Shanghai Zerun Biotech Co.
Shanghai Zerun Biotech Co.
Wang D.,Merck And Co. |
Phan S.,University of Georgia |
DiStefano D.J.,Merck And Co. |
Citron M.P.,Merck And Co. |
And 9 more authors.
Journal of Virology | Year: 2017
Human respiratory syncytial virus (RSV) is a common cause of severe respiratory disease among infants, immunocompromised individuals, and the elderly. No licensed vaccine is currently available. In this study, we evaluated two parainfluenza virus 5 (PIV5)-vectored vaccines expressing RSV F (PIV5/F) or G (PIV5/G) protein in the cotton rat and African green monkey models for their replication, immunogenicity, and efficacy of protection against RSV challenge. Following a single intranasal inoculation, both animal species shed the vaccine viruses for a limited time but without noticeable clinical symptoms. In cotton rats, the vaccines elicited RSV F- or G-specific serum antibodies and conferred complete lung protection against RSV challenge at doses as low as 103 PFU. Neither vaccine produced the enhanced lung pathology observed in animals immunized with formalin-inactivated RSV. In African green monkeys, vaccine-induced serum and mucosal antibody responses were readily detected, as well. PIV5/F provided nearly complete protection against RSV infection in the upper and lower respiratory tract at a dose of 106 PFU of vaccine. At the same dose levels, PIV5/G was less efficacious. Both PIV5/F and PIV5/G were also able to boost neutralization titers in RSV-preexposed African green monkeys. Overall, our data indicated that PIV5/F is a promising RSV vaccine candidate. © 2017 American Society for Microbiology. All Rights Reserved.
Xu D.-J.,Walvax Biotechnology |
Ma B.,Walvax Biotechnology |
Qian W.,Walvax Biotechnology |
Zeng X.-F.,Shanghai Zerun Biotech Co.
Chinese Journal of Pharmaceutical Biotechnology | Year: 2015
Using improved low-salt medium, the recombinant HPV18L1 late protein was expressed by Pichia pastorius at 30 L Sartorious bioreactor (C30-3). Various parameters affecting expression of HPV18L1 protein in accumulation and induction phases, such as medium components, pH value, temperature, stirring speed, dissolved oxygen, addition of glycerol and methanol, were evaluated. The results showed that the optimized low-salt medium is more suitable for the growth of the yeast Pichia cells. During accumulation stage, pH of the culture medium 5.0, temperature 31℃, DO content of 20% to 25% and stirring speed 500 r/min were maintained, 3 000 mL of 40% glycerol solution was added at a constant feed rate for the first 20 h until the Pichia wet weight ≥190 mg/mL and then feeding of glycerol was stopped and Pichia was cultivated for additional 4 h to exhaust glycerol. After entering the recombinant Pichia expression HPV18L1 protein induced late stage, to maintain the culture pH5.2, temperature 29℃, DO content of 45%, stirring speed 600 r/min, methanol concentration control culture medium supplemented with 4% methanol online and induction 60 h. Late HPV18L1 protein expression reached 311.43 mg/L. 30 L Stable expression of recombinant HPV18L1 protein by Pichia at 30 L Sartorious bioreactor (C30-3) was established. © 2015, Editorial Board of Pharmaceutical Biotechnology. All right reserved.
Shen Q.,Shanghai Zerun Biotech Co. |
Lei J.-Q.,Shanghai Zerun Biotech Co. |
Zhou C.-M.,Shanghai Zerun Biotech Co. |
Zhang G.-X.,Shanghai Zerun Biotech Co.
Chinese Journal of Biologicals | Year: 2012
Objective: To express human papillomavirus (HPV) 18 L1 protein in Pichia pastoris, purify the virus-like particles (VLPs) and determine its immunogenicity. Methods: Recombinant plasmid pHPV18 L1 was transformed to P. pastoris X-33 by electrotransformation and induced with methanol. The expressed recombinant HPV18 L1 protein was identified by SDS-PAGE and Western blot, then purified by ion exchange chromatography and molecular sieve chromatography, and analyzed for purity by SEC-HPLC, for particle size distribution and structure by dynamic light scattering and transmission electron microscopy, and for immunogenicity by determination of ED 50 in mice and antibody titer in rats. Results: HPV18 L1 protein, with a relative molecular mass of about 55 000, was effectively expressed in P. pastoris, which showed specific binding to mouse anti-HPV18 L1 monoclonal antibody. The purified HPV18 L1 protein reached a purity of 99%, of which the VLPs were even in size, at a diameter of about 50 nm. The HPV18 L1 protein after adsorption with aluminum hydroxide induced high antibody titer in rats, of which the ED 50 in mice was 0.006 68 μg. Conclusion: Self-assembled HPV18 L1 was highly expressed in P. pastoris, of which the VLPs showed high immunogenicity after purification and adsorption with aluminum hydroxide. It laid a foundation of industrial production of HPV18 L1 vaccine.
Mallajosyula V.V.,Indian Institute of Science |
Citron M.,Merck And Co. |
Ferrara F.,University of Kent |
Temperton N.J.,University of Kent |
And 4 more authors.
Frontiers in Immunology | Year: 2015
Seasonal epidemics caused by influenza A (H1 and H3 subtypes) and B viruses are a major global health threat. The traditional, trivalent influenza vaccines have limited efficacy because of rapid antigenic evolution of the circulating viruses. This antigenic variability mediates viral escape from the host immune responses, necessitating annual vaccine updates. Influenza vaccines elicit a protective antibody response, primarily targeting the viral surface glycoprotein hemagglutinin (HA). However, the predominant humoral response is against the hypervariable head domain of HA, thereby restricting the breadth of protection. In contrast, the conserved, subdominant stem domain of HA is a potential "universal" vaccine candidate. We designed an HA stem-fragment immunogen from the 1968 pandemic H3N2 strain (A/Hong Kong/1/68) guided by a comprehensive H3 HA sequence conservation analysis. The biophysical properties of the designed immunogen were further improved by C-terminal fusion of a trimerization motif, "isoleucine-zipper", or "foldon". These immunogens elicited cross-reactive, antiviral antibodies and conferred partial protection against a lethal, homologous HK68 virus challenge in vivo. Furthermore, bacterial expression of these immunogens is economical and facilitates rapid scale-up. © 2015 Mallajosyula, Citron, Ferrara, Temperton, Liang, Flynn and Varadarajan.