative of the entire genus. Thus, when there is substantial variation within the genus, one must describe a sufficient variety of species to reflect the variation within the genus. See AbbVie Deutschland GmbH & Co., KG v. Janssen Biotech, Inc., 759 F.3d 1285, 1300, 111 USPQ2d 1780, 1790 (Fed. Cir. 2014) (Claims directed to a functionally defined genus of antibodies were not supported by a disclosure that "only describe[d] one type of structurally similar antibodies" that "are not representative of the full variety or scope of the genus.")
Vas-Cath Inc. v. Mahurkar, 19USPQ2d 1111 (Fed. Cir. 1991), clearly states “applicant must convey with reasonable clarity to those skilled in the art that, as of the filing date sought, he or she was in possession of the invention. The invention is, for purposes of the ‘written description’ inquiry, whatever is now claimed” (pg 1117). The specification does not “clearly allow persons of ordinary skill in the art to recognize that [he or she] invented what is claimed” (pg 1116).
Therefore, the method of dependent claims 26 and 27 fails to meet the written description requirement with respect to the CDRs of the anti-gD antibodies required for use by these claims. Applicants are reminded that Vas-Cath makes clear that the written description provision of 35 U.S.C. §112 is severable from its enablement provision (pg 1115).
Note on Prior Art Rejection(s)
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 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 § 103
The following is a quotation of 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action:
(a) A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived by the manner in which the invention was made.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned at the time any inventions covered therein were effectively filed absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned at the time a later invention was effectively filed in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-2, 4-7, 9-10, 18-19, 33-36, 40 and 41 are rejected under 35 U.S.C. 103(a) as being unpatentable over Carbonetti et al, 2017. Journal of Immunological Methods 448: 66-73 (cited on the 3/4/26 IDS), and further in view of Wenzel et al, 2020 (Chapter 8 of “Genotype Phenotype Coupling: Methods and Protocols”, Methods in Molecular Biology, vol. 2070, Spring Science+Business Media, LLC. First Online: 18 October 2019 per https://link.springer.com/protocol/10.1007/978-1-4939-9853-1_8). The earliest date to which the instant application claims priority is 8/31/20.
Claim 1 encompasses a method of identifying an antibody that binds to a desired region of a target protein, which comprises four steps:
(a) providing a sample containing IgG+ B cells from an animal that has been immunized with the target;
(b) enriching the sample for the IgG+ cells by separating them from undesired cell types via two sub-steps: (i) contacting the sample with a tagged antibody that binds an undesired cell type and (ii) contacting the sample with a surface having affinity for the tag to remove the undesired cell types;
(c) culturing the separated IgG+ B cells individually; and
(d) identifying IgG+ B cells that produce antibodies that bind to the desired region of the target protein by assessing the affinity of the supernatants for (i) the target protein; and (ii) a control protein comprising a non-target protein; wherein binding to (i) but not (ii) identifies the B cells that bind the desired region of the target protein.
Carbonetti teaches “A method for the isolation and characterization of functional murine monoclonal antibodies by single B cell cloning” (see title). This method includes harvesting a splenocyte sample from a mouse immunized with a target protein (PfTRAP) (page 68), which meets step (a) of claim 1. The sample was “passed through a negative B cell selection column (StemCell Technologies, Inc., Tukwila, WA, USA), removing CD4+ and CD8+ T cells”, resulting “in a cell population that was approximately 97% B cells” (page 68). In the supplementary material, referenced on page 72 of Carbonetti, this column is disclosed as StemCell catalog # 19754, “EasySep negative selection mouse B cell enrichment kit.” (see page 1 of “Supplementary Material 2” for Carbonetti et al, 2017; 7 pages as printed; available on ScienceDirect.com at
https://www.sciencedirect.com/science/article/pii/S0022175917300674). This column relies on contacting the sample with biotinylated antibodies, and removing the bound cells with beads (see page 2 of EasySep Negative Selection Mouse B Cell Enrichment Kit product sheet, StemCell Catalog #19754, August 2011, 2 pages; cited here to provide evidence of an inherent feature of the product used by Carbonetti), which meets the limitations of using tagged antibodies and a surface having affinity for the tag as required by step (b) of claim 1. The reduction in T cells encompasses enrichment of B cells, including IgG+ cells, as required by step (b) of claim 1. Carbonetti further teaches sorting the B-cells, and then “culturing sorted B cells” (page 68), which meets the limitations of step (c) of claim 1. The “culture supernatant” was then tested “for antigen binding by capture ELISA” (page 68), which meets the limitations of step (d), except that it does not include an assessment of the affinity of the supernatant for a control protein comprising a non-target protein as required by part (ii) of step (d).
