Intracellular calcium levels are differentially regulated in T lymphocytes triggered by anti-CD2 and anti-CD3 monoclonal antibodies.
Antigen and/or mitogen-driven T-cell activation is mediated by a rise in intracellular free Ca2+, as second messenger. A regulatory key role for this process is represented by membrane-associated [Ca2+/Mg2+] ATP-ase that is mainly devoted to extrusion of intracellular ion excess. In the present study we have investigated the kinetics of CA2+ fluxes in both resting and already activated (Jurkat T-cell line) T lymphocytes after CD3 and CD2 (T11(2) and T11(3)) triggering and focused our attention on plasma membrane [Ca2+/Mg2+] ATP-ase activity. In both resting T cells and Jurkat cell line, the CD2 stimulation was able to determine a rise in intracellular free Ca2+ higher than that observed after CD3 triggering. In addition, this calcium signal was independent of negative feedback control exerted by [Ca2+/Mg2+] ATP-ase, as well as of IP3 generation. Thus the CD2 molecular system may, together with cell-adhesion properties, act as an amplifier of Ca2+ signals that, if delivered in the context of other molecular systems, such as CD3 or MHC class II antigens, are essentially devoted to the polyclonal co-stimulatory recruitment of a larger cellular repertoire.
Spinozzi
F
F
Department of Internal Medicine, University of Perugia, Italy.
Agea
E
E
Bistoni
O
O
Belia
S
S
Travetti
A
A
Gerli
R
R
Muscat
C
C
Bertotto
A
A
D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D018801:CD2 Antigens / Q000276:immunology / Q000502:physiology*; D017252:CD3 Complex / Q000276:immunology / Q000502:physiology*; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D018801:CD2 Antigens; D017252:CD3 Complex; D004533:Egtazic Acid; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium