Complex Ca2+ flux inhibition as primary mechanism of staurosporine-induced impairment of T cell activation.
The inhibitory effect of the highly effective drug staurosporine on the early activation signal Ca2+ flux was investigated via multiparameter flow cytometry in human peripheral blood T lymphocytes. Staurosporine has been reported to be a specific inhibitor of protein kinase C. However, we show that it inhibits the Ca2+ influx in anti-CD3 and phytohemagglutinin-stimulated human CD4+ and CD8+ lymphocytes at concentrations between 1.0 and 10.0 ng/ml. Staurosporine decreases the number of Ca2+-positive CD4+ and CD8+ lymphocytes as well as the Ca2+ influx per cell; the drug also delays the time of the maximum response to polyclonal stimulation. In addition, we demonstrate that staurosporine affects the primary Ca2+ response via inhibition of the release of the membrane-bound Ca2+ from the endoplasmic reticulum in CD4+ and CD8+ lymphocytes. Binding studies of the anti-CD3 antibody to T lymphocytes indicate normal binding capacities in the presence of staurosporine. With respect to the classical scheme of T cell activation via phospholipase C, our data suggest that staurosporine may inhibit T cell activation primarily by its effect on the early Ca2+ flux signal.
Kubbies
M
M
Research Center, Boehringer Mannheim GmbH, Penzberg, FRG.
Goller
B
B
Russmann
E
E
Stockinger
H
H
Scheuer
W
W
D000470:Alkaloids / Q000494:pharmacology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology / Q000502:physiology; D017252:CD3 Complex; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D016827:CD8 Antigens; D002118:Calcium / Q000502:physiology*; D002451:Cell Compartmentation / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D007211:Indoles; D008213:Lymphocyte Activation / Q000187:drug effects*; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D019311:Staurosporine; D013601:T-Lymphocytes / Q000502:physiology*; D013997:Time Factors
D000470:Alkaloids; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D016827:CD8 Antigens; D007211:Indoles; D011948:Receptors, Antigen, T-Cell; D019311:Staurosporine; C048960:indo-1; D002118:Calcium