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 .
DETAILED ACTION
Acknowledgement is hereby made of receipt and entry of the communication filed on Feb. 27, 2026. Claims 1-2, 5-6, 8-9, 11, 13, 19-20, 25-26, 28, 39-42, 45-47 and 50-52 are pending and are currently examined.
Claim Objection
(Previous objection- withdrawn) The claims 1, 13 and 51-52 are objected to because of the following informalities:
Regarding claims 1 and 51-52, the “in” in the sentence “wherein the viral envelope glycoprotein in incorporated into the viral envelope of the isolated rVSV” should be “is”.
Regarding claim 13, it should recite “or” after part (e).
This objection is withdrawn in view of the amendment filed on Feb.27, 2026.
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.
(Previous rejection- withdrawn) Claims 1-2, 5-6, 8-9, 11, 13, 19-20, 25-26, 28, 39-42 ,45-47, 50-52 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as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.
This rejection is withdrawn in view of the amendment filed on Feb. 27, 2026.
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.
(Previous rejection- maintained) Claims 1-2, 5-6, 8-9, 11, 13, 20, 25-26, 28, 40-42, 45-47 and 50 are rejected under 35 U.S.C. 103 as being unpatentable over Torriani et al. (J Virol. 2019 Mar 5;93(6): e01744-18).
The base claim 1 is directed to a method of producing replication-incompetent recombinant vesicular stomatitis virus (rVSV) in suspension cell culture, comprising:
(a) inoculating, in a suspension cell culture medium with a plurality of packaging cells;
(b) transfecting the packaging cells in the suspension cell culture medium with a plasmid comprising a nucleic acid molecule encoding a viral envelope glycoprotein to produce a population of packaging cells expressing the viral envelope glycoprotein;
(c) introducing rVSV into the suspension cell culture medium at a multiplicity of infection (MOI) rate of from 0.001 to 3 to infect the population of packaging cells expressing the viral envelope glycoprotein, wherein the rVSV has been engineered to delete the glycoprotein; and
(d) isolating rVSV produced from the population of packaging cells from 15 to 65 hours post infection, wherein the viral envelope glycoprotein in incorporated into the viral envelope of the isolated rVSV.
Torriani et al. describes the identification of Clotrimazole Derivatives as Specific Inhibitors of Arenavirus Fusion and teaches that the clotrimazole-derivative TRAM-34 inhibits infection with VSV-based pseudotyped viruses containing the envelope glycoproteins of various arenaviruses, where the pseudotype viruses can overcome the strict biosafety requirements that limit work with these pathogens to BSL4 facilities (See page 3, paragraph 3). Torriani et al. teaches a method of producing a pseudotyped rVSV virus as claimed that comprising (a) growing 293 F (suspension cell, packing cell line) in a in 10-cm dishes (See e.g., page 14, paragraph 4); (b) a plasmid comprising a nucleic acid molecule encoding a viral envelope glycoproteins of interest such as from a member of the Arenaviridae family e.g. pCLCMV GP (LCMV clone-13), pC-LASV GPC strain Josiah and other strain of emerging viruses (See Page 14, paragraph 2 and Fig. 1, page 4 and below). These plasmids are transfected in the 293F cells using Lipofectamine (See e.g., page 14, paragraph 4); (c) The transfected 293F cells are then infected with rVSVΔG virus where the glycoprotein gene (G) was deleted at MOI 3-5 (See page 3, paragraph 3; See e.g., page 14, paragraph 4 and Fig. 1, page 4 and below); (d) After 24 h, the VSV pseudoparticles were collected that specifically yielded VSVΔGlucGFP pseudotypes decorated with the
PNG
media_image1.png
810
914
media_image1.png
Greyscale
heterologous GP of interest (GPint) (See page 4, Fig. 1 and below).
