IgG antibody response against nucleocapsid and spike protein post-SARS-CoV-2 infection

• Published in: Infection 2021-10, Vol.49 (5), p.1045-1048
• Main Authors: Choudhary, Hari Ram, Parai, Debaprasad, Dash, Girish Chandra, Peter, Annalisha, Sahoo, Subrat Kumar, Pattnaik, Matrujyoti, Rout, Usha Kiran, Nanda, Rashmi Ranjan, Pati, Sanghamitra, Bhattacharya, Debdutta
• Format: Article
• Language: English
• Subjects: Antibodies; Antibodies, Viral; Antibody Formation; Antibody response; Antigens; Brief Report; Coronaviruses; COVID-19; Epidemiology; Family Medicine; General Practice; Humans; IgG antibody; Immunoglobulin G; Infectious Diseases; Internal Medicine; Medicine; Medicine & Public Health; Nucleocapsid; Nucleocapsids; Observational studies; Pandemics; Polymerase chain reaction; Proteins; Public health; RNA-directed DNA polymerase; SARS-CoV-2; Sensitivity and Specificity; Severe acute respiratory syndrome coronavirus 2; Spike Glycoprotein, Coronavirus; Spike protein; Viral diseases
• ISSN: 0300-8126; 1439-0973
• DOI: 10.1007/s15010-021-01651-4

Objectives Coronavirus disease-19 (COVID-19) pandemic became the greatest public health challenge globally. Study of dynamicity and durability of naturally developed antibodies against SARS-CoV-2 are of great importance from an epidemiological viewpoint. Methods In this observational cohort study, we have followed up the 76 individuals who tested positive for SARS-CoV-2 infection by real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) for 16 weeks (post-enrolment) to record the periodic changes in titre, concentration, clinical growth and persistence of naturally developed SARS-CoV-2 antibodies. We collected serum samples from these individuals for 16 weeks with a frequency of weekly and fortnightly during each follow-up and tested them in two CLIA-based platforms (Abbott Architect i1000SR and Roche Cobas e411) for testing SARS-CoV-2 antibodies both qualitatively and quantitatively. Results We recorded the antibody magnitude of these individuals 10 times between September 2020 and February 2021. We found a waning of antibodies against nucleocapsid antigen protein but not a complete disappearance by the end of 16 weeks. Out of 76 cases, 30 cases (39.47%) became seronegative in qualitative assay, although all the sera samples (100%) remained positive when tested in quantitative assay. Conclusion The lower persistence of anti-nucleocapsid SARS-CoV-2 antibody may not be the exact phenomenon as those cases were still seropositive against spike protein and help in neutralising the virus.