Differential association of protein tyrosine kinases with the T cell receptor is linked to the induction of anergy and its prevention by B7 family-mediated costimulation.
When stimulated through their antigen receptor, without costimulation, T cells enter a state of antigen-specific unresponsiveness, termed anergy. B7-mediated costimulation, signaling via CD28, is sufficient to prevent the induction of anergy. Here we show that ligation of T cell receptor (TCR) by alloantigen alone, which results in anergy, activates tyrosine phosphorylation of TCR zeta and its association with fyn. In contrast, TCR ligation in the presence of B7 costimulation, which results in productive immunity, activates tyrosine phosphorylation of TCR zeta and CD3 chains, which associate with activated lck and zeta-associated protein (ZAP) 70. Under these conditions, CD28 associates with activated lck and TCR zeta. These data suggest that the induction of anergy is an active signaling process characterized by the association of TCR zeta and fyn. In addition, CD28-mediated costimulation may prevent the induction of anergy by facilitating the effective association of TCR zeta and CD3 epsilon with the critical protein tyrosine kinase lck, and the subsequent recruitment of ZAP-70. Strategies to inhibit or activate TCR-associated, specific protein tyrosine kinase-mediated pathways may provide a basis for drug development with potential applications in the fields of transplantation, autoimmunity, and tumor immunity.
Boussiotis
V A
VA
Division of Hematologic Malignancies, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
Barber
D L
DL
Lee
B J
BJ
Gribben
J G
JG
Freeman
G J
GJ
Nadler
L M
LM
D016475:3T3 Cells; D000818:Animals; D018122:B7-1 Antigen / Q000502:physiology*; D017252:CD3 Complex / Q000378:metabolism; D017635:Clonal Anergy; D002999:Clone Cells; D004789:Enzyme Activation; D006801:Humans; D007519:Isoantigens / Q000276:immunology; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D019000:Phosphotyrosine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D014162:Transfection; D051746:ZAP-70 Protein-Tyrosine Kinase
D018122:B7-1 Antigen; D017252:CD3 Complex; D007519:Isoantigens; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases; C494957:FYN protein, human; C494960:Fyn protein, mouse; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051076:Proto-Oncogene Proteins c-fyn; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; C497262:Zap70 protein, mouse