Different pathways of human T-cell activation revealed by PHA-P and PHA-M.
Antigen-specific T-cell activation is mediated via the CD3-Ti (antigen receptor) complex, and monoclonal antibodies to both CD3 and Ti cause a rapid rise in intracellular Ca2+. This calcium mobilization is not inhibited by monoclonal antibodies to CD2. The rise in calcium mobilization induced by purified PHA (PHA-P) does not occur in a cell line which lacks CD2 expression, and can be blocked in other T cells by anti-CD2 antibodies. A combination of monoclonal antibodies to different epitopes of CD2 causes calcium mobilization and mitogenesis. Reagent grade PHA (PHA-M) induces calcium moblization in cells that lack CD2, and its effects in other T cells cannot be blocked by anti-CD2 antibodies. The effects of PHA-P and PHA-M are thus mediated predominantly through different activation pathways.
O'Flynn
K
K
Russul-Saib
M
M
Ando
I
I
Wallace
D L
DL
Beverley
P C
PC
Boylston
A W
AW
Linch
D C
DC
D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D000939:Epitopes; D006801:Humans; D008213:Lymphocyte Activation; D008938:Mitosis; D010835:Phytohemagglutinins / Q000494:pharmacology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D000939:Epitopes; D010835:Phytohemagglutinins; D011948:Receptors, Antigen, T-Cell; C047876:phytohemagglutinin-M; C028784:phytohemagglutinin-P; D002118:Calcium