Inhibition of the CD3-mediated calcium signal by protein kinase C activators in human T (Jurkat) lymphoblastoid cells.
The changes in the cytoplasmic free calcium concentrations (Cai) were investigated in human T (Jurkat) lymphoblastoid cells, loaded with the calcium-sensitive fluorescent dye Indo-1. A rapid increase in Cai could be evoked by monoclonal antibodies (mAb) directed against the CD3 antigen, as well as by the mitogenic lectin concanavalin A (conA). The protein kinase C (pKC) activators TPA and DiC8 did not increase Cai, but the addition of any of these two compounds prior to mAb eliminated the mAb-induced calcium signal. In contrast, the calcium signal evoked by ConA was not blocked by TPA or DiC8. These results suggest that the CD3-dependent calcium signal is selectively down-regulated by the activation of pKC.
Tordai
A
A
National Institute of Haematology and Blood Transfusion, Budapest, Hungary.
Sarkadi
B
B
Görög
G
G
Gárdos
G
G
D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology*; D002460:Cell Line; D003864:Depression, Chemical; D004075:Diglycerides / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D005989:Glycerides / Q000494:pharmacology*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D011493:Protein Kinase C / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D015398:Signal Transduction / Q000187:drug effects*; D013601:T-Lymphocytes / Q000187:drug effects*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000945:Antigens, Differentiation, T-Lymphocyte; D004075:Diglycerides; D005989:Glycerides; D011948:Receptors, Antigen, T-Cell; C044295:1,2-dioctanoylglycerol; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium