新西兰兔对SARS-CoV实验灭活疫苗的体液免疫应答

Humoral immune responses in rabbits with an experimental SARS-CoV inactivated vaccine

目的:评价SARS-CoV广东F69分离株实验灭活疫苗的免疫效果。方法:病毒悬液经0·4%甲醛灭活后作为抗原,对新西兰兔进行免疫接种;采用ELISA法和微量细胞中和试验,检测血清特异性IgG抗体和中和抗体的消长规律。结果:初次免疫后第3天,即能检测到抗SARS-CoV特异性抗体,第7天检测到中和抗体。二次免疫后,特异性IgG抗体和中和抗体效价于第6周左右分别达到1∶81920和1∶20480的峰值水平。继续加强免疫,特异性抗体水平无明显变化。F69分离株与Z2-Y3广东分离株之间能够完全交叉中和。结论:F69毒株实验灭活疫苗具有很强的免疫原性。F69与Z2-Y3毒株之间尽管存在基因序列差异,但能够完全交叉免疫保护。

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 humorsl 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.