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Sun L.,Chinese National Institute for Viral Disease Control and Prevention | Chen Z.,Chinese National Institute for Viral Disease Control and Prevention | Yu L.,Chinese National Institute for Viral Disease Control and Prevention | Wei J.,North China Pharmaceutical Corporation | And 7 more authors.
Applied Microbiology and Biotechnology | Year: 2012

The currently recommended treatment for individuals exposed to rabies virus (RV) is post-exposure prophylaxis (PEP) through the combined administration of rabies vaccine and rabies immune globulin (RIG). Human monoclonal antibodies (mAbs) that neutralize RV offer an opportunity to replace RIG for rabies PEP. Here, a combinatorial human Fab library was constructed using antibody genes derived from the blood of RV-vaccinated donors. Selections of this library against purified RV virions resulted in the identification of 11 unique Fab antibodies specific for RV glycoprotein. Of the Fab antibodies, five were converted to full human IgG1 format. The human IgG antibodies revealed high binding affinity and neutralizing activities against RV fixed strains through a rapid fluorescent focus inhibition test in vitro as well as the early stage protective function after exposure to RV infection in vivo. Furthermore, epitope mapping and binding competition analysis showed that all of obtained human neutralizing and protective antibodies were directed to the antigenic site II of RV glycoprotein. Our results provide not only important insight into the protective immune response to RV in humans, but also more candidates eligible for use in a mAb cocktail aimed at replacing RIG for rabies post-exposure prophylaxis. © Springer-Verlag 2012. Source

Cheng L.-J.,North China Pharmaceutical Corporation
Chinese Journal of Biologicals | Year: 2011

Objective: To verify the process for virus removal from recombinant monoclonal antibody product by affinity chromatography. Methods: The efficacies of virus removal from recombinant monoclonal antibody against rabies virus by novel and traditional rProtein A Sepharose Fast Flow (rProtein A SFF) chromatography were evaluated using influenza virus subtype H1N1, herpes simplex virus type 1 and adenovirus type 5 as model viruses. Results: All the titers of three kinds of model viruses decreased by more than 4. 0 log 10 after purification by novel and traditional rProtein A SFF chromatography. Conclusion: The rProtein A SFF affinity chromatography is effective in removal of potential virus contamination from recombinant monoclonal antibody products. Source

Wang H.,North China Pharmaceutical Corporation | Wei J.-S.,North China Pharmaceutical Corporation
Chinese Journal of Biologicals | Year: 2015

An IgG molecule is composed of two heavy and two light chains covalently linked by interchain disulfide bonds. Each domain of the heavy or light chain contains one additional disulfide bond. However, there is unpaired non-canonical cysteine in a handful of natural immunoglobulin and recombinant antibody molecules. This paper reviews the unpaired non-canonical cysteine in IgG and its influence on cell expression and molecular stability, characterization of its cysteinylation and the means of de-cysteinylation. Source

Chen H.,Tianjin University of Technology | Song Z.L.,Tianjin University of Technology | Liang B.C.,Tianjin University of Technology | Zhou X.B.,North China Pharmaceutical Corporation | Yang Z.H.,North China Pharmaceutical Corporation
Chemical Engineering Research and Design | Year: 2010

This paper presents an experimental investigation on the crystallization of cobalamine (vitamin B12) under different operating conditions and crystallization methods. A systematic analysis of the effects of cooling rate, stirring speed and solvent on the metastable zone and quality of crystals is presented. Focused beam reflectance measurement probe is used for in situ particle size analysis. The process of crystallization is observed by FBRM. The influence of four typical ionic impurities (Na+, Mg2+, Ca2+, and Fe3+) on cobalamine crystallization is also studied. From the observation of crystals by SEM, it is clear that Fe3+ and Mg2+ have significant effect on crystal morphology, while Na+ and Ca2+ have a little. © 2009 The Institution of Chemical Engineers. Source

Zhang S.-X.,North China Pharmaceutical Corporation | Cheng L.-J.,North China Pharmaceutical Corporation
Chinese Journal of Biologicals | Year: 2012

Objective: To develop a more sensitive and effective method for differentiation of glycoprotein by staining. Methods: An improved gel staining method was developed based on periodic acid-Schiff method by optimizing the formula of fixing, reduction and oxidation solutions as well as time for staining, and compared with periodic acid-Schiff method. Results: Samples of recombinant monoclonal antibody were stained by the improved method, and the result showed that only the heavy chain was stained, while the light chain was unstained. However, after counter-stain with Coomassie brilliant blue, both heavy and light chains were stained. The sensitivity of the improved method for determination of sugar content was 0.15 μg, while that of traditional periodic acid-Schiff method was 3 μg. Conclusion: A novel method for differentiation of glycoprotein by staining was successfully developed, which was highly specific, sensitive and time-saving. Source

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