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  1. Article ; Online: Comprehensive Flow Cytometry Analysis of PEI-Based Transfections for Virus-Like Particle Production

    Daniel J. Blackstock / Alvenne Goh / Shamitha Shetty / Giulia Fabozzi / Rong Yang / Vera B. Ivleva / Richard Schwartz / Joseph Horwitz

    Research, Vol

    2020  Volume 2020

    Abstract: The generation of stable clones for biomolecule production is a common but lengthy and labor-intensive process. For complex molecules, such as viruses or virus-like particles (VLPs), the timeline becomes even more cumbersome. Thus, in the early stages of ...

    Abstract The generation of stable clones for biomolecule production is a common but lengthy and labor-intensive process. For complex molecules, such as viruses or virus-like particles (VLPs), the timeline becomes even more cumbersome. Thus, in the early stages of development, transient production methods serve as a reasonable alternative to stable clone construction. In this work, an investigation of a polyethylenimine- (PEI-) based transfection method for the transient production of Chikungunya (Chik) VLPs, a vaccine candidate molecule, was undertaken. This effort focuses on tracking cell population responses during transfection, understanding how process changes affect these responses, and monitoring patterns in cell performance over the culture duration. Plasmid labeling and VLP staining were employed to comprehensively track cells via flow cytometry and to draw correlations between plasmid DNA (pDNA) uptake and the resulting VLP expression. The method detected high transfection efficiency (≥97%) in all samples tested and demonstrated the capability to track kinetics of plasmid-cell binding. With varied transfection cell concentrations, the pDNA binding kinetics are altered and saturation binding is observed in the lowest cell concentration sample tested in less than 3 hours of incubation. Interestingly, in all samples, the flow cytometry analysis of relative pDNA amount versus VLP expression staining showed that cells which contained fewer pDNA complexes resulted in the highest levels of VLP stain. Finally, to determine the potential breadth of our observations, we compared daily expression patterns of ChikVLP with a reporter, monomeric GFP molecule. The similarities detected suggest the interpretations presented here to likely be more broadly informative and applicable to PEI-based transient production of additional biological products as well.
    Keywords Science ; Q
    Subject code 500
    Language English
    Publishing date 2020-01-01T00:00:00Z
    Publisher American Association for the Advancement of Science
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Engineering of HIV-1 neutralizing antibody CAP256V2LS for manufacturability and improved half life

    Baoshan Zhang / Deepika Gollapudi / Jason Gorman / Sijy O’Dell / Leland F. Damron / Krisha McKee / Mangaiarkarasi Asokan / Eun Sung Yang / Amarendra Pegu / Bob C. Lin / Cara W. Chao / Xuejun Chen / Lucio Gama / Vera B. Ivleva / William H. Law / Cuiping Liu / Mark K. Louder / Stephen D. Schmidt / Chen-Hsiang Shen /
    Wei Shi / Judith A. Stein / Michael S. Seaman / Adrian B. McDermott / Kevin Carlton / John R. Mascola / Peter D. Kwong / Q. Paula Lei / Nicole A. Doria-Rose

    Scientific Reports, Vol 12, Iss 1, Pp 1-

    2022  Volume 11

    Abstract: Abstract The broadly neutralizing antibody (bNAb) CAP256-VRC26.25 has exceptional potency against HIV-1 and has been considered for clinical use. During the characterization and production of this bNAb, we observed several unusual features. First, the ... ...

    Abstract Abstract The broadly neutralizing antibody (bNAb) CAP256-VRC26.25 has exceptional potency against HIV-1 and has been considered for clinical use. During the characterization and production of this bNAb, we observed several unusual features. First, the antibody appeared to adhere to pipette tips, requiring tips to be changed during serial dilution to accurately measure potency. Second, during production scale-up, proteolytic cleavage was discovered to target an extended heavy chain loop, which was attributed to a protease in spent medium from 2-week culture. To enable large scale production, we altered the site of cleavage via a single amino acid change, K100mA. The resultant antibody retained potency and breadth while avoiding protease cleavage. We also added the half-life extending mutation LS, which improved the in vivo persistence in animal models, but did not impact neutralization activity; we observed the same preservation of neutralization for bNAbs VRC01, N6, and PGDM1400 with LS on a 208-virus panel. The final engineered antibody, CAP256V2LS, retained the extraordinary neutralization potency of the parental antibody, had a favorable pharmacokinetic profile in animal models, and was negative in in vitro assessment of autoreactivity. CAP256V2LS has the requisite potency, developability and suitability for scale-up, allowing its advancement as a clinical candidate.
    Keywords Medicine ; R ; Science ; Q
    Language English
    Publishing date 2022-10-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Tyrosine O-sulfation proteoforms affect HIV-1 monoclonal antibody potency

