Antibodies in longitudinal blood donor samples suggest long-term memory against SARS-CoV-2

Antibody responses in longitudinal samples from donors point towards long-term memory after SARS-CoV-2 infection. That’s what Sanquin Research reports in the journal Clinical & Translational Immunology.

The researchers, led by Theo Rispens, performed a quantitative analysis of 844 individual longitudinal samples from 151 PCR-positive convalescent adults. Anti-receptor-binding domain IgG and antinucleocapsid IgG levels declined with median half-lives of 62 and 59 days, respectively, 2–5 months after symptom onset. Most importantly, the rate of decline of antibody levels diminished during extended follow-up, suggesting long-term memory against the coronavirus.

Donors were followed during the first 250 days after onset of symptoms, using a median of 5 (range 2–18) samples per individual.

The magnitude of the anti-RBD IgG response correlated well with neutralization capacity measured in a classic plaque reduction assay and in an in-house developed competition assay.

Quantitative and longitudinal

This analysis of the antibody response to SARS-CoV-2 infection, that is both quantitative and longitudinal, is of importance for serosurveillance purposes and for treatment options such as transfusion with convalescent plasma or immunoglobulin products derived from convalescent plasma.