The V beta repertoire of mouse gut homodimeric alpha CD8+ intraepithelial T cell receptor alpha/beta + lymphocytes reveals a major extrathymic pathway of T cell differentiation.
Gut intraepithelial lymphocytes (IEL) contain two independent T cell receptor alpha/beta + T cell populations, with different V beta repertoires. In DBA/2 mice (Mlsa, IE+), the CD4+ and heterodimeric alpha/beta CD8+ thymodependent T cell pool shows the same deletion of V beta 6, 8.1, and 11+ cells as found in peripheral lymphoid organs. In contrast, such deletions are not observed in the pool of IEL bearing homodimeric alpha CD8+ chains, in which these V beta families are frequently observed in high amounts. The size of this gut homodimeric alpha CD8+ IEL pool and its different V beta repertoire selection demonstrate the existence of a major extrathymic pathway of T cell differentiation with a gut-restricted localization. The large amount of the thymo-independent, homodimeric alpha CD8+ IEL found in the small bowel may contribute to a first line of defense against exogenous superantigens.
Rocha
B
B
Unités INSERM *U25, UA CNRS 122, Geneva, Switzerland.
Vassalli
P
P
Guy-Grand
D
D
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology; D016827:CD8 Antigens; D002872:Chromosome Deletion; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D016130:Immunophenotyping; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta