Monkeypox virus is an Orthopoxvirus, a genus that includes camelpox, cowpox, vaccinia, and variola viruses. B6R is the homolog of Vaccinia virus protein B5R. The B5R protein is required for the wrapping of IMV by intracellular membranes, EEV formation, normal plaque size, and virus virulence. B5R is conserved among different orthopoxviruses and B5 antibodies protect the host from vaccinia virus challenge by its neutralizing function, Anti-MPXV B6R mAb is a human monoclonal antibody human IgG1 and is produced by mammalian expression system.