Transfer of SARS-CoV-2–specific immunity to MM patient by convalescent plasma infusion and subsequent viral clearance. (A) IgM and IgG antibody responses in patient ID359 plasma against SARS-CoV-2 proteins and control proteins at 1:20 serum dilution before and after convalescent plasma infusion, as determined by ELISA. (B) IgM and IgG responses at 1:20 plasma dilution against SARS-CoV-2 and control proteins in convalescent plasma product, as determined by ELISA. (C) Reciprocal IgG antibody titers against SARS-CoV-2 and control proteins and neutralizing antibody titers in the convalescent plasma product. (D) Epitope mapping of convalescent plasma product and plasma from a healthy donor (HD1) using synthetic S1 peptides, as determined by ELISA. 20mer peptides overlapping by 10 aa for SARS-CoV-2 S1, S2, M, and E sequences were synthetized (peptides & elephants, Hennigsdorf, Germany). Data represent the mean, and circles indicate technical replicates. (E) Reciprocal IgG titers against SARS-CoV-2 proteins and FLU, as well as neutralizing antibody activity in patient ID359 plasma, before and after convalescent plasma infusion. Antibody titers represent mean ± standard deviation from 2 technical replicates. GST, glutathione-S-transferase; neg, negative.