Humoral immune responses in rabbits with an experimental SARS-CoV inactivated vaccine / 中国免疫学杂志

ABSTRACT

Objective:To evaluate the immunogenicity of an experimental SARS-CoV inactivated vaccine.Methods:The virus suspension of F69 strain was inactivated with 0.4% formaldehyde and purified,then used as the immune antigen combined with Freund′s adjuvant.Eight adult New Zealand rabbits were immunized 4 times with this vaccine.12 sets of rabbit serum were sampled from the third day to 74th day after first immunization.Titers of specific IgG antibody and neutralizing antibody were determined by indirect ELISA and micro-cytopathic effect neutralizing test.Results:Rapid and potent humoral immune responses were induced by F69 inactivated vaccine in all eight immunized rabbits.Both specific IgG antibody and neutralizing antibody all peaked just with 2 vaccinations,with the maximum titer of 1∶81 920 and 1∶20 480 respectively about 6 weeks after first immunization.Across neutralizing reaction existed between F69 and Z2-Y3 strains.Conclusion:F69 inactivated vaccine owns strong immunogenicity.Similar antigenic epitopes exist between the F69 strain and Z2-Y3 strain,which ensured the cross neutralizing reaction.