MITOGENIC RESPONSES OF THE HEAD-ASSOCIATED LYMPHOID-TISSUES OF THE CHICKEN

A blastogenesis microassay employing 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) was adapted to measure blastogenic responses of lymphocytes from the chicken's head-associated lymphoid t issues (i.e., the harderian gland and conjunctiva-associated lymphoid tissue) to T- and B-cell mitogens. Lymphocytes isolated from periphera l blood, spleen, and the harderian gland had highly significant (P<0.0 1) responses to T- and B-cell mitogens compared with control lymphocyt es cultured without mitogens. Cultured lymphocytes obtained from the h arderian gland had highly significant mitogenic responses to the T-cel l mitogen concanavalin A (25 to 100 mu g/ml) and to the B-cell mitogen Salmonella typhimurium lipopolysaccharide (1.25 to 5.0 mu g/ml) compa red with the control lymphocytes. Mitogenic responses of cultured lymp hocytes obtained from the conjunctiva-associated lymphoid tissue could not be measured within the given parameters of the blastogenesis micr oassay. This was primarily due to the low yield of lymphocytes, which proved to be a limiting factor. The ability of the MTT blastogenesis m icroassay to detect blastogenic responses of the harderian gland to mi togens may be indicative of its usefulness for measuring cell-mediated immunity responses to other antigens.