ABSTRACT
@#Objective To analyze the correlation of different methods for the detection of antibody titer after immunization with severe acute respiratory symptom corona virus 2(SARS-CoV-2) vaccine,and provide a methodological basis for the specific antibody detection.Methods The seroconversion rate of IgG antibody and neutralizing antibody titer of SARS-CoV-2 inactivated vaccine clinical trial serum samples were detected by micro-cell neutralization assay and three ELISA methods(using S protein,N protein and inactivated whole virus particles as antigens respectively),and the correlation among the methods was analyzed.Results The seroconversion rates detected by neutralizing antibody,S antibody,N antibody and whole virus antibody were 84.3%,91.3%,65.2% and 46.6%,and the geometric mean titers were 16.6,945.9,72.7 and 18.8,respectively.The correlation coefficients(r) between the results of three ELISA methods(using S protein,N protein and inactivated whole virus particles as antigens) and micro-cell neutralization assay were 0.494,0.371 and 0.181respectively.Conclusion Detection of SARS-CoV-2 S antibody level reflected the activation of the humoral immune response characterized by elevated antibody level to a great extent.