Figure 7.

Longitudinal study of anti-RBD antibody response in COVID-19 recovered patients. Serum samples of 14 recovery patients were collected at t1 (3–17 days POS) and t2 (60–120 days POS). (a) Anti-RBD IgG titer was determined by RBD ELISA. Serum samples were incubated on plates coated with the RBD-mFc and were detected with an anti-human IgG conjugated to horseradish peroxidase (HRP). (b) Half-maximal inhibitory dilution (ID50) was determined by surrogate virus neutralization test (sVNT). Inhibition of binding of RBD-mFc to hACE2-hFc was assessed after pre-incubation of RBD-mFc with serum samples.