    Cindy X. Cai / Nicole A. Doria-Rose / Nicole A. Schneck / Vera B. Ivleva / Brad Tippett / William R. Shadrick / Sarah O’Connell / Jonathan W. Cooper / Zachary Schneiderman / Baoshan Zhang / Daniel B. Gowetski / Daniel Blackstock / Jacob Demirji / Bob C. Lin / Jason Gorman / Tracy Liu / Yile Li / Adrian B. McDermott / Peter D. Kwong /
    Kevin Carlton / Jason G. Gall / Q. Paula Lei

    Scientific Reports, Vol 12, Iss 1, Pp 1-

    2022  Volume 11

    Abstract: Abstract CAP256V2LS, a broadly neutralizing monoclonal antibody (bNAb), is being pursued as a promising drug for HIV-1 prevention. The total level of tyrosine-O-sulfation, a post-translational modification, was known to play a key role for antibody ... ...

    Abstract Abstract CAP256V2LS, a broadly neutralizing monoclonal antibody (bNAb), is being pursued as a promising drug for HIV-1 prevention. The total level of tyrosine-O-sulfation, a post-translational modification, was known to play a key role for antibody biological activity. More importantly, here wedescribe for the first time the significance of the tyrosine-O-sulfation proteoforms. We developed a hydrophobic interaction chromatography (HIC) method to separate and quantify different sulfation proteoforms, which led to the direct functionality assessment of tyrosine-sulfated species. The fully sulfated (4-SO3) proteoform demonstrated the highest in vitro relative antigen binding potency and neutralization efficiency against a panel of HIV-1 viruses. Interestingly, highly variable levels of 4-SO3 were produced by different clonal CHO cell lines, which helped the bNAb process development towards production of a highly potent CAP256V2LS clinical product with high 4-SO3 proteoform. This study presents powerful insight for any biotherapeutic protein development where sulfation may play an important role in product efficacy.
    Keywords Medicine ; R ; Science ; Q
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Soluble prefusion-closed HIV-envelope trimers with glycan-covered bases

    Adam S. Olia / Cheng Cheng / Tongqing Zhou / Andrea Biju / Darcy R. Harris / Anita Changela / Hongying Duan / Vera B. Ivleva / Wing-Pui Kong / Li Ou / Reda Rawi / Yaroslav Tsybovsky / David J. Van Wazer / Angela R. Corrigan / Christopher A. Gonelli / Myungjin Lee / Krisha McKee / Sandeep Narpala / Sijy O’Dell /
    Danealle K. Parchment / Erik-Stephane D. Stancofski / Tyler Stephens / Ivy Tan / I-Ting Teng / Shuishu Wang / Qing Wei / Yongping Yang / Zhengrong Yang / Baoshan Zhang / Jan Novak / Matthew B. Renfrow / Nicole A. Doria-Rose / Richard A. Koup / Adrian B. McDermott / Jason G. Gall / Q. Paula Lei / John R. Mascola / Peter D. Kwong

    iScience, Vol 26, Iss 8, Pp 107403- (2023)

    2023  

    Abstract: Summary: Soluble HIV-1-envelope (Env) trimers elicit immune responses that target their solvent-exposed protein bases, the result of removing these trimers from their native membrane-bound context. To assess whether glycosylation could limit these base ... ...

    Abstract Summary: Soluble HIV-1-envelope (Env) trimers elicit immune responses that target their solvent-exposed protein bases, the result of removing these trimers from their native membrane-bound context. To assess whether glycosylation could limit these base responses, we introduced sequons encoding potential N-linked glycosylation sites (PNGSs) into base-proximal regions. Expression and antigenic analyses indicated trimers bearing six-introduced PNGSs to have reduced base recognition. Cryo-EM analysis revealed trimers with introduced PNGSs to be prone to disassembly and introduced PNGS to be disordered. Protein-base and glycan-base trimers induced reciprocally symmetric ELISA responses, in which only a small fraction of the antibody response to glycan-base trimers recognized protein-base trimers and vice versa. EM polyclonal epitope mapping revealed glycan-base trimers –even those that were stable biochemically– to elicit antibodies that recognized disassembled trimers. Introduced glycans can thus mask the protein base but their introduction may yield neo-epitopes that dominate the immune response.
    Keywords Molecular structure ; Virology ; Science ; Q
    Subject code 500
    Language English
    Publishing date 2023-08-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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