CD81 Monoclonal Antibody [1.3.3.22]CD81 Monoclonal Antibody (1. 3. 3. 22) is an IgG1 mouse monoclonal CD81 antibody (also designated CD81 antibody or TAPA1 antibody). CD81 Monoclonal Antibody (1. 3. 3. 22) is validated in applications, including ICC IF, Flow Cyt. CD81 (TAPA 1, target of anti proliferative antibody 1) is a member of the tetraspanin family, is expressed on virtually all nucleated cells, but above all on germinal center B cells. CD81 forms complexes with other tetraspanin