Systemic IgA Antibody Responses against Bovine Serum Albumin in the Chicken

Chickens intravenously immunized with bovine serum albumin (BSA) responded against the antigen with the production of IgA anti-BSA antibodies in their sera. An immunological memory was observed. The secondary responses were characterized by a two-peak pattern. The antigen injection into the intestinal lumen hardly produced the IgA antibodies in the serum. The optimal antigen dose for IgA antibody production was 50mg per kg of body weights. The youngest chicken which was able to elicit IgA antibody production in the serum was virtually 14-day-old. Each of spleen and Peyer's patch cells from chickens primed with the antigen and unprimed evoked adoptive IgA antibody responses of various levels on the antigenic stimulus in recipient chickens bursectomized and X-irradiated. Spleen cells from unprimed chickens gave rise to good IgA antibody responses in recipients thymectomized and X-irradiated. Bursectomy or thymectomy at the ages of various days suppressed the IgA antibody responses in different degrees. Earlier the bursa of Fabricius or the thymus was removed, the greater was the rate of the suppression