Development of Anti-idiotypic Monoclonal Antibody Mimicking SARS-CoV-2 Receptor Binding Domain.

Using the hybridoma technique, we developed a panel of anti-idiotypic monoclonal antibodies (aId-mAb) that mimic The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Receptor-Binding Domain (RBD) molecule against Fragment antigen-binding (Fab) of anti-SARS-CoV-2 (S1, RBD) antibodies. Investigated the in vivo and in vitro effects of these aId-mAbs we developed and examined their antigenic mimicry abilities. Among these 12 antibodies, 6 aId-mAbs (designated FY1B4, FY2A6, H9F3, E6G7, FY7E11, and FY8H3) were selected for further characterization in a series of experiments. First, competitive receptor binding assay results confirmed that six aId-mAbs could specifically bind to the ACE2 receptor in target cells and block the interaction between the RBD molecule and the ACE receptor. Moreover, we examined the immunological activities of these aId-mAbs in female BALB/c and showed that E6G7, H7E11, and H8H3 aId-mAbs induce an antibody response by mimicking RBD and stimulating the immune system. It is considered that these three aId-mAbs will be evaluated as SARS-CoV-2 vaccine candidate molecules in future studies.