Does staphylococcal enterotoxin B bind directly to murine T cells?
We have investigated the binding potential of staphylococcal enterotoxin B (SEB) to murine T cells using the induction of early activation events in Th1 and Th2 T-cell clones in the absence of antigen-presenting cells (APC) as indicators of direct interactions between SEB and the T-cell receptor (TcR). We consistently found that concanavalin A (Con A) induced rises in intracellular free calcium as well as inositol phosphate accumulation in APC-free T-cell clones. However, SEB uniformly failed to induce either calcium fluxes or inositol phosphate turnover in Th1 and Th2 T-cell clones in the absence of APC. In addition, we have used proliferation assays to show that (i) T-cell clones prepulsed with SEB did not respond when APC were added, (ii) APC-independent T-cell clones responded to soluble anti-TcR antibodies but not to SEB in the absence of APC, and (iii) SEB coupled to Sepharose beads did not stimulate T-cell clones in the absence of APC. Taken together our results argue against SEB binding to the TcR without the participation of MHC class II molecules.
Qasim
W
W
Department of Immunology, Medical School, University of Newcastle upon Tyne, U.K.
Kehoe
M A
MA
Robinson
J H
JH
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D002118:Calcium / Q000378:metabolism; D002455:Cell Division / Q000276:immunology; D002999:Clone Cells / Q000276:immunology; D004768:Enterotoxins / Q000378:metabolism*; D007295:Inositol Phosphates / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*
D004768:Enterotoxins; D007295:Inositol Phosphates; D011948:Receptors, Antigen, T-Cell; C031818:enterotoxin B, staphylococcal; D002118:Calcium