Wenzel teaches a protocol for screening antibodies to “analyze the antigen specificity” (page 150), including identifying “positive candidates with a signal (on antigen) 10x over noise (on control protein, e.g., streptavidin or BSA)” (page 151). Such a control protein meets the limitation of a “non-target protein” as recited in step (d)(ii) of claim 1.
It would have been obvious to the person of ordinary skill in the art before the effective filing date of the claimed invention to take the method of identifying antibodies taught by Carbonetti and modify said method to include an assay of the culture supernatant of the cultured B-cells for binding to a control protein as taught by Wenzel, and wherein the selected antibody is on that binds to the target protein but not the control protein. The person of ordinary skill in the art would have been motivated to add such an assay to improve the selected antibodies by choosing only those that have a strong signal (binding target) over noise (binding control). The person of ordinary skill in the art would have had a reasonable expectation of success in making the modification because the teachings of Wenzel are generally suggested for antibodies to any antigen of interest. This rationale supports a prima facie conclusion of obviousness in accord with KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Claim 2 encompasses a method of claim 1 wherein the animal is a rabbit. Carbonetti further teaches that single B cell isolation is “translatable across species”, including rabbits” (page 67). As such, it would further have been obvious to modify the method obvious over the teachings of Carbonetti in view of Wenzel for use with rabbits.
Claim 4 encompasses a method of claim 1 wherein the animal has been immunized for “about 8 weeks”. The instant specification does not provide a limiting definition of the term “about”; as such, the term “about 8 weeks” is interpreted broadly as encompassing the immunization protocol taught by Carbonetti, which was “three intramuscular injections spaced two weeks apart” followed by splenocyte harvesting 48-72 hours later (page 68). As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claim 4.
Claim 5 encompasses a method of claim 1 wherein the sample has been processed to remove macrophages and monocytes. The EasySep column used by Carbonetti purifies the splenocyte population to 97% B cells (page 68), and thus depletes the population of macrophages and monocytes, among other cell types. As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claim 5.
Claims 6 and 7 encompass a method of claim 1 wherein the undesired cell types are T cells (claim 6) and the one or more antibody fragments that bind to T cells are anti-T-lymphocyte antibodies that bind T-lymphocytes (claim 7). In the teachings of Carbonetti set forth above, the undesired cell types are T-cells, and the antibodies bind to the T-cells. As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claims 6 and 7.
Claims 9 and 10 encompass a method of claim 1 wherein the surface is a bead (claim 9) that is a magnetic bead (claim 10). In the teachings of Carbonetti set forth above, the surface is a magnetic bead. As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claims 9 and 10.
Claim 18 encompasses a method of claim 1 wherein step (d) includes an ELISA for assessing the affinity of the supernatants. In the teachings of Carbonetti set forth above, the affinity of the culture supernatant for antigen is assessed by ELISA. As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claim 18.
Claim 19 encompasses a method of claim 1 that further comprises cloning the VH and VL regions of one or more IgG+ B cells that have been identified. Carbonetti further teaches cloning of Ig sequence including the VH and VL regions (section 2.6, Figure 2). As such, it would have further been obvious to clone the VH and VL regions of the selected antibody when practicing the method obvious over the teachings of Carbonetti in view of Wenzel described above.
Claim 33 encompasses a method of claim 1 wherein a plurality of antibodies to the target are produced, with “plurality” broadly encompassing two or more. Carbonetti further teaches that the capture ELISA identified multiple culture supernatants that bound to target antigen by capture ELISA (page 70; Figure 4), of which 6 were selected for cloning (page 71, Table 3). As such, it would have further been obvious to produce multiple antibodies when practicing the method obvious over the teachings of Carbonetti in view of Wenzel described above.
Claim 34 encompasses a method of claim 1 wherein the plurality of antibodies produced is at least 100. The capture ELISA results shown by Carbonetti included over 50 culture supernatants comprising target antigen-binding antibodies (see Figure 4). Of these, six antibodies were further characterized, and found to bind the target antigen with different affinities (Table 3) and “likely recognize different epitopes” (page 72). It would have further been obvious to scale up the size of the experiment of Carbonetti, e.g., double the size, thus producing over 100 culture supernatants comprising target antigen-binding antibodies, in order to identify more antibodies binding to the target antigens. As such, the further limitations of the method of claim 34 are also obvious over the teachings of Carbonetti in view of Wenzel.
Claim 35 encompasses a method of claim 33 wherein at least 50% of the antibodies produced are unique. Carbonetti further teaches that out of “six selected culture wells”, “six unique, recombinant mAbs” were retrieved and produced (page 71). As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claim 35.
Claim 36 encompasses a method of claim 36 wherein the plurality of antibodies binds the target with KD of about 200 nM (2.0 x 10-7 M) or lower. Carbonetti further teaches that the six selected antibodies “exhibited a range of KD values, varying from 9.73 x 10-9 to 1.40 x 10-7 M)” (page 71), each of which is encompassed by “about 200 nM or lower”. As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claim 36.
Claim 40 limits the method of claim 1 by means of a further “wherein” clause. This clause has been fully considered in context of the entire claim, but does not render the claimed method patentably distinct from a method taught by the prior art because it simply expresses the intended result of a process step positively recited. See MPEP 2111.04, which states that a "whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited" (Hoffer v. Microsoft Corp., 405 F.3d 1326, 1329, 74 USPQ2d 1481, 1483 (Fed. Cir. 2005), quoting Minton v. Nat ’l Ass ’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)). Specifically, in claim 40, the further limitation simply expresses the intended result (increased viability of IgG+ B cells) of a process step positively recited (enriching for IgG+ cells). As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claim 40.
Claim 41 encompasses a method of claim 19 wherein the steps are performed within 12 weeks. Carbonetti further teaches that “This protocol can be completed in ~20 days after the immunization protocol ends” (page 71), and further teaches that the immunization was “three intramuscular injections spaced two weeks apart” (page 68) (i.e., 4 weeks total), and splenocyte harvesting followed this by 48-72 hours (page 68), bringing the total time to well under 12 weeks. As such, the method obvious over the teachings of Carbonetti in view of Wenzel described above also meets the limitations of claim 41.
Claims 3 and 11-17 are rejected under 35 U.S.C. 103(a) as being unpatentable over Carbonetti et al, 2017 (fully cited above and on the 3/4/26 IDS), and further in view of Wenzel et al, 2020 (fully cited above), as applied to claim 1 above, and further in view of Endl et al, U.S. Patent Application Publication 20130084637, published 4/4/13.
Claim 3 encompasses a method of claim 1 wherein the sample is a blood sample. The teachings of Carbonetti described above for claim 1 are limited to use of spleen cells, and does not teach use of blood, and neither does Wenzel.
Endl teaches methods for “isolation of a B-cell from a population of B-cells”, where the isolated cells are “antibody-producing cells” and the “binding specificity of the antibodies can be determined” (¶ 5). Endl teaches that such B-cells can be “obtained from the blood of an experimental animal” but can also be “obtained from the spleen” (¶ 96). It would have further been obvious to the person of ordinary skill in the art before the effective filing date of the claimed invention to take the modified method of Carbonetti in view of Wenzel that meets the limitations of claim 1 and further modify the method to use blood cells as taught by Endl in place of splenocytes as taught by Carbonetti, because Endl teaches that single B-cells can be isolated from either source, and thus such a change represents a simple substitution of one prior art disclosed sample for another. This rationale supports a prima facie conclusion of obviousness in accord with KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Claims 11 and 12 encompass a method of claim 1 wherein step (b) further comprises a third step (step b(iii)) of contacting the enriched sample with an antibody that comprises a first marker and binds to IgG+ B cells and an agent that identifies viable cells (claim 11) and further wherein the antibody is an anti-IgG antibody and/or the agent is propidium iodide (claim 12). The goal of the method of Carbonetti described above for claim 1 is to identify B-cells that secrete IgG; i.e., B-cells that are IgG+ (page 71), and Carbonetti further teaches contacting the enriched sample with antibodies for single B-cell sorting by FACS (section 2.3), but these antibodies do not include an anti-IgG antibody, and Carbonetti instead uses an anti-IgG antibody to detect IgG production after culturing of the cells (page 68). Carbonetti further does not teach include an agent for identifying viability of the cells such as propidium iodide, instead using “[s]oluble immunoglobulin (Ig) production” as a “proxy for cell survival/proliferation in B cell culture” (page 70).
Endl teaches methods of selecting single B-cells by contacting a cell sample with antibodies for single B-cell sorting by FACS (¶ 87). Endl teaches use of an anti-IgG+ antibody to label IgG+ B-cells that comprises the maker FITC (¶ 82, Table 5) and use of propidium iodide to distinguish dead cells (¶ 188).
It would have further been obvious to the person of ordinary skill in the art before the effective filing date of the claimed invention to take the modified method of Carbonetti in view of Wenzel that meets the limitations of claim 1 and further modify the method to include use of an anti-IgG antibody taught by Endl as part of the single cell sorting by FACs, and further to include use of propidium iodide to determine cell viability as taught by Endl. The person of ordinary skill in the art would have been motivated to also use an anti-IgG antibody as taught by Endl in order to improve the method by only selecting single cells that are IgG+ during FACS, and thus improve the selection of cells secreting IgG for culturing and assaying. The person of ordinary skill in the art would have been motivated to also use propidium iodide in order to accurately determine cell viability prior to selecting the cells for culturing. The person of ordinary skill in the art would have had a reasonable expectation of success in applying the permutations taught by Endl to that of the modified method of Carbonetti in view of Wenzel because both the teachings of Carbonetti and Endl are both in the field of isolation of single B-cells for identification of antibodies, and thus the skilled artisan would reasonably expect the permutations of one protocol to be applicable to another. This rationale supports a prima facie conclusion of obviousness in accord with KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Claims 13-17 depend from claim 11 and add the following further limitations: wherein step b(iii) further includes contacting the sample with the target protein comprising a second marker (claim 13) and further with a control protein comprising a third marker (claim 14) and further wherein the first, second and third marker are fluorescent markers (claim 15), and further wherein step (b) comprises a fourth step (step b(iv)) wherein cells are isolated that are identified as viable by the agent that identifies viable cells and that comprise the first and second marker, but not the third marker (claim 16), and further wherein the isolating is by FACS (claim 17). As part of the FACs sorting for individual B-cells, Carbonetti further teaches contacting the cell sample with a target stain and a decoy stain (page 68), each of which comprises a different fluorescent marker for sorting by FACS, and thus meet the limitations of the second and third marker of claims 13-17. As such, it would have further been obvious to use such when practicing the method obvious over the teachings of Carbonetti in view of Wenzel and Endl set forth above for parent claim 11.
Claim 8 is rejected under 35 U.S.C. 103(a) as being unpatentable over Carbonetti et al, 2017 (fully cited above and on the 3/4/26 IDS), and further in view of Wenzel et al, 2020 (fully cited above), as applied to claim 1 above, and further in view of EasySep Negative Selection Mouse Pan-B Cell Isolation Kit product sheet. StemCell Catalog #19844. 2019. Pages 1-3.
Claim 8 encompasses a method of claim 1 wherein the antibodies that bind to the one or more undesired cell types comprise a biotin tag and the surface comprises streptavidin.
As described above for parent claim 1, the B-cell separation column used by Carbonetti employs biotinylated-tagged antibodies to bind B-cells, followed by separation of these cells by beads with affinity for the biotin tag. The surface in this kit comprises dextran, binds to the biotinylated antibodies via a bispecific antibody complex (see page 3 of the EasySep Negative Selection Mouse B Cell Enrichment Kit product sheet cited above). The column does not use a bead comprising streptavidin.
The Pan-B Cell Isolation Kit (2018) is also a negative selection kit, which is described as being used for isolating “untouched and highly purified pan-B cells”, including “plasma cells” (which secreted antibodies) “from mouse splenocytes by immunomagnetic negative selection” (page 1). The kit is further described as targeting “non-pan-B cells for removal with biotinylated antibodies recognizing specific cell surface markers” (page 1). The “[u]nwanted cells are labeled with biotinylated antibodies and streptavidin-coated magnetic particles, and separated without columns using an EasySep magnet”, with the “[d]esired cells” being “simply poured off into a new tube”, and the “[i]solated cells” being “immediately available for downstream applications such as flow cytometry, culture, or cell-based assay” (page 1).
It would have further been obvious to the person of ordinary skill in the art before the effective filing date of the claimed invention to take the modified method of Carbonetti in view of Wenzel that meets the limitations of claim 1 and further modify the method to use the Pan-B Cell Isolation Kit (2018) in place of the negative B cell selection column used by Carbonetti. The person of ordinary skill in the art would have been motivated to make this change in order to take advantage of the improved properties taught by the Pan-B Cell Isolation Kit, including separation without using a column and immediately availability of the cells for further use. The person of ordinary skill in the art would have had a reasonable expectation of success because the change simply requires substituting one B-cell isolation kit for another. This rationale supports a prima facie conclusion of obviousness in accord with KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Claims 20-25 and 37 are rejected under 35 U.S.C. 103(a) as being unpatentable over Carbonetti et al, 2017 (fully cited above and on the 3/4/26 IDS), and further in view of Wenzel et al, 2020 (fully cited above), as applied to claims 1 and 33 above, and further in view of Hauskins et a, WO 2018/023100, published 2/01/2018.
Claims 20-25 encompass a method of claim 1 wherein the target protein is an antibody (claim 20) and further wherein the desired region of the antibody is a CDR (claim 21), or further wherein the animal has been immunized with a fragment (claim 22) that is an antigen-binding fragment (claim 23), or further wherein the one or more undesired binding sites of the target are the one or more framework regions (claim 24), or further wherein the control protein is a Fab fragment comprising a light and heavy chains comprising framework regions having at least 85% identity to the light and heavy framework regions of the target, and each having a set of irrelevant CDRs (claim 25). Claim 37 encompasses a method of claim 33 wherein the target protein is an antibody and the plurality of antibodies comprise at least one antigen-blocking antibody.
Carbonetti further teaches that the methods that they teach “can be applied to a wide array of protein antigens” (see Abstract) and that “[o]ur findings show that this modular protocol will be useful for the rapid generation of mAbs and should be effective for a variety of target antigens and multiple per-target specificities” (page 67) but does not specifically teach that the target antigen is an antibody.
Hauskins teaches methods for producing anti-idiotype antibodies that recognize anti-CD19 antibodies. Hauskins defines an “anti-idiotype antibody” as “an antibody, including antigen-binding fragments thereof, that specifically recognizes, is specifically targeted to, and/or specifically binds to an idiotope of an antibody, such as an antigen-binding fragment” (¶ 125). Hauskins further teaches “a method of identifying an anti-idiotype antibody or antigen-binding fragment including (a) introducing into a subject a soluble immunization reagent containing an antigen-binding fragment of the target antibody fused to a solubilizing moiety; and (b) identifying an antibody from the subject that specifically binds to the target antibody or the antigen-binding fragment thereof” (¶ 68). Hauskins further teaches that the anti-idiotype antibodies “does not bind to a reference antibody”, including one that “binds to the same antigen as the target antibody” and comprises framework regions having at least 90% identity to the corresponding framework regions of the target antibody (¶ 228). Hauskins further teaches that the antibody can be an antagonist by “preventing the association” of antibody and antigen (¶ 412).
