Differential CD3/T cell antigen receptor-mediated IL-2 production in jurkat T cells. Dissociation of IL-2 response from total inositol phosphate and calcium responses.
We used three anti-human anti-CD3 mAb each recognizing different surface CD3 epitopes to differentially perturb the CD3/TCR complex on the surface of Jurkat T cells. In the presence of phorbol ester, these anti-CD3 mAb triggered differential IL-2 production in Jurkat T cells, which could not be explained by differences in kinetics of IL-2 production, by differences in IL-2 adsorption caused by differential surface expression of p55 or p75 IL-2R, by effects on IL-2 secretion rather than actual synthesis, or by differential toxicities of the anti-CD3 mAb to Jurkat cells. In addition, this differential anti-CD3-induced IL-2 production could not be explained by differences in mAb isotype or in avidities of the anti-CD3 mAb for the Jurkat cells. Moreover, anti-CD3 mAb covalently immobilized onto beads also differentially induced IL-2 production in Jurkat cells, suggesting that the differential IL-2 response is not based on differential rates of anti-CD3-induced modulation of Jurkat cell surface CD3. Although differences among the anti-CD3 mAb in the initial rates of binding to Jurkat cell were observed, this was also believed unlikely to explain the differential IL-2 response. Regardless of the anti-CD3 mAb used, anti-CD3-induced total inositol phosphate (IP) production did not necessarily correlate with anti-CD3-induced IL-2 production. Nevertheless, despite the differences among the anti-CD3 mAb in inducing IL-2 production, the calcium responses were grossly similar. Taken together, these observations indicate that CD3/TCR-mediated IL-2 production in Jurkat cells can be dissociated from total IP generation, and the basis of differential CD3/TCR-mediated IL-2 production in these cells does not appear to be at the level of the initial activation-induced calcium response. These studies suggest that the nature of the CD3/TCR ligand (its physical form and/or the specific epitope it perturbs) can either directly influence intracellular events distal to the generation of IP and increase in intracellular free calcium leading to differential IL-2 production or can trigger IP-independent pathways that affect IL-2 production.
Stohl
W
W
Department of Medicine, University of Southern California School of Medicine, Los Angeles 90033.
Hofman
F M
FM
Gray
J D
JD
D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology / Q000502:physiology*; D017252:CD3 Complex; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism*; D007376:Interleukin-2 / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000502:physiology*
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D007295:Inositol Phosphates; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D019204:GTP-Binding Proteins; D002118:Calcium