Clonal deletion of postthymic T cells: veto cells kill precursor cytotoxic T lymphocytes.
Veto cell-mediated suppression of cytotoxic T lymphocyte (CTL) responses has been proposed as one mechanism by which self-tolerance is maintained in mature T cell populations. We have previously reported that murine bone marrow cells cultured in the presence of high-dose interleukin 2 (IL-2) (activated bone marrow cells [ABM]) mediate strong veto suppressor function. To examine mechanisms by which ABM may suppress precursor CTL (p-CTL) responses, we used p-CTL generated from spleen cells of transgenic mice expressing a T cell receptor specific for H-2 Ld. It was demonstrated that the cytotoxic response by these p-CTL after stimulation with irradiated H-2d/k spleen cells was suppressed by DBA/2 (H-2d) ABM, but not by B10.BR (H-2k) ABM or dm1 (Dd, Ld mutant) ABM. Flow cytometry analysis with propidium iodide staining revealed that these p-CTL were specifically deleted by incubation with H-2d ABM, but not with H-2k ABM. These data indicate that ABM veto cells kill p-CTL with specificity for antigens expressed on the surface of the ABM, and that the mechanism for veto cell activity of ABM is clonal deletion of p-CTL.
Hiruma
K
K
Experimental Immunology Branch, National Cancer Institute, Bethesda, Maryland 20892.
Nakamura
H
H
Henkart
P A
PA
Gress
R E
RE
D000818:Animals; D001854:Bone Marrow Cells; D002999:Clone Cells / Q000276:immunology; D000939:Epitopes; D007376:Interleukin-2 / Q000494:pharmacology; D008212:Lymphocyte Depletion; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*
D000939:Epitopes; D007376:Interleukin-2