It would have been obvious to the person of ordinary skill in the art before the effective filing date of the claimed invention to take the modified method of Carbonetti in view of Wenzel that meets the limitations of claim 1 and further modify the method to apply it to an antigen that is an antibody as taught by Hauskins. The person of ordinary skill in the art would have been motivated to make this change in order to generate an anti-idiotype antibody that binds to an antibody of interest, and would be motivated to apply the advantages taught by Carbonetti for their protocol such as fast generation of mAbs with multiple per-target specificities, and would have had a reasonable expectation of success because Carbonetti teaches that the protocol is applicable to a variety of target antigens and thus would be expected to work with a target antigen that is an antibody. This rationale supports a prima facie conclusion of obviousness in accord with KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Claims 38-39 are rejected under 35 U.S.C. 103(a) as being unpatentable over Carbonetti et al, 2017 (fully cited above and on the 3/4/26 IDS), and further in view of Wenzel et al, 2020 (fully cited above), as applied to claims 1 and 33 above, and further in view of Hauskins et a, WO 2018/023100, published 2/01/2018, as applied to claim 37 above, and further in view of “What is an Anti-Idiotopic Antibody?”, 2018 (Jan 19), GenScript webpage, 5 pages as printed, no author listed, available at https://www.genscript.com/antibody-news/what-is-an-anti-Idiotypic-antibody.html.
Claims 38 and 39 encompass a method of claim 33 wherein the target protein is an antibody and the plurality of antibodies comprise at least one antigen non-blocking antibody (claim 38) and further wherein the antibody binds to an antigen-antibody complex (claim 39).
The modified method obvious over the teachings of Carbonetti in view of Wenzel and further in view of Hauskins that meets the limitations of claim 37 is set forth above. While Hauskins teaches an anti-idiotype antibody that is an antagonist antibody, Hauskins does not teach an anti-idiotype antibody that is a non-blocking antibody, or a non-blocking antibody that binds to an antigen-antibody complex.
The GenScript webpage teaches that there are three types of anti-idiotype (anti-ID) antibodies: “A: Antigen Blocking Anti-ID Antibody”, “B: Non-Blocking Anti-ID Antibody”, and “C: Complex Specific Anti-ID Antibody” (page 1). The webpage further teaches that second type can be “used to detect all forms of available antibody drug (free and antigen bound)” and third type will detect the antibody only when bound to antigen (page 1).
It would have been obvious to the person of ordinary skill in the art before the effective filing date of the claimed invention to take the modified method of Carbonetti in view of Wenzel that meets the limitations of claim 1 and further modify the method to apply it to an antigen that is an antibody as taught by Hauskins, and further modify it to select an anti-idiotype antibody that binds to the antigen-antibody complex as taught by the GenScript webpage. The person of ordinary skill in the art would have been motivated to make the further change in order to produce an anti-idiotype antibody that binds to the antigen-antibody complex for purposes of measuring the amount of antigen-antibody complex, and would have had a reasonable expectation of success in selecting such an antibody because the teachings of the GenScript page are directed to anti-ID antibodies in general (i.e., directed to any antigen) and thus would be expect to be applicable to a variety of target antigens. This rationale supports a prima facie conclusion of obviousness in accord with KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Conclusion
No claims are allowable.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ZACHARY C HOWARD whose telephone number is (571)272-2877. The examiner can normally be reached on Monday to Friday from 9 AM to 5 PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Vanessa Ford, can be reached at telephone number (571) 272-0857. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ZACHARY C HOWARD/Primary Examiner, Art Unit 1674
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