engleski

Effect of the androgen analogue mibolerone on migration and maturation of bursal cells in chickens

Background and Purpose: Until chickens achieve full imunocometence at several weeks of age, they are more susceptible to infection. Because it has been proposed that mibolerone causes precocious maturation and migration of B cells from the bursa of Fabricius, mibolerone was evaluated as a candidate for provoking enhanced humoral immune responses to sheep red blood cells and killed Brucella abortus in young chicks. Material and Methods: (a) Immune responses were analysed after giving 1 or 10 &micro ; g mibolerone one the 16th day of embryonation or 0.1 mg/ml in drinking water during the post-hatch period. (b) To assess mibolerone’ s effect on precursor B cells, bursae from 11-day-