Tolerant CD8 T cells induced by multiple injections of peptide antigen show impaired TCR signaling and altered proliferative responses in vitro and in vivo.
The mechanisms responsible for peripheral CD8 T cell tolerance to foreign Ags remain poorly understood. In this study we have characterized the state of CD8 T cell tolerance induced in F5 TCR transgenic mice by multiple peptide injections in vivo. The tolerant state of CD8 T cells is characterized by impaired proliferative responses, increased sensitivity to cell death, and failure to acquire cytotoxic effector function after in vitro antigenic challenge. In vivo monitoring of CD8 T cell proliferation using 5-carboxyfluorescein diacetate succinimidyl ester showed that a large subset of the tolerant T cell population failed to divide in response to peptide. TCR down-regulation could not account for this loss of responsiveness to Ag since recombination-activating gene-1 (RAG-1)-/-F5 CD8 T cell responses were similar to those of RAG-1(-/-)F5 x RAG-1(-/-)F1 T lymphocytes, which express lower levels of the transgenic TCR. Analysis of early signal transduction in tolerant CD8 T cells revealed high basal levels of cytoplasmic calcium as well as impaired calcium mobilization and tyrosine phosphorylation after cross-linking of CD3epsilon and CD8alpha. Together these data indicate that repeated exposure to soluble antigenic peptide in vivo can induce a state of functional tolerance characterized by defective TCR signaling, impaired proliferation, and increased sensitivity to cell death.
Dubois
P M
PM
Immunologie Cellulaire, Laboratoire de Biologie Moléculaire et Cellulaire, Ecole Normale Supérieure de Lyon Centre National de la Recherche Scientifique, France. patrice.dubois@ens-lyon.fr
Pihlgren
M
M
Tomkowiak
M
M
Van Mechelen
M
M
Marvel
J
J
D000818:Animals; D000956:Antigens, Viral / Q000008:administration & dosage / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016923:Cell Death / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology; D007108:Immune Tolerance / Q000235:genetics; D007274:Injections, Intraperitoneal; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010446:Peptide Fragments / Q000008:administration & dosage / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D019076:Transgenes / Q000276:immunology; D014758:Viral Core Proteins / Q000008:administration & dosage / Q000276:immunology*
D000956:Antigens, Viral; D018984:Epitopes, T-Lymphocyte; D010446:Peptide Fragments; D016693:Receptors, Antigen, T-Cell, alpha-beta; D014758:Viral Core Proteins; C102366:nucleoprotein (366-374), influenza virus