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Li C.,National Institutes for Food and Drug Control | Li C.,Collaborating Centers for Standardization and Evaluation of Biologicals | Xu K.,National Institutes for Food and Drug Control | Xu K.,Collaborating Centers for Standardization and Evaluation of Biologicals | And 16 more authors.
Human Vaccines and Immunotherapeutics | Year: 2015

The outbreak of human infections of a novel avian influenza virus A (H7N9) prompted the development of the vaccines against this virus. Like all types of influenza vaccines, H7N9 vaccine must be tested for its potency prior to being used in humans. However, the unavailability of international reference reagents for the potency determination of H7N9 vaccines substantially hinders the progress in vaccine development. To facilitate clinical development, we enlisted 5 participants in a collaborative study to develop critical reagents used in Single Radial Immunodiffusion (SRID), the currently acceptable assay for potency determination of influenza vaccine. Specifically, the hemagglutinin (HA) content of one vaccine bulk for influenza A (H7N9), herein designated as Primary Liquid Standard (PLS), was determined by SDS-PAGE. In addition, the freeze-dried antigen references derived from PLS were prepared to enhance the stability for long term storage. The final HA content of lyophilized antigen references were calibrated against PLS by SRID assay in a collaborative study. Importantly, application of these national reference standards to potency analyses greatly facilitated the development of H7N9 vaccines in China. © 2015, Taylor & Francis Group, LLC.

Liang Z.,Chinese National Institute for the Control of Pharmaceutical and Biological Products | Mao Q.,Chinese National Institute for the Control of Pharmaceutical and Biological Products | Gao Q.,Sinovac Biotech | Li X.,National Vaccine and Serum Institute | And 8 more authors.
Vaccine | Year: 2011

Enterovirus 71 (EV71) is a highly infectious agent that causes hand-foot-mouth disease (HFMD) in humans. Effective vaccination against EV71 infection is critically important, given the recent outbreak of HFMD in the Asia-Pacific region, where it has shown significant mortality and morbidity. There is currently no approved anti-viral therapy available to treat the disease. While several vaccine manufacturers are actively developing EV71 vaccines, there are no international reference standards available to conduct quality control on EV71 vaccines or to assess the effectiveness of EV71 vaccines in immunized populations. In the current report, antigen reference standard based on the C4 subtype of the EV71 vaccine strain was developed. In addition, neutralizing antibody (NTAb) reference panels were analyzed and standards with various neutralizing titers were selected. These reference antigens were used to calibrate vaccine samples from several producers and found that five EV71 antigens and the national reference standards showed good linearity and parallelism. Moreover, mice immunized with various vaccines at doses standardized by these national references showed comparable NTAb responses. Finally, the national NTAb reference panels were found to effectively reduce assay discrepancy between different labs. Taken together, these national reference standards are highly valuable for the standardization and evaluation of EV71 vaccines. © 2011 Elsevier Ltd.

Lu P.,Nanjing Agricultural University | Zheng L.-Q.,Yunnan University | Zheng L.-Q.,Hualan Biological Engineering Inc. | Sun J.-J.,Nanjing Agricultural University | And 4 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2012

The taxonomic status of a methyl-parathion-degrading strain, OP-1T, isolated from a wastewater-treatment system in China, was determined using a polyphasic approach. The rod-shaped cells were Gram-staining-negative, non-spore-forming and non-motile. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain belonged to the genus Burkholderia, as it appeared closely related to Burkholderia glathei ATCC 29195T (97.4 % sequence similarity), Burkholderia sordidicola KCTC 12081T (96.5 %) and Burkholderia bryophila LMG 23644T (96.3 %). The major cellular fatty acids, C16: 0, C17: 0 cyclo and C18: 1ω7c, were also similar to those found in established members of the genus Burkholderia. The genomic DNA G+C content of strain OP-1T was 59.4 mol%. The level of DNA-DNA relatedness between the novel strain and the closest recognized species, Burkholderia glathei ATCC 29195T, was only 30 %. Based on the phenotypic, genotypic and phylogenetic evidence, strain OP-1T represents a novel species of the genus Burkholderia, for which the name Burkholderia zhejiangensis sp. nov. is proposed. The type strain is OP-1T (= CCTCC AB 2010354T = KCTC 23300T). © 2012 IUMS.

Wu X.,Peking University | Wu X.,National Institutes for Food and Drug Control | Mao Q.,National Institutes for Food and Drug Control | Yao X.,National Institutes for Food and Drug Control | And 11 more authors.
PLoS ONE | Year: 2013

The level of neutralizing antibodies (NtAb) induced by vaccine inoculation is an important endpoint to evaluate the efficacy of EV71 vaccine. In order to evaluate the efficacy of EV71 vaccine, here, we reported the development of a novel pseudovirus system expression firefly luciferase (PVLA) for the quantitative measurement of NtAb. We first evaluated and validated the sensitivity and specificity of the PVLA method. A total of 326 serum samples from an epidemiological survey and 144 serum specimens from 3 clinical trials of EV71 vaccines were used, and the level of each specimen's neutralizing antibodies (NtAb) was measured in parallel using both the conventional CPE-based and PVLA-based assay. Against the standard neutralization assay based on the inhibition of the cytopathic effect (CPE), the sensitivity and specificity of the PVLA method are 98% and 96%, respectively. Then, we tested the potential interference of NtAb against hepatitis A virus, Polio-I, Polio-II, and Polio-III standard antisera (WHO) and goat anti-G10/CA16 serum, the PVLA based assay showed no cross-reactivity with NtAb against other specific sera. Importantly, unlike CPE based method, no live replication-competent EV71 is used during the measurement. Taken together, PVLA is a rapid and specific assay with higher sensitivity and accuracy. It could serve as a valuable tool in assessing the efficacy of EV71 vaccines in clinical trials and disease surveillance in epidemiology studies. © 2013 Wu et al.

Chen X.,CAS Institute of Process Engineering | Chen X.,University of Chinese Academy of Sciences | Liu Y.,Beijing University of Chemical Technology | Wang L.,CAS Institute of Process Engineering | And 9 more authors.
Molecular Pharmaceutics | Year: 2014

Surface-engineered particulate delivery systems for vaccine administration have been widely investigated in experimental and clinical studies. However, little is known about charge-coated microspheres as potential recombinant subunit protein antigen delivery systems in terms of adsorption and related immune responses. In the present study, cationic polymers, including chitosan (CS), chitosan chloride (CSC), and polyethylenimine (PEI), were used to coat PLA microspheres to build positively charged surfaces. Antigen adsorption capacity was enhanced with increased surface charge of coated microspheres. In macrophages, HBsAg adsorbed on the surface of cationic microspheres specifically enhanced antigen uptake and augmented CD86, MHC I, and MHC II expression and IL-1β, IL-6, TNF-α, and IL-12 release. Antigens were more likely to localize independent of lysosomes after phagocytosis in antigen-attached cationic microsphere formulations. After intraperitoneal immunization, cationic microsphere-based vaccine formulations generated a rapid and efficient humoral immune response and cytokine release as compared with aluminum-adsorbed vaccine and free antigens in vivo. Moreover, microspheres coated with cationic polymers with relatively high positive charges and higher antigen adsorption exhibited strong stimulation of the Th1 response. In conclusion, PLA microspheres coated with cationic polymers may be a potential recombinant antigen delivery system to induce strong cell and humoral immune responses. © 2014 American Chemical Society.

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