Accordingly, Torriani et al. teaches a method for producing a rVSV pseudo particles expressing envelope glycoprotein of interest in a suspension cells 293F. Although Torriani et al. does not use the term “replication-incompetent” as claimed, the rVSVΔG with the glycoprotein gene (G) deletion of Torriani et al. teaches the replication-incompetent rVSV, also, pseudoviruses are recombinant, replication-incompetent, viral particles designed to mimic the surface characteristics of native enveloped viruses (https://www.tandfonline.com/doi/full/10.1080/14760584.2023.2299380). As for the term “incorporated”, Torriani et al. teaches that the “VSVΔGlucGFP pseudotypes decorated with the heterologous GP of interest” indicates that the viral envelope glycoprotein in incorporated into the viral envelope of the isolated rVSV (See Fig. 1 Above).
Regarding claims 2, 5, 6 and 8, they require a specific MOI.
Torriani et al. teaches a viral infection MOI is 3 to 5 for 2 h at 37°C or MOI is 1 for 1.5 h at 37°C (See page 14), which may not teach exact the same MOI as claimed. However, it is a common knowledge that the MOI depends on the cell type, virus type, cell passage, and application of the experiment. According to section 2144.05 of the MPEP, 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). See also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 (“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.”). Because MOI is for the number of virions that are added per cell during infection, one of ordinary skill in the art would be able to test for an optimal MOI as claimed through routine experimentation. Therefore, the claimed MOI range would have been obvious unless there is evidence showing that they produce unexpected results.
Regarding claims 9 and 11, the time for harvesting a virus post-infection depends on the specific virus and its replication speed, the type of host cell and its susceptibility, the initial amount of virus (inoculum), and the specific experiment or goal, and one of ordinary skills would be able to test for an optimal time for harvesting virus as claimed through routine experimentation. Therefore, the claimed viral isolation hours post-infection would have been obvious unless there is evidence showing that they produce unexpected results.
Regarding claim 13, Torriani et al. teaches that the cells are Human lung alveolar epithelial cells A549, HeLa cells, HEK 293T, HEK 293F, and VeroE6 cells (See page 14, paragraph 3).
Regarding claim 20. Torriani et al. teaches rVSV pseudoparticles were produced with high efficiency, yielding robust specific titers (105 to 108 PFU/ml) (See page 4).
Regarding claims 25 and 26, Torriani et al. teaches they obtained pseudoparticles with high efficiency with robust titers from 10^5 to 10^8 IFU/ml and low unspecific background in 293F cells (See page 14, paragraph 4). It is obvious that one of skill in the art can compare the titer between the suspension cells and adherent based on the needs. Also, comparing the viral titer between the suspension and adherent cell lines are dependent on the specific virus, cell line and application goals, and is a routine experiment. One of ordinary skills would be able to test a method to increase the viral titer in both suspension and adherent cell lines and reach to a claimed titer through routine experimentation, and then compare them based on a specific condition and some desired requirements. Therefore, the claimed infectious titer comparison between suspension cells and adherent cells would have been obvious unless there is evidence showing that they produce unexpected results.
Claim 28, Torriani et al. teaches the glycoprotein of GP2 of arenaviruses is class I fusion proteins.
Regarding claim 40, Torriani et al. teaches that the 293F transfection is performed with Lipofectamine (See page 14, paragraph 4).
Regarding claims 41 and 42, Torriani et al. teaches the 293F packaging cell line is plated at 6 X 10^6 cells/dish and does not disclose the detailed amount on the ratio of the Lipofectamine and DNA concentration. However, it is a common knowledge in the art that each transfect agent will come with a suggested protocol on cell density and the transfection ratio such as Lipofectamine 2000 (https://www.thermofisher.com/us/en/home/references/protocols/cell-culture/transfection-protocol/lipofectamine-2000.html#:~:text=Prepare%20complexes%20using%20a%20DNA,6%20hours%20at%20room%20temperature), is suggested to use a DNA (μg) to Lipofectamine 2000 (μl) ratio of 1:2 to 1:3 for most cell lines. Therefore, the required amount of cell density and transfection reagent dosage can be achieved through routine experimentation optimization. Therefore, these claims would have been obvious unless there is evidence showing that they produce unexpected results.
