Stimulation of the T3-T cell receptor complex induces a membrane-potential-sensitive calcium influx.
Three monoclonal antibodies selected for their recognition of parts of the T3-T cell receptor complex on human T lymphocytes were found to induce an increase in cytoplasmic free Ca2+ (Ca2+i) in the T cell leukemia line HPB-ALL as measured by Quin2 fluorescence. These reagents are directed against T3 (OKT3), a nonvariable T3-associated structure (WT-31) and the variable region of the T3-associated antigen receptor (T40/25) of this cell line. The rise in Ca2+i was dependent on the presence of extracellular Ca2+, occurred within 30 sec of stimulation, and was sustained for at least 10 min. Fab fragments of OKT3 also caused a rapid increase in Ca2+i, indicating that cross-linking is not necessary to induce a Ca2+ response. Alterations in plasma membrane potential and La3+ blocked the Ca2+ influx induced by OKT3 and T40/25. These data suggest that the T3-T cell receptor complex of human T lymphocytes may be an antigen-regulated Ca2+ channel.
Oettgen
H C
HC
Terhorst
C
C
Cantley
L C
LC
Rosoff
P M
PM
D000634:Aminoquinolines; D000911:Antibodies, Monoclonal / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004533:Egtazic Acid / Q000494:pharmacology; D005456:Fluorescent Dyes; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D007811:Lanthanum / Q000494:pharmacology; D007938:Leukemia; D008564:Membrane Potentials; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D013050:Spectrometry, Fluorescence; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology
D000634:Aminoquinolines; D000911:Antibodies, Monoclonal; D005456:Fluorescent Dyes; D007473:Ion Channels; D011948:Receptors, Antigen, T-Cell; D004533:Egtazic Acid; D007811:Lanthanum; C035739:Quin2; D002118:Calcium