A model B-cell superantigen and the immunobiology of B lymphocytes

Recent reports have shown that protein A of Staphylococcus aureus (SpA) is a specific toxin for B cells by virtue of specific binding interactions with conserved sites on the V(H) region of the B-cell antigen receptor. The structural basis for these Fab-binding interactions has recently been revealed in crystallographic analyses, which have demonstrated many similarities with the interactions of T-cell superantigens. Investigations of the in vivo response to SpA have illustrated how a B-cell superantigen can be used to provide a window for examining fundamental principles that underlie the immunobiology of B lymphocytes.