Soluble human MHC class I molecules induce soluble Fas ligand secretion and trigger apoptosis in activated CD8(+) Fas (CD95)(+) T lymphocytes.
In the present study, we have evaluated the apoptotic effect of soluble human MHC class I (sHLA-I) antigens on CD8(+) T lymphocytes. sHLA-I antigens and beta(2)-microglobulin-free HLA class I heavy chains, isolated from serum, induced apoptosis on phytohemagglutinin-activated CD8(+) T lymphocytes in autologous and allogeneic combinations. The extent of CD8(+) T cell apoptosis depends on the degree of activation, time of incubation with sHLA-I antigens and amount of sHLA-I antigens added to the cultures. Apoptosis is induced by the interaction of Fas (CD95)(+) cells with soluble Fas ligand which is released following binding of sHLA-I antigens to CD8 molecules. These results suggest that sHLA-I antigens may regulate immune responses by inducing apoptosis in activated CD8(+) T cells.
Puppo
F
F
Department of Internal Medicine, University of Genoa, Viale Benedetto XV no. 6, 16132 Genoa, Italy.
Contini
P
P
Ghio
M
M
Brenci
S
S
Scudeletti
M
M
Filaci
G
G
Ferrone
S
S
Indiveri
F
F
D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007118:Immunoassay; D008024:Ligands; D008213:Lymphocyte Activation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012995:Solubility; D019014:fas Receptor / Q000276:immunology / Q000378:metabolism*
D015395:Histocompatibility Antigens Class I; D008024:Ligands; D019014:fas Receptor