Isolation, identification and immunogenicity of various coxsackievirus A16 particles

GUO Hui-jie; LU Wei-wei; HAO Chun-sheng; MA Shu-hua; LIU Shao-hua; ZHANG Wei-qing; ZHAO Zhong-xiang; LI Xiu-ling

Abstract：Objective: To prepare different forms of CA16 virus particles and to analyze their immunogenicity.Methods: The sucrose density gradient ultracentrifugation and anion exchange chromatography were used to isolate and purify CA16 virus. The corresponding components were collected and the contents of antigen and protein in each component were determined. SDS-PAGE, Western Blot, and electron microscopy were used for identification.Mice were immunized with different isolated virus particle fractions respectively and injected intraperitoneally 3 times at 0 d, 14 d, and 28 d. Blood was collected on day 14 after the last immunization and serum was separated.The neutralizing antibody titers were detected by the cytopathic effect-based neutralization assay. Results: After the virus were subjected by ultracentrifugation and anion exchange chromatography, two forms of virus particles, EP and FP, could be isolated. Under electron microscope, EP showed hollow particles and FP was solid particles.SDS-PAGE results showed that VP0, VP1 and VP3 protein bands were observed in EP, and VP1, VP2 and VP4 protein bands were observed in FP. After the mice immunized with EP and FP, neutralizing antibodies against CA16 virus were induced, but the level of neutralizing antibodies induced by EP was much lower than that of FP.There was a statistical difference between them. Conclusion: In the cell culture, there are two types of virus particles EP and FP, both of which have immunogenicity. But the immunogenicity of FP is higher than that of EP.