Helper activity of chicken V beta 1+ and V beta 2+ alpha beta T cells for in vitro IgA antibody synthesis.

Chickens have only two T cell receptor variable beta gene families: V beta 1 and V beta 2 (1). In our previous work we found that IgA production was almost completely suppressed in chickens depleted of V beta 1+ alpha beta T cells by treatment with a TCR V beta 1-specific monoclonal antibody (2), while IgM and IgG production was not affected. Our present results indicate that, in vitro, both V beta 1+ and V beta 2+ chicken cecal tonsil T cells provide help for the differentiation of cecal tonsil IgA B cells, suggesting that the failure of V beta 1+ T cell-depleted chickens to produce IgA is not caused by the inability of V beta 2+ T cells to provide help for IgA production by B cells, but rather by the scarcity of these T cells in mucosal tissues (3), where most IgA responses are induced (4).