T-CELLS EXPRESSING THE V-BETA-1 T-CELL RECEPTOR ARE REQUIRED FOR IGA PRODUCTION IN THE CHICKEN

While alpha-beta-T cells in mammals may express one of many variable (V) gene families in the beta-locus, chickens have only two V(beta) gene families. The avian V(beta)2+ T cells are recognized by the T-cell receptor 3 (TCR3) monoclonal antibody and V(beta)1+ T cells are recognized by the TCR2 antibody, which we used to selectively suppress development of V(beta)1+ T cells in order to examine their functional role. Suppression was accomplished by multiple injections of anti-TCR2 antibodies beginning in embryonic life and perpetuated by thymectomy 8 days after hatching. Young birds thus depleted of V(beta)1+ T cells had greater than normal numbers of V(beta)2+ T cells and appeared as healthy as thymectomized and untreated controls. While production of IgM and IgG antibodies was unimpaired, IgA antibody production was severely compromised in the V(beta)1-depleted birds. The levels of secretory IgA in bile and lung lavage fluid were reduced 1000- to 10,000-fold and secretory IgA antibodies were not produced in response to mucosal immunization. B-cell production of IgA antibodies thus appears to require T cells expressing the V(beta)1 genes, whereas T cells that express the V(beta)2 genes lack this capacity.