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 .
Election/Restrictions
Applicant’s election without traverse of Invention I; claims 1-7, 11-17, and 23; drawn to a method of making a fluorescently labeled lentiviral vector and the species 4; claims 1-4, 12, and 16; in the reply filed on April 28, 2026 is acknowledged.
Applicant has canceled claims 5-7, 11, 13-15, and 17-23.
Claims 1-4, 12, and 16 are examined on the merits.
Priority
Applicant’s claim for foreign priority to Chinese patent application CN202310295684.1 filed on March 24, 2023 is acknowledged. Receipt is acknowledged of certified copies of papers received in the original language as required by 37 CFR 1.55.
Information Disclosure Statement
It is noted that Applicant has not filed an Information Disclosure Statement (IDS) for the instant case.
Objections to the Drawings
The drawings are objected to because:
FIGs. 5A and 5B appear to indicate fluorescent images while the images are in black and white See also Para. [0027] of the instant specification.
FIG. 7 appears to indicate fluorescent images while the images are in black and white. See also Para. [0029] of the instant specification.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. 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). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Color photographs and color drawings are not accepted in utility applications unless a petition filed under 37 CFR 1.84(a)(2) is granted. Any such petition must be accompanied by the appropriate fee set forth in 37 CFR 1.17(h), one set of color drawings or color photographs, as appropriate, if submitted via the USPTO patent electronic filing system or three sets of color drawings or color photographs, as appropriate, if not submitted via the via USPTO patent electronic filing system, and, unless already present, an amendment to include the following language as the first paragraph of the brief description of the drawings section of the specification:
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
Color photographs will be accepted if the conditions for accepting color drawings and black and white photographs have been satisfied. See 37 CFR 1.84(b)(2).
Objections to the Specification
The disclosure is objected to because of the following informalities: the instant specification recites a four plasmid packaging system which comprises “pGap/pol” in at least Paras. [0011], [0012], and [0013]. The term “pGap/pol” appears to be a typographic error. The term pGap/pol has been interpreted as intending to refer to “pGag/pol”. Appropriate correction is required. See MPEP 2163.07(II).
Claim Objections
Claims 1-4 are objected to because of the following informalities:
Claim 1 recites abbreviations for N3-LVs and Cy5-LVs prior to defining the abbreviations. Appropriate correction is required.
Claims 2-4 recite a four plasmid packaging system which comprises “pGap/pol” in lines 7, 13, and 3, respectively. The term “pGap/pol” appears to be a typographic error. The term pGap/pol has been interpreted as intending to refer to “pGag/pol”. Appropriate correction is required.
Claim Rejections - 35 USC § 112
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, 3, and 12 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claims 1 and 12 recite the term “a sufficient amount” in lines 7 and 6 respectively, which is a subjective term which renders the claim indefinite. A claim may be rendered indefinite by reference to subjective term (see MPEP 2173.05(b), IV). The phrase “a sufficient amount” is not defined by the claim, the specification does not provide a standard for measuring the scope of the term, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
A claim that requires the exercise of subjective judgment without restriction may render the claim indefinite. In re Musgrave, 431 F.2d 882, 893, 167 USPQ 280, 289 (CCPA 1970). Claim scope cannot depend solely on the unrestrained, subjective opinion of a particular individual purported to be practicing the invention. Datamize LLC v. Plumtree Software, Inc., 417 F.3d 1342, 1350, 75 USPQ2d 1801, 1807 (Fed. Cir. 2005)); see also Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364, 1373, 112 USPQ2d 1188 (Fed. Cir. 2014) (holding the claim phrase "unobtrusive manner" indefinite because the specification did not "provide a reasonably clear and exclusive definition, leaving the facially subjective claim language without an objective boundary").
During prosecution, the applicant may overcome a rejection by amending the claim to remove the subjective term, or by providing evidence that the meaning of the term can be ascertained by one of ordinary skill in the art when reading the disclosure. However, "[f]or some facially subjective terms, the definiteness requirement is not satisfied by merely offering examples that satisfy the term within the specification." DDR Holdings, LLC v. Hotels.com, L.P., 773 F.3d 1245, 1261, 113 USPQ2d 1097, 1108 (Fed. Cir. 2014).
Claim 3 recites the term “serum-reduced medium” in lines 11 and 14 which is a relative term which renders the claim indefinite. The term “serum-reduced medium” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. As claimed, the scope of what constitutes a “serum-reduced” medium is not clear. Appropriate correction is required.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
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 1 is rejected under 35 U.S.C. 103 as being unpatentable over Oum et al. (2016, Click labeling of unnatural sugars metabolically incorporated into viral envelope glycoproteins enables visualization of single particle fusion. J. of Vir. Meth., 233, 62-71, here after “Oum”) in view of Cai et al (CN 109897881A, Espacenet translation attached, hereafter “Cai”).
With regard to claim 1, Oum teaches a method of non-invasive labeling of the membrane of virus glycoproteins via metabolic incorporation of unnatural sugars and subsequence click-reaction with fluorescent dyes and used to label HIV virus, which is considered to reasonably read on preparation of a fluorescently labeled lentiviral vector (Abstract). Oum teaches that, in order to produce fluorescently labeled lentivirus, 293T cells were transfected with a plasmid packaging system (Pg. 64, 2.2 Pseudovirus production) in culture medium supplemented with 50 µM N-azido-tetraacetyl mannosamine (Ac4ManNAz) in order to produced viruses comprising azide groups. Oum further teaches that the viruses comprising azide groups were harvested and used for click labeling of commercially available Alexa Fluor 488 DIBO and Alexa Fluor 647 DIBO fluorescent dyes (see Pg. 63, last para.) followed by removal of excess unreacted dye and collection of labeled virus (Pg. 66, right col., second para.). See also Fig. 1.
While Oum teaches use of labeling a virus comprising azide groups via clickable fluorescent dyes Alexa Fluor 488 and Alexa Fluor 647, Oum is silent as to use of DBCO-Cy5.
Cai teaches use of metabolic engineering (Para. [0011]) in a method of generating fluorescently labeled viruses via biorthogonal labeling which can be applied to both enveloped and non-enveloped viruses (Para. [0008]). Cai teaches that during host cell cultured, monosaccharide active groups are added, resulting in formation of modified host cells containing the monosaccharide active groups (Para. [0013]), virus are subsequently added to the modified host cells and cultured to obtain modified virus particles containing the active groups (Para. [0014], then modified viruses are incubated with fluorescent probes containing reactive groups to obtain fluorescently labeled viruses (Para. [0015]). Cai teaches that the active group can be an azide (Para. [0026]) and that the reactive group can be a DBCO (Para. [0027]) and further that the monosaccharide active group can be Ac4ManNAz (Para. [0029]) and that the fluorescent probe can be a commercially available Cy5 DBCO (Para. [0040]).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention, to choose DBCO-Cy5 as the fluorescent dye as taught by Cai for use in Oum’s method of generating a fluorescently labeled lentivirus with a reasonable expectation of success. A skilled artisan would have chosen DBCO-Cy5 as taught by Cai because far-red fluorescent dyes are well known in the art and are commonly used in order to reduce background autofluorescence or for applications which use multiple fluorescent probes. A skilled artisan would have had a reasonable expectation of success as both Oum and Cai teach use of metabolic labeling via introduction of modified monosaccharides into a host cell which are passed on to a virus for generating fluorescently labeled viruses and both teach viral labeling of commercially available fluorescent dyes via click chemistry.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Oum and Cai as applied to claim 1 above, and further in view of Pirona et al. (2020, Process for an efficient lentiviral cell transduction. Bio. Methods and Protocols, 5(1), bpaa005, hereafter “Pirona”).
With regard to claim 2, as detailed above, Oum in view of Cai suggest a method of non-invasive labeling of the membrane of HIV glycoproteins via metabolic incorporation of unnatural sugars and subsequence DBCO-Cy5 click-reaction.
The combination of Oum and Cai do not teach use of a three plasmid packaging system comprising the vector plasmid, and packaging plasmids PsPAX2 and PMD2.G.
Pirona teaches a process for lentiviral cell transduction comprising transfection of 293T cells with plasmids comprising a lentiviral sgRNA library, which is considered to reasonably read on a three plasmid packing system comprising a vector plasmid; psPAX2; and pMD2.G (Pg. 3, left col., 3rd para.).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention, to choose to use a three plasmid packaging system comprising a vector plasmid, psPAX2; and pMD2.G as taught by Pirona in the method of making fluorescently labeled lentiviral vectors as taught by the combination of Oum and Cai which a reasonably expectation of success. A skilled artisan would have been motivated to choose a plasmid packaging system comprising a vector plasmid, psPAX2; and pMD2.G because Pirona teaches that system is effective for producing lentiviral vectors for use in CRISPR-Cas systems via transduction in 293T cells (See Fig. 4). A skilled artisan would have had a reasonable expectation of success as both Oum and Pirona teach production of lentiviral vectors in 293T cells.
Claims 3-4, 12, and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Oum, Cai, and Pirona as applied to claims 1 and 2 above and further in view of Kuroda et al. (2009, Simplified lentivirus vector production in protein-free media using polyethylenimine-mediated transfection. J. of Vir. Methods, 157(2), 113-121, hereafter “Kuroda”).
With regard to claim 3, as detailed above, the combination of Oum, Cai, and Pirona teach production of Cy5 labeled lentiviral vectors via incorporation of an azido sugar into a 293T cell membrane and transfection using a three packaging plasmid system resulting in a viral vector comprising an azido sugar and subsequent incubation with a fluorescent dye.
Oum teaches that 293T cells are cultured in DMEM media comprising fetal bovine serum, which is considered to reasonably read on culturing in a cell medium (Pg. 64, left col., 1st para.), that medium contained an azido sugar (Pg. 66, right col., 2nd para.), and, further, that transfection media is removed and replaced with fresh growth medium prior to collection of viral containing supernatant (Pg. 64, right col.).
Pirona teaches a polyethyenimine (PEI) transfection protocol of subcultured cells where the vector plasmid, psPAX2, and pMD2.G are mixed in Opti-MEM medium, which is considered to reasonably read on a serum-reduced medium. This is considered to reasonably read on solution A as instantly claimed. Pirona also teaches that PEI is dissolved in Opti-MEM (i.e., serum-reduced medium) which is considered to reasonably read on solution B as instantly claimed. Further, Pirona teaches that solutions A and B, the “transfection solution” are mixed and then added dropwise to the 293T cells, which is considered to reasonably read on conducting transfection, after which fresh growth media containing fetal bovine serum is added and the supernatant containing viruses is collected and filtered (Pg. 3, left col., 3rd para.).
Therefore, as use of the method of Pirona comprising use of a three plasmid packaging system comprising a vector plasmid, psPAX2; and pMD2.G would have been obvious to one having ordinary skill in the art, the use of the specific method steps of Pirona regarding preparation of solutions A and B and addition of the transfection solution dropwise is also considered to be obvious to a skilled artisan. A skilled artisan would have been motivated to use the steps as taught by Pirona in the method as taught by the combination of Oum and Cai because Pirona teaches this method is successful for producing lentiviral vectors in 293T cells (See Fig. 4) and would have had a reasonable expectation of success as both Oum and Pirona teach production of lentiviral vectors in 293T cells.
Oum and Pirona are silent as to the use of serum free media during transfection of 293T cells.
Kuroda teaches an optimized protocol for lentiviral vector production using PEI transfection in 293T cells (Abstract). Kuroda teaches that 293T cells are cultured in DMEM comprising fetal bovine serum (Pg. 114, left col. 3rd full para.), DMEM without serum was used during transfection, fresh medium was replaced after transfection, and virus containing medium was collected and filtered (Pg. 114, right col., 1st para.). Kuroda teaches that use of DMEM without serum results in high viral titers and concludes that “the need for serum during lentiviral vector production can be bypassed” which results in significant cost savings and a simplified procedure due to reductions in cost and labor (Pg. 115, right col., 2nd & 3rd full paras.).
Therefore, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the instant invention, to apply replacement of the serum containing culture medium with serum-free medium prior to transfection as taught by Kuroda to the method of generating fluorescently labeled viral vectors as taught by the combination of Oum, Cai, and Pirona with a reasonable expectation of success. A skilled artisan would have been motivated to conduct transfection in serum free media as taught by Kuroda because Kuroda teaches that use of serum free media still results in high viral titers and reduces cost and labor, resulting in a simplified procedure. One having ordinary skill in the art would have had a reasonable expectation of success because Oum, Pirona, and Kuroda all teach production of lentiviral vectors in 293T cells.
With regard to claim 4, as detailed above, the combination of Oum, Cai, and Pirona teach production of Cy5 labeled lentiviral vectors via incorporation of an azido sugar into a 293T cell membrane and transfection using a three packaging plasmid system resulting in a viral vector comprising an azido sugar and subsequent incubation with a fluorescent dye. Pirona teaches that the three vector packaging system comprising vector plasmid, psPAX2, and PMD2.G are used at a ratio of 8:4:4 (i.e., 2:1:1) (Pg. 3, left col., 3rd para.).
Kuroda teaches lentiviral vector production using PEI transfection in 293T cells (Abstract) and that the ratio of vector, helper, and envelope plasmids are 3:2:1 (Pg. 114, left col. 3rd full para.).
Therefore, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the instant invention, to choose the ratio 3:2:1 ratio of vector, helper, and envelope plasmids as taught by Kuroda to the method of producing a fluorescently labeled lentiviral vector as taught by the combination of Oum, Cai, and Pirona with a reasonable expectation of success. A skilled artisan would have been motivated to choose the ratio as taught by Kuroda because Kuroda teaches that that ratio is effective for production of lentiviral vectors in 293T cells and because a skilled artisan would recognize that increasing the amount of vector plasmid would result in more vector plasmid being available for packaging and increasing the helper plasmid would improve packaging efficiency. One having ordinary skill in the art would have had a reasonable expectation of success as both Pirona and Kuroda teach transfection of 293T cells for production of lentiviral vectors and Kuroda teaches that a 3:2:1 ratio of vector, helper, and envelope plasmids is useful for transduction of lentiviral vectors in 293T cells.
Independently, MPEP 2144.05(II)(A) states
“Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Both Pirona and Kuroda teach ratios of vector, helper, and envelope plasmids which can be used for transfection to produce lentiviral vectors. A skilled artisan would have recognized that adjustment of the ratio of vector, transfer, and envelope plasmids could be adjusted in order to optimize the amount of virus produced in different types of cell in different culture conditions. Therefore, a skilled artisan could have arrived at the instantly claimed ratio via routine optimization, particularly since Kuroda teaches a 3:2:1 ratio is an effective ratio for transfection of lentiviral vectors in 293T cells.
With regard to claim 12, Oum, Cai, and Pirona teach production of Cy5 labeled lentiviral vectors via incorporation of an azido sugar into a 293T cell membrane and transfection using a three packaging plasmid system resulting in a viral vector comprising an azido sugar and subsequent incubation with a fluorescent dye. Oum teaches use of N-azido-tetraacetyl mannosamine (Ac4ManNAz). Oum is silent as to the specific temperature at which coincubation of 293 cells and azido sugar is performed and teaches that viruses comprising azido groups and the fluorescent dye were incubated at room temperature for 1 hour (Pg. 66, right col., second para.). However, 37°C is considered standard culture temperature for mammalian cell lines which would be well known to one having ordinary skill in the art and therefore, a skilled artisan would have been likely to conduct coincubation of 293T cells and azido sugar at 37°C. Similarly, a skilled artisan would recognize that increased temperature generally speeds up chemical reactions and therefore would have easily been able to envision incubating the virus comprising azide groups with the fluorescent dye at standard culture temperature of 37°C in order to speed up the click chemistry reaction.
With regard to claim 16, Oum teaches use of an azido sugar having a concentration of 50µM.
Conclusion
No claims are allowed.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIN V PAULUS whose telephone number is (571)272-6301. The examiner can normally be reached Mon-Fri 8 AM-5 PM.
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/ERIN V PAULUS/ Examiner, Art Unit 1631
/ARTHUR S LEONARD/ Examiner, Art Unit 1631
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