Longitudinal Observation of Antibody Dynamics in Three COVID-19 Patient against Four Structural SARS-CoV2 Proteins

Proper understanding of antibody dynamics and persistence of neutralizing antibodies will provide us the knowledge required for designing successful vaccine. Disappearance of antibody, absence of humoral immunity activation, sporadic cases of reinfection emphasize the importance of longitudinal antibody dynamic against variable structural antigens. In this study, we followed the antibody dynamics of three subjects over a period of 120 days by analyzing 512 samples. Among the three subjects, subject-1 (S01), has had previous infection with SARS-CoV during the 2003 epidemic. During the study period, all the subjects presented COVID-19 like symptoms twice, firstly mild symptoms followed by severe symptoms presentation. The initial episode did not culminate with any antibody development other than mild development of IgG against SARS-CoV-2 nucleocapsid. The second episode was characterized with multifold increase in IgG antibodies against the four SARS-CoV-2 proteins, but varied among individuals for IgM and IgA. Antibody dynamics in S01 and S02 highly correlated while that of S03 slightly differed, which may have been due to the unsupervised medicine regimen S03 opted for during the study period. Interestingly, antibody development for all subjects highly correlated with the severity of the symptoms.