[Immunoprotective effect of inactivated coxsackievirus A16 vaccine in mice]

This study aims to construct inactivated coxsackievirus A16 (CVA16) vaccine and to investigate its protective effect in ICR mice. A clinical isolate of CVA16, 521-01T, was cultured in VERO cells, inactivated by formaldehyde, and purified by ultracentrifugation for vaccine preparation. Purity and other characteristics of the vaccine were determined by SDS-PAGE and Western blot. Female ICR mice were subcutaneously inoculated with inactivated CVA16 or Al(OH)3-absorbed CVA16, followed by booster immunization at the end of 2 and 4 weeks. CVA16-specific IgG titers in serum were determined by ELISA, and titers of neutralizing antibodies were determined by viral neutralization assay. The immunity of T lymphocytes was evaluated by IFN-gamma ELISPOT assay. The protective effect was evaluated by challenging the neonatal offspring (< 48 hours) of vaccinated female mice with 1 000 LD50 of CVA16 521-01T. The mortality rates of different groups were compared. The results showed that Al(OH)3 +CVA16 could induce high titers of specific IgG antibodies in ICR mice. After being boosted two times, the serum IgG antibody titer could reach up to 1 : 1 x 10(5) (P = 0.000), and neutralizing antibody titer was higher than 1 : 256. Additionally, more spot forming cells were induced in the immunized groups than in the negative controls. The maternal antibodies showed protective effect in 100% of the neonatal mice challenged with 1 000 LD50 of CVA16 521-01T. The inactivated CVA16 vaccine has ideal immunogenicity and immunoprotective effect. This research lays a foundation for the development and evaluation of CVA16 vaccines.