Superantigen staphylococcal enterotoxin B-induced T-helper cell activation is independent of CD4 molecules and phosphatidylinositol hydrolysis.
The role of the CD4 molecule in activation of T-helper cells was examined by investigating the effect of an anti-CD4 monoclonal antibody (Leu3a) in conventional peptide antigen-specific cloned T-helper cells that are also reactive to staphylococcal enterotoxin B (SEB). These T-helper cell clones are CD4+/CD45RO+/T-cell antigen receptor beta-chain variable region 12-positive and can respond to nominal peptide antigens and SEB by proliferation in the presence of class II major histocompatibility complex-expressing accessory cells. Although antigen and SEB were comparable in their ability to induce proliferative responses, interleukin 2 (IL-2) production, and IL-2 receptor alpha-chain expression, stimulation with SEB failed to trigger phosphatidylinositol hydrolysis or a rise in the intracellular free calcium ion concentration. Leu3a treatment inhibited antigen-induced proliferative responses of T cells with concomitant suppression of IL-2 production and IL-2 receptor expression. In contrast, SEB-induced responses were unaffected by Leu3a. These findings indicate that the functional consequences of binding (ligation) of conventional antigen and of superantigen with the T-cell receptor are distinct in the context of both signal transduction pathways and participation of CD4 molecules.
Oyaizu
N
N
Department of Pediatrics, North Shore University Hospital-Cornell University Medical College, Manhasset, NY 11030.
Chirmule
N
N
Yagura
H
H
Pahwa
R
R
Good
R A
RA
Pahwa
S
S
D000911:Antibodies, Monoclonal / Q000276:immunology; D000941:Antigens / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004768:Enterotoxins / Q000276:immunology*; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D010716:Phosphatidylinositols / Q000502:physiology; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D015290:Second Messenger Systems; D015398:Signal Transduction; D013211:Staphylococcus aureus / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000941:Antigens; D000942:Antigens, Bacterial; D004768:Enterotoxins; D007376:Interleukin-2; D010716:Phosphatidylinositols; D015375:Receptors, Interleukin-2; C031818:enterotoxin B, staphylococcal; D002118:Calcium