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 .
Claim Interpretation
Claims 1 and 14 both comprise a method for differentiating a population of B cell lineage and/or precursor cells and both require the use of a basal medium supplemented with either SCF, TPO, or FLT3L and at least one other cytokine. Claim 1 is directed towards a population of CD34+ hematopoietic stem or progenitor cells and a derivation medium, and claim 14 is directed towards a population of B cell precursors with a differentiation medium. Though there is a nuanced difference in the art between “differentiation” and “derivation” and use of B cell precursors with CD34+ hematopoietic stem or progenitor cells, the actual method step comprising contacting the cell population with a basal medium supplemented with either SCF, TPO, or FLT3L and at least one other cytokine is identical within the two claims. Furthermore, both claims use a form of B cell precursor cells which both have the potential to ultimately differentiate into B cells. Therefore, claims 1 and 14 are considered identical regarding rejections applied over prior art, and there is no significant difference between the two claims from a method standpoint as the methods are identical.
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.
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 as of the effective filing date of the claimed invention(s) 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 as of the effective filing date of the later invention 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.
Claim(s) 1, 2, 5, 6, 8, 14, 16, 17, 18, 25, 26, 27, and 43 are rejected under 35 U.S.C. 103 as being unpatentable over Kraus et al. (A Feeder-Free Differentiation System Identifies Autonomously Proliferating B Cell Precursors in Human Bone marrow, 2013) in view of Kouro et al. (In Vitro Differentiation and Measurement of B Cell Progenitor Activity in Culture, 2005)
Regarding claims 1, 5, and 14: Kraus teaches a differentiation protocol to generate the development of B cells from CD34+ hematopoietic stem cells up to the stage of immature IgM+ B cells and does not require the use of feeder cells. (Pg 1044, Abstract) The CD34+ hematopoietic stem cells are cultured in Iscove’s medium, a type of basal medium, supplemented with, in part, stem cell factor (hereafter SCF), FMS-like tyrosine kinase 3 ligand (hereafter FLT3L) and cytokine human IL-6. (Pg 1045, In Vitro Culture) In addition, Kraus established that the HSC precursors expressed both CD10 and CD19 at the beginning of the differentiation process and maintained expression of both throughout the culture process, as shown in figure 1A below:
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Kraus fails to teach use of serum-free culture conditions, as Kraus includes fetal calf serum in the differentiation medium. (Pg 1045, Materials and Methods) Kouro teaches use of a B cell lineage differentiation protocol, specifically Basic Protocol 1, which describes a B lineage differentiation culture system that does not require the use of stromal cells or serum, allowing for the direct effect of added cytokines on the progenitor cells to be assessed. (Pg 1, Introduction)
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to combine the teaching of use of serum free media of Kouro with the culture protocol taught by Kraus to create a B cell differentiation protocol which uses serum free conditions. One skilled in the art would have had motivation and a reasonable expectation of success at doing so based on the teaching of Kouro, who detail that use of serum free media allows for observing the direct effect of added cytokines on the cells in culture.
Regarding claims 2 and 16: Kraus teaches that the CD34+ cells were obtained from a human cord blood sample after cesarian delivery. (Pg 1045, Materials and Methods)
Regarding claim 4: Following the discussion of claim 1, Kraus teaches the use of both SCF and FLT3L in the differentiation media. (Pg 1045, In Vitro Culture)
Regarding claims 6 and 17: Following the discussion of claims 1, 5, and 14, it is shown in Figure 1H that the population of B cells have significantly more CD19 expression at the end of the differentiation process than at the start as shown below:
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Furthermore, it is inherent that the cell population would comprise more CD19 expression at the end of the differentiation protocol than at the start as that is the intended end result of the method step of claims 1 and 5, of which claim 6 depends.
Regarding claims 8 and 18: As can be seen below, a percentage of the CD19+ B lineage cells further comprise IgM expression. Kraus fails to explicitly disclose that the IgM+ cells secrete antibodies, however, this is also inherent as this is one of the intended end results of the method step of claims 1, 5, and 14.
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Regarding claims 25 and 26: Kraus teaches use of IL-6 in the differentiation medium the CD34+ B lineage cells were cultured in. (Pg 1045, In vitro culture)
Regarding claims 27 and 43: Kraus specifies use of a feeder cell free in vitro system for B cell culture and differentiation (pg 1045, Introduction) and states that use of feeder cells (that are often ill-categorized) can interfere with studying the signaling responses and proliferation requirements of human precursor B cells in vitro. (Pg 1044, Introduction)
Claim(s) 10-12 and 19-21 are rejected under 35 U.S.C. 103 as being unpatentable over Kraus et al. (A Feeder-Free Differentiation System Identifies Autonomously Proliferating B Cell Precursors in Human Bone marrow, 2013) in view of Kouro et al. (In Vitro Differentiation and Measurement of B Cell Progenitor Activity in Culture, 2005) in view of Elgueta et al. (Molecular mechanism and function of CD40/CD40L engagement in the immune system, 2009)
The teachings of Kraus and Kouro are discussed above. Both fail to teach use of CD 40 in a downstream differentiation medium.
Regarding claims 10 and 19: Kraus teaches use of a downstream differentiation medium which the CD34+ cells are switched to on day 7 of culture that has, in addition to Iscove’s medium (a basal medium), IL-7, SCF, and FLT3L present in the media. (Pg1045, In vitro culture) Kraus fails to teach use of serum free conditions or use of a ligand of human CD40.
Kouro describes a B lineage differentiation culture system that does not require the use of stromal cells or serum, allowing for the direct effect of added cytokines on the progenitor cells to be assessed. (Pg 1, Introduction) Kouro fails to teach use of a human CD40 ligand.
Elgueta teaches that CD40 and its ligand is involved in B-cell activation and is necessary in cellular and immune functions. (Pg 1-2, Introduction) Furthermore, Elgueta teaches that co-expression of CD40 and its ligand in immortalized human epithelial cells induced an increased rate of proliferation, motility, and invasion. (Pg 14, Direct effect of CD40/CD40L interaction on tumor cells) Elgueta also teaches that blockading of the CD40 ligand gene prevents clonal proliferation of antigen-responding B cells (pg 10,CD40/CF40L interactions in the initiation and progression of the GC (Germinal Center)), making the presence of CD40L essential in B cell culture.
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of Kraus and Kouro with the teachings of Elgueta to create a secondary serum-free culture media comprising CD40L. One skilled in the art would have had motivation and a reasonable expectation of success based on the teachings of Kouro (removal of serum allows the direct effect of added cytokines to the progenitor cells to be addressed) and Elgueta (CD40L is essential for the clonal proliferation of B cells, making it essential for B cell culture.
Regarding claims 11 and 20: As can be seen, following the protocol as taught by Kraus results in obtaining more IgM+ cells post-culture than prior to culture in the downstream differentiation media. Futhermore, this is inherent as it is an intended result of the method step of claim 1, of which claim 10 ultimately depends from.
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Regarding claims 12 and 21: Kraus fails to explicitly disclose that the IgM+ cells secrete antibodies, however, this is also inherent as this is one of the intended end results of the method step of claims 1, 5, and 14.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HANNA M THUESON whose telephone number is (571) 272-3680. The examiner can normally be reached M-F 7:30-5 EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
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/HANNA MARIE THUESON/Examiner, Art Unit 1638
/Tracy Vivlemore/Supervisory Primary Examiner, Art Unit 1638
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