Induction of hyporesponsiveness in human lymphocytes-T despite their expression of both the co-receptor CD28 and its ligand B7.
A majority (42/62) of TCR2+ interleukin 2-dependent human T lymphocyte clones was found concordantly to express not only the CD28 co-receptor structure at the cell surface but also its ligand B7. Interactions between CD28 and B7 can have important consequences for T cell activation, particularly in providing "signal 2" to prevent the induction of anergy caused by stimulation via the antigen receptor only ("signal 1"). However, despite the expression of co-receptor and ligand on the same cell surface, it remained possible to induce hyporesponsiveness in T cell clones either when using CD3 antibodies to deliver signal 1 or when using other T cell clones as stimulators. Thus, the potential for intraclonal autostimulation via CD28/B7 is apparently insufficient to prevent downregulation of responsiveness in these two systems.
Friccius
H
H
Section for Transplantation Immunology and Immunohaematology, University of Tübingen, Germany.
Siegels-Hübenthal
P
P
Rehbein
A
A
Schlotz
E
E
Pawelec
G
G
D000911:Antibodies, Monoclonal; D018122:B7-1 Antigen / Q000096:biosynthesis*; D018106:CD28 Antigens / Q000096:biosynthesis*; D017252:CD3 Complex / Q000276:immunology; D017635:Clonal Anergy / Q000276:immunology*; D002999:Clone Cells; D006681:HLA-D Antigens / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D016853:Muromonab-CD3; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D018122:B7-1 Antigen; D018106:CD28 Antigens; D017252:CD3 Complex; D006681:HLA-D Antigens; D016853:Muromonab-CD3