Three-dimensional structure of the complex between a T-cell receptor b chain and the superantigen staphylococcal entorotoxin B

LI, HM; LLERA ANDREA S; TSUCHIYA, D; LEDER L; YSERN X; SCHILIEVERT, PM; KARJALAINEN, K; MARIUZZA, R

IMMUNITY

Año: 1998 vol. 9 p. 807 - 816

1074-7613

Superantigens(SAGs) are a class of immunostimulatory proteins of bacterial or viral origin that activate Tcells by binding to the Vb domain of the T cell antigen receptor (TCR). The three-dimensional structure of the complex between a TCR b chain (mouse Vb8.2) and the SAG staphylococcal enterotoxin B (SEB) at 2.4 A°resolution reveals why SEB recognizes only certain Vb families, as well as why only certain SAGs bind mouse Vb8.2. Models of the TCR-SEB-peptide/MHC class II complex indicate that Va interacts with the MHC b chain in the TCR-SAG-MHC complex. The extent of the interaction is variable and is largely determined by the geometry of Va/Vb domain association. This variability can account for the preferential expression of certain Va regions among T cells reactive with SEB.