Potent apoptotic signaling and subsequent unresponsiveness induced by a single CD2 mAb (BTI-322) in activated human peripheral T cells.
Manipulation of CD2 molecules with CD2 mAb pairs has been shown to deliver apoptotic signals to activated mature T cells. We show that BTI-322, a CD2 mAb directed at a peculiar epitope of CD2, can trigger on its own the apoptotic death of IL-2-activated peripheral T cells and of OKT3-stimulated T cells, contrasting in this respect with a series of other mouse or rat CD2 mAb. F(ab')2 fragments were as potent as the whole Ab. BTI-322-induced apoptosis proceeded in a few hours and was independent of the Fas/Fas ligand system. Less than 5 ng/ml of BTI-322, added at the beginning of culture, were able to eliminate within 4 days most CD3+ cells from OKT3- and IL-2-stimulated lymphocytes, the only cells remaining being CD16+CD2- NK cells. T cell proliferative responses induced by a mitogenic CD2 mAb pair or by PHA-P (which mainly binds to CD2) were not inhibited by BTI-322. In this case, the apoptotic effect was successfully counteracted by simultaneous enhancement of T cell divisions. Thus, the killing effect of BTI-322 was most effective when T cells were exclusively stimulated through the CD3/TCR complex. Apoptosis of the responding T cells may explain why T cells recovered from a primary MLC performed in the presence of BTI-322 responded to third party cells but not to the primary stimulatory cells. These data constitute the rational basis for the use of BTI-322 for inducing tolerance in human allotransplantation.
Dumont
C
C
Centre National de Recherche Scientifique, UPR 420, Villejuif, France.
Déas
O
O
Mollereau
B
B
Hebib
C
C
Giovino-Barry
V
V
Bernard
A
A
Hirsch
F
F
Charpentier
B
B
Senik
A
A
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis / Q000276:immunology*; D018801:CD2 Antigens; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D051379:Mice; D051381:Rats; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D018801:CD2 Antigens; D017260:Receptor-CD3 Complex, Antigen, T-Cell