Regarding claims 45-47, they require the specific transfection temperature. Torriani et al. teaches the Pseudotyped virus production is at 37°C (See page 14, paragraph 4), which is specific to the 293 cell they used with a specific condition. Based on the section 2144.05 of the MPEP described above, one of ordinary skills would be able to test for an optimal temperature as claimed through routine experimentation. Therefore, the claimed temperature would have been obvious unless there is evidence showing that they produce unexpected result.
Regarding claim 50, Torriani et al. teaches that “Briefly, HEK 293F cells were plated in 10-cm dishes at 6 x10^6 cells/dish and transiently transfected with plasmids encoding glycoproteins of interest using Lipofectamine. After 42 h cells were infected with rVSVΔG pseudotypes bearing VSVG using an MOI of 3 to 5 for 2 h at 37°C. Cells were subsequently washed twice with serum-free DMEM and incubated with fresh DMEM containing 10% fetal calf serum (FCS) (See page 14, paragraph 4), which does not indicate medium changes.
(Previous rejection- maintained) Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Torriani et al. (J Virol. 2019 Mar 5;93(6):e01744-18) as applied to claims 1-2, 5-6, 8-9, 11, 13, 20, 25-26, 28, 40-42, 45-47 and 50 above and in view of Sahni-SAFC-2012 (https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/870/145/r022.pdf?srsltid=AfmBOopa9AFdcyA8MiKMWwrCJEnsL3Kv6QHD31RmG9Mxy_89Bj2AKfhM).
Claim 19 requires the suspension cell culture medium is a serum-free and protein-free medium.
Torriani et al. teaches 293F cell using a serum-free DMEM medium. However, it does not teach a protein-free medium.
Sahni et al. teaches an EX-CELL 293 medium, which is a serum-free, animal-protein free medium specifically formulated to support large-scale, high-density suspension culture and virus production in the HEK 293 cell line (See page 1, left column). EX-CELL 293 medium produced high-density, highly viable HEK 293 cultures with up to 5 x 10^6 viable cells/mL, and supports highly viable HEK 293 cultures with most cultures above 98% viability. For example, HEK 293 cells grown in EX-CELL 293 medium produce high yields of adenovirus, up to 3 x 10^10 TCID50/mL.
It would have been prima facie obvious for one having ordinary skill in the art before the effective filing date of the claimed invention to introduce the medium of EX-CELL 293 into Torriani’s study to increase the yields of the rVSV production. Based on the advantage of the serum-free, animal-protein free medium taught by Sahni, one of skill in the art would have been motivated to do so to replace the DMEM with the EX-CELL 293 medium for increasing rVSV production, and there would be a reasonable expectation of success to develop an invention as claimed.
(Previous rejection- maintained) Claim 39 is rejected under 35 U.S.C. 103 as being unpatentable over Torriani et al. (J Virol. 2019 Mar 5;93(6):e01744-18) as applied to claims 1-2, 5-6, 8-9, 11, 13, 20, 25-26, 28, 40-42, 45-47 and 50 above and in view of Dieterle et al. (Cell Host Microbe. 2020 Sep 9;28(3):486-496.e6. Epub 2020 Jul 3) as evidenced by ABP Biosciences ((https://www.abpbio.com/wp-content/uploads/2023/09/P017.pdf, downloaded on Nov. 20, 2025).
Claim 39 requires the packaging cells comprises use of a polyethylenimine transfection reagent.
Based on the description above, Torriani et al. teaches a method for transfecting the 293F cell with a plasmid comprising a nucleic acid molecule encoding a viral envelope glycoprotein by Lipofectamine, but it is silent on the polyethylenimine transfection reagent.
Dieterle et al. teaches a method for generating a rVSV encoding SARS-CoV-2 S and identify key passage-acquired mutations in the S glycoprotein that facilitate robust rVSV replication (See page 487, left column). During their study, Dieterle et al. teaches using polyethylenimine as a transfection reagent to generate the rVSV-SARS-CoV-2 and express SARS-CoV2 Spike Glycoprotein RBD in the suspension cell line, FreeStyle 293F cells (suspension) and 293FT cell (a variant of the HEK293 cell line that is primarily adherent but can be cultured in suspension: https://documents.thermofisher.com/TFS-Assets/LSG/manuals/Growth_and_Maintenance_of_293FT_Cell_Line_UG.pdf). Although Dieterle et al. does not discuss the transfection reagent polyethylenimine in details, the teachings of ABP discloses the advantages for using polyethylenimine as a transfection reagent in suspension cell line. ABP Biosciences teaches that the transfection grade polyethylenimine (PEI) is a powerful, trusted, and cost-effective reagent widely considered as a current gold standard for both in vitro and in vivo transfection. Stable complexation with DNA, efficient entry into the cell, and ability to escape the endosome makes PEI a highly efficient transfection reagent which is compatible for a wide range of cell lines/types including the most commonly used HEK293 and CHO cells grown in adherent and suspension cultures (See page 1).
It would have been prima facie obvious for one having ordinary skill in the art before the effective filing date of the claimed invention to introduce the PEI into Torriani’s study to arrive at an invention as claimed. Based on the advantage of PEI taught by ABP Biosciences, one of skill in the art would have been motivated to do so to replace Lipofectamine with the PEI for its cost-effectiveness and stability, and there would be a reasonable expectation of success to develop such an invention as claimed.
(Previous rejection- maintained) Claims 51-52 are rejected under 35 U.S.C. 103 as being unpatentable over Torriani et al. (J Virol. 2019 Mar 5;93(6):e01744-18) and in view of Dieterle et al. (Cell Host Microbe. 2020 Sep 9;28(3):486-496.e6. Epub 2020 Jul 3) as evidenced by ABP Biosciences ((https://www.abpbio.com/wp-content/uploads/2023/09/P017.pdf, downloaded on Nov. 20, 2025), and Kiesslich2020 (J Biotechnol. 2020 Feb 20; 310:32-39).
Claims 51 and 52 are directed to a method of producing replication-incompetent recombinant vesicular stomatitis virus (rVSV) comprising a suspension cell HEK293 with a transfection reagent polyethylenimine. The differences between claims 51 and 52 are the MOI numbers (MOI in claim 51 is about 0.01 and MOI in claim 52 is about 1) and the rVSV isolation time post-infection (the hours in claim 51 is 40-48 and the hours in claim 52 is 20-28).
Based on the descriptions of Torriani et al. above, Torriani et al. teaches claim 51-52 at (a) culture the suspension 293F cell at a temperature of about 37°C.
For (b), Torriani et al. teaches a method for transfecting the 293F cell with a plasmid comprising a nucleic acid molecule encoding a viral envelope glycoprotein by Lipofectamine (See page 14), but does not teach the polyethylenimine (PEI) transfection reagent.
Based on the description above in claim 39, Dieterle et al. teaches using polyethylenimine as a transfection reagent to generate the rVSV-SARS-CoV-2 and express SARS-CoV2 Spike Glycoprotein RBD in the suspension cell line, FreeStyle 293F cells (suspension) and 293FT cell (a variant of the HEK293 cell line that is primarily adherent but can be cultured in suspension: https://documents.thermofisher.com/TFS-Assets/LSG/manuals/Growth_and_Maintenance_of_293FT_Cell_Line_UG.pdf). Although Dieterle et al. does not discuss the transfection reagent polyethylenimine in details, the teachings of ABP discloses the advantages for using polyethylenimine as a transfection reagent in suspension cell line as described above.
For (C), Torriani et al. teaches infection/introducing the rVSV with glycoprotein deletion into 293F cell at 37°C and not 34 °C. Kiesslich2020 teaches that HEK 293 SF (suspension) cell can produce higher titer of rVSV viral particles at “…cells continued to grow for the first 24 hpi despite a temperature shift to 34 °C. Moreover, the cell specific yield was only 11.2 TCID50/cell in Vero compared to 10^3 in HEK 293SF. Similarly, the genomic titer fell short with 7.90×10^8 VG/mL in Vero at 24 hpi, compared to 5.95×10^9 VG/mL in HEK 293SF at 36 hpi, at their respective peak of infectious titer (See page 37, right column, paragraph 3). In addition, based on the section 2144.05 of the MPEP described above, one of ordinary skills would be able to test for an optimal temperature for viral particle productions as claimed through routine experimentation. Therefore, the claimed temperature would have been obvious unless there is evidence showing that they produce unexpected result.
