DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application is being examined under the pre-AIA first to invent provisions.
Applicant’s amendments to the claims dated 1/30/25 are acknowledged. Claims 1-35 are cancelled. Claims 36-45 are new. Prosecution on the merits commences for claims 1-35.
PRIORITY
The instant application, filed 6/13/2024, is a CONTINUATION of US Application No. 12/134,813, filed 6/06/2008 (now abandoned), which claims priority to US Provisional Application No. 60/942,716, filed 6/08/2007.
CLAIMS
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Independent claim 36 is directed to a method of selecting erythropoietin producing cells using magnetic activated cell sorting using an anti-EPO antibody:
Claim Rejections - 35 USC § 103
The following is a quotation of pre-AIA 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, 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 negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under pre-AIA 35 U.S.C. 103(a) 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.
This application currently names joint inventors. In considering patentability of the claims under pre-AIA 35 U.S.C. 103(a), the examiner presumes that the subject matter of the various claims was commonly owned at the time any inventions covered therein were made absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and invention dates of each claim that was not commonly owned at the time a later invention was made in order for the examiner to consider the applicability of pre-AIA 35 U.S.C. 103(c) and potential pre-AIA 35 U.S.C. 102(e), (f) or (g) prior art under pre-AIA 35 U.S.C. 103(a).
Claims 36-45 are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Clayton et al. Cells Isolated from Human Cortical Interstitium Resemble Myofibroblasts and Bind Neutrophils in an ICAM-1-Dependent Manner. Journal of the American Society of Nephrology, 1997. 8(4):604-615, in view of US Patent Application No. 2007/0078084 to Keshore and US Patent No. 6,190,870 to Schmitz.
Clayton discloses methods of selecting normal renal cortical fibroblast (RCF) cells within a heterogeneous mixture of kidney cells via magnetic separation (Abstract, page 605, 608). Clayton teaches the kidney cells are heterogeneous explants from human kidney cortex at nephrectomy cultured in vitro prior to selection (Abstract, page 605, 608).
Clayton discloses the method comprises providing a suspension of heterogeneous kidney cells, incubating the cells with a separation (primary) antibody specific for extracellular antigen CD90 for a time sufficient to label the antigen, pelleting (via centrifugation) and washing the cells, and resuspending the cells in a medium comprising a secondary antibody conjugated (covalently bound) to a magnetic particle, wherein the secondary antibody binds the primary antibody, and applying the magnetically labeled cells to a magnetic separation column (miniMacs) (page 605). Following selection, Clayton expands the normal RCFs in optimized culture conditions (page 605, 609-611, FIG. 5).
Clayton teaches renal cortical fibroblasts are often significantly increased in renal disease, but their role in the development of the disease is unclear because there are few normal RCFs to compare them to. Clayton teaches normal kidney tissue comprises few renal cortical fibroblasts, are they are difficult to isolate and maintain in vitro (abstract, pages 604, 611). Clayton also teaches previous normal renal cortical fibroblasts cultures have large percentages of other kidney cells or are modified cells, and data derived from such cultures may be influenced as a result (page 611, 614).
Clayton teaches the method using magnetic separation using a single antigen against CD90 and optimized culture conditions results in a selected population of normal renal cortical fibroblasts (RCF) with >95% viability that did not reduce the cell’s proliferation rate. Clayton teaches the selected population of normal RCFs comprises sufficient concentrations for characterization, is not transformed and is significantly reduced of heterogeneity compared to previous methods (pages 605, 611). Clayton acknowledges CD90 is a fibroblast marker in other tissues, is not a universal fibroblast marker, and subsets of CD90-negative populations of renal fibroblasts may exist (Table 3, page 614). Thus Clayton establishes kidney cells can be selected against a specific antigen from a heterogeneous kidney population using a metal activating cell sorting process (page 610-611, Discussion).
Thus, with regard to claim 36, Clayton teaches a method of selecting renal fibroblast cells, said method comprising of:
(a) providing a heterogeneous suspension of kidney cells;
(b) centrifuging the heterogeneous suspension to form a cell pellet;
(c) adding to the cell pellet a solution comprising a primary antibody that binds to surface antigen CD90 to form a first antibody-bound cell solution;
(d) adding to the first antibody-bound cell solution a solution comprising a secondary antibody that binds to the primary antibody to form a second antibody-bound solution, wherein the secondary antibody is covalently bound to a magnetic microbead; and
(e) selecting CD90-positive renal fibroblast cells from the second antibody-bound solution using a magnet.
However, Clayton does not disclose wherein the method selects erythropoietin (EPO)-producing cells, or that the primary first antibody is an anti-EPO antibody as required by instant claim 36.
Kishore teaches erythropoietin-producing peritubular fibroblast-like cells (PTFBLC) are a subset of resident kidney fibroblasts responsible for producing erythropoietin (EPO), and are identified by surface expression of CD73 and intracellular EPO (para. [0004], [0028]-[0030], [0278]). Kishore generates cultures of proliferating, erythropoietin-producing PTFBLC in vitro (para. [0004],[0075], [0080], [0082]-[0084], [0104], [0202], [0248], [0270], Examples 6-7). The method comprises harvesting a kidney cortical sample from a subject, co-culturing the PTFBLC, proximal tubular cells, and epithelial cells to produce EPO -producing PTFBLC according to techniques known in the art (para. [0047], [0082]-[0083], [0124], [0190], [0269]-[0270], [0300]). The EPO-producing PTFBLC cells can be maintained in culture as a source of EPO, to study the mechanism of PTFBLC proliferation and EPO secretion, or transplanted into a subject for the in vivo generation of EPO to treat a disease (para [0085],[0124]-[0126], [0129]-[0130], [0137], [0188], [0190], [0196]-[0197], Examples 6-7). CD73 and EPO expression is detected via anti-CD3 and anti-EPO primary antibodies (para. [0202], [0264], [0278], [0300]).
Schmitz discloses methods of selecting cells against tissue specific extracellular or intracellular antigens within a heterogeneous mixture via magnetic separation (Abstract, col. 1, line 35 – col. 2, line 24, col. 3, lines 3-15, 40-46, col. 4, lines 1-60, col. 7, line 55 - col. 8, line 57). Schmitz discloses magnetic separation utilizing intracellular ligands is similar to that of extracellular ligands, however, the cells must be permeabilized prior to incubating the cells with a solution comprising a separation (primary) antibody specific for the intracellular antigen (Abstract, col. 3, lines 1-15, col. 6, line 44 – col. 7, line 55). Schmitz teaches the during labeling steps, washing the cells can occur between each step (col. 7, lines 1-21). Schmitz teaches increases in purity of the selected cells can be accomplished by selecting against more than one tissue specific marker, or repeating the magnetic separation process (col. 8, lines 7-30).
It would have been obvious to combine the methods of Clayton, Kishore and Schmitz to arrive at a process of magnetic selection to select EPO-producing renal fibroblasts using a primary antibody against EPO for in vitro culture as claimed. Clayton discloses magnetic selection of extracellular CD90-positive renal fibroblasts from kidney cortex explanted cultures results in a selected population normal fibroblasts with reduced heterogeneity and sufficient concentrations for in vitro manipulations, but acknowledges other subsets of renal fibroblasts may exist. Kishore teaches erythropoietin-producing peritubular fibroblast-like cells (PTFBLC) are a subset of resident kidney fibroblasts responsible for producing erythropoietin (EPO), identified by surface marker CD73 and intracellular marker EPO, and wherein PTFBLC populations can be produced from kidney tissue explants according to techniques in the art. Schmitz discloses magnetic selection of cells from heterogenous populations can target either extracellular antigens or intracellular antigens, and purity can be increased by selecting against two different antigens. A skilled artisan would have had a reasonable expectation of success in practicing the claimed invention because use of magnetic selection of renal fibroblasts, EPO-positive renal fibroblasts, and as how to utilize magnetic selection protocols against extracellular or intracellular antigens were known at the time of the invention.
With regard to claim 37, Clayton does not disclose performing a second incubation in a solution of primary antibody prior to incubating with the secondary antibody as claimed. However Schmitz teaches incubation of the heterogeneous cells with the primary antibody should be formed for a sufficient time and at a sufficient concentration so that the lack of primary antibody does not reduce the efficiency of the selection (column 7, lines 5-13). Schmitz also teaches repeating the selection step in order to increase the purity of the selected cells (col. 8). Schnitz thus recognizes the saturation of primary antibody on the target antigen in the heterogeneous population is important to prevent reduction in efficiency, and repeating the selection step to increase yield. Schmitz also discloses the solution of heterogenous cells can additionally be treated with the immunohistochemistry reagents during the initial labeling (prior to selection), by treating the cells with the same antibody used as the capture antibody, in order to analyze the cells after selection (col. 6, lines 10-35). Thus, it would have been obvious to repeat the incubation of the cells in a solution of primary antibody, 1) either to ensure saturation of available antigen to prevent reduction in efficiency, or to label cells for later analysis.
With regard to claims 38-39 and 45, Clayton teaches the kidney cells are cultured explants from human kidney cortex at nephrectomy (Abstract, page 605, 608).
With regard to claim 40, Clayton discloses the washing the cells incubated in the primary and/or secondary antibody solutions were washed 1-2 times (page 605).
With regard to claims 41-42, Clayton discloses the cells were incubated with the primary solution for at least 15 minutes at 4oC (page 605).
With regard to claims 43-44, Clayton discloses the cells stained with the primary antibody were incubated with the secondary antibody solution for at least 15 minutes at 4oC (page 605).
Conclusion
No claims are allowed.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KIMBERLY A ARON whose telephone number is (571)272-2789. The examiner can normally be reached Monday-Friday 9AM-5PM.
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KAA
/CHRISTOPHER M BABIC/Supervisory Patent Examiner, Art Unit 1633
