ABSTRACT
Antigenic purity is important for quality control of the foot-and-mouth (FMD) whole virus inactivated vaccine. The recommended method for evaluation the antigenic purity of FMD vaccine is to check the serum conversion to non-structural protein (NSP) 3AB antibody after 2 to 3 times inoculation of animals with inactivated vaccine. In this study, we developed a quantitative ELISA to detect the amount of residual 3AB in vaccine antigen, to provide a reference to evaluate the antigenic purity of FMD vaccine. Monoclonal antibody (Mab) of NSP 3A and HRP-conjugated Mab of NSP 3B were used to establish a sandwich ELISA to quantify the NSP 3AB in vaccine antigen of FMD. Purified NSP 3AB expressed in Escherichia coli was serially diluted and detected to draw the standard curve. The detectable limit was determined to be the lowest concentration of standard where the ratio of its OD value to OD blank well was not less than 2.0. Results: The OD value was linearly corelated with the concentration of 3AB protein within the range between 4.7 and 600 ng/mL. The correlation coefficient R² is greater than 0.99, and the lowest detectable limit is 4.7 ng/mL. The amount of 3AB protein in non-purified inactivated virus antigen was detected between 9.3 and 200 ng/mL depending on the 12 different virus strains, whereas the amount of 3AB in purified virus antigen was below the lowest detectable limit. The amount of 3AB in 9 batches of commercial FMD vaccine antigens was between 9.0 and 74 ng/mL, whereas it was below the detectable limit in other 24 batches of commercial vaccine antigens. Conclusion: the sandwich ELISA established in this study is specific and sensitive to detect the content of 3AB protein in vaccine antigen of FMD, which will be a useful method for evaluation of the antigenic purity and quality control of FMD inactivated vaccine.
Subject(s)
Animals , Antibodies, Viral , Enzyme-Linked Immunosorbent Assay , Foot-and-Mouth Disease/prevention & control , Foot-and-Mouth Disease Virus , Viral Nonstructural Proteins/genetics , Viral VaccinesABSTRACT
We investigated the enhanced immune response of a recombinant T cell immunogen as an effective cellular immune adjuvant. The T cell immunogen named TI contained several T cell epitopes from the VP1, VP4, 3A and 3D proteins of foot-and-mouth disease virus (FMDV) and two pan-T helper (T(H)) cell sites to broaden the immunogenicity of the protein. Meanwhile, another fusion protein named OA-VP1 was expressed in bacteria, which contained two VP1 proteins of O and Asia1 type FMDV. Mice were vaccinated with commercially inactivated vaccine or OA-VP1 protein with or without the TI immunogen. The results show that mice inoculated with inactivated vaccine or OA-VP1 protein supplemented with TI immunogen produced significantly higher level of neutralizing antibodies (P < 0.01 or P < 0.05) than the mice only inoculated with inactivated vaccine or OA-VP1 protein by microneutralization assay. An obvious increase in T cell number by flow cytometric analysis and significantly higher concentration of IFN-gamma secreted in culture media of spleen lymphocytes were observed in groups supplemented with TI immunogen (P < 0.01). TI immunogen was an effective stimulator for humoral and cellular immunity and could help improve the immunogenicity of inactivated vaccine or protein subunit vaccine.
Subject(s)
Animals , Mice , Adjuvants, Immunologic , Pharmacology , Capsid Proteins , Genetics , Allergy and Immunology , Epitopes, T-Lymphocyte , Genetics , Allergy and Immunology , Foot-and-Mouth Disease , Allergy and Immunology , Virology , Foot-and-Mouth Disease Virus , Allergy and Immunology , Immunization , Viral Vaccines , Genetics , Allergy and Immunology , PharmacologyABSTRACT
To investigate the security of semen biologically, 15 bull semen samples were collected (of which 5 exhibited clinical signs of Foot-and-mouth disease) and identified by RT-PCR and virus isolation. The results indicated that the semen of the infected bulls were contaminated by Foot-and-mouth disease virus (FMDV), but FMDV was not detected in semen samples from those bulls not showing clinical signs of Foot-and-mouth disease (FMD). This is the first report of the presence of FMDV in bull semen due to natural infection in China. The analysis of the partial sequence of the VP1 gene showed that the virus strain isolated from semen has 97.9% identity with the virus isolated from vesicular liquid of infected bulls showing typical signs of FMD and belonged to the same gene sub-group.
ABSTRACT
High cell density culture of Lactobacillus plantaru is a significant step of the preparation of lactic acid bacteria starter.Firstly,this experiment is designed to analyze the effects of different dissolved oxygen and pH on the batch fermentation of Lactobacillus plantarum.And then,on the base of the batch fermentation,fed-batch fermentation was studied,companied by chemic neutralization in the experiment to achieve the aim of high cell density cultivation.Finally,in the comparison of two kinds of feeding mode for fed-batch operation in 10L fermentor,it was demonstrated that two kinds of feeding mode made cell concentration increase differently,in which pH feedback feeding can control sucrose concentration within a certain lower range,therefore obtaining the maximum cell concentration.With the pH feedback feeding,the dry cell weight was up to 13.56g/L,which increased 90.05% over that of batch culture.