It would have been prima facie obvious for one having ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings from Torriani, Dieterle, ABP Biosciences and Keisslich2020 to arrive at an invention as claimed. Based on the advantages ABP Biosciences taught for using the suspension HEK293 cells with the polyethylenimine transfection reagent, one of skill in the art would have been motivated to do so to introduce the PEI into Torriani’s study, and there would be a reasonable expectation of success to develop such a method for producing a rVSV as claimed, especially, Dieterle already teaches a method to apply the suspension HEK293 cells with PEI for generating the rVSV particles.
As for the MOI, according to section 2144.05 of the MPEP described above, because MOI is for the number of virions that are added per cell during infection, one of ordinary skills would be able to test for an optimal MOI as claimed through routine experimentation. Therefore, the claimed MOI range would have been obvious unless there is evidence showing that they produce unexpected results.
As for the rVSV collecting time post-infection, it is a common knowledge in the art that the optimal time to harvest viruses after infection is highly dependent on the specific virus type, the host cell line, the multiplicity of infection (MOI), and other conditions like temperature and medium type. For example, Torriani et al. teaches harvest rVSV at 24hour and ABP Bioscience teaches that the rAAVs can gelibe harvested at 48-96 hours post-transfection in suspension 293 cells with PEI (See page 9). Therefore, one of ordinary skills would be able to test for an optimal isolation time as claimed through routine experimentation. Therefore, the claimed isolation time would have been obvious unless there is evidence showing that they produce unexpected results.
Responses to Applicant’s Remarks
Applicant’s arguments filed on Feb. 27, 2026 has been received and fully considered.
1). Applicant’s amendment on claim objection is considered and the objection is withdrawn.
2). Applicant’s amendment and argument on rejections under 35 U.S.C. § 112 (b) is considered and the rejection is withdrawn.
3). Applicant’s arguments on rejection under 35 U.S.C. § 103 is not found persuasive as follows:
(i) Applicant argued that Torriani does not discuss production of pseudotype virus in suspension cell culture by allegedly stating that Torriani discusses a conventional anchorage-dependent cell cultivation technique, referring to plating HEK 293F cells in 10-cm dishes for transfection with plasmids (See Remarks, page 11).
The argument is not persuasive.
The HEK 293F Torriani used for producing the rVSV (See Torriani, page 14) is a well-known suspension cell line. This can be demonstrated by iCytion (https://www.cytion.com/HEK293-F-Cells/300260). Cytion teaches that HEK293-F cells are a fast-growing, highly transfectable subline derived from the human embryonic kidney 293 (HEK293) cell line. The 'F' designation indicates that these cells have been adapted for growth in suspension cultures, making them particularly useful for large-scale protein production (See page 2). The above description is also a response to applicant’s argument on claims 19, 39, 51 and 52 regarding the suspension cell culture of the HEK293F (See Remarks, page 11, paragraph 2).
(ii) Applicant also argued that Sahni, Dieterle, ABP or Kiesslich provide no guidance to alter the conclusions as allegedly argued that Torriani is insufficient to support the HEK 293F is a suspension cell culture (See Remarks, page 11).
The argument is not persuasive.
Torriani teaches producing rVSV particles using a suspension cell line that is sufficient. Each of the references of Sahni, Dieterle, ABP or Kiesslich is used to support rejecting a specific limitation as claimed. It is applicable to use Torriani in view of these art references in the office action.
Conclusion
No claims are allowed.
THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 extension fee 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 date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RUIXUE WANG whose telephone number is (571)272-7960. The examiner can normally be reached Monday-Friday 8:00 am-5:00 pm, 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.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Thomas J. Visone can be reached on (571) 270-0684. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/RUIXUE WANG/ Examiner, Art Unit 1672
/NICOLE KINSEY WHITE/ Primary Examiner, Art Unit 1672
i Cytion is cited solely to respond to applicant’s argument and not to reject any claim.
Prosecution Insights