Studies on antilymphocyte antibody in the chicken. II. Effect of rabbit antithymus and antibursa globulin on immune reactions in young chickens.

Four-week-old chickens repeatedly injected intraperitoneally with heterologous antithymus globulin (ATG) and antibursa globulin (ABG) were immunized, in the course of treatment, with bovine γ-globulin (BGG). The ATG and ABG depressed the production of anti-BGG antibody. On the other hand, only ATG was effective in suppressing experimental allergic encephalomyelitis. Immunoelectrophoretic analysis of sera from chickens treated with ATG, ABG and NRG (normal rabbit globulin) revealed that those globulins are themselves immunogenic. ATG and ABG induced in the spleen a moderate depletion of lymphocytes and plasma cells respectively. These reagents produced lymphocytopenia and granulocytopenia, but a similar, although less expressed, effect on leucocytes in the peripheral blood could be induced by NRG. Thymus, bursa, caecal tonsil, Peyer's patches and lymphoid masses of the intestine were not influenced by ATG, ABG and NRG. The results are discussed and interpreted as further evidence for the delineation between immune functions of the thymus and the bursa of Fabricius in the chicken.