A human monoclonal antibody bivalently binding two different epitopes in streptococcal M protein mediates immune function.

ABSTRACT: Group A streptococci have evolved multiple strategies to evade human antibodies, making it challenging to create effective vaccines or antibody treatments. Here, we have generated antibodies derived from the memory B cells of an individual who had successfully cleared a group A streptococcal infection. The antibodies bind with high affinity in the central region of the surface-bound M protein. Such antibodies are typically non-opsonic. However, one antibody could effectively promote vital immune functions, including phagocytosis and in vivo protection. Remarkably, this antibody primarily interacts through a bivalent dual-Fab cis mode, where the Fabs bind to two distinct epitopes in the M protein. The dual-Fab cis-binding phenomenon is conserved across different groups of M types. In contra

SUBMITTER: Bahnan W 

PROVIDER: S-EPMC9906385 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature