Suppression of chicken J chain production by in ovo bursectomy.

The influence of in ovo bursectomy on the levels of J and mu chains in the sera of embryonic and hatched chicks was studied by the dot blotting immunoassay. The results indicated a decrease in the level of J chains during the embryonic stage after treatment with testosterone compared with normal chicks. Testosterone treatment caused a decrease in J-chain levels after hatching which was more marked in reduced-alkylated than in non-reduced sera. In contrast, testosterone caused no significant change in serum levels of mu chains, either in ovo or after hatching. Our findings further present the paradox that although removal of the bursa of Fabricius by testosterone treatment did not impair mu-chain synthesis, B-cell differentiation was suppressed. These observations indicate that in ovo bursectomy selectively inactivates B-cell differentiation as indicated by the induction of immunodeficiency, and results in the failure of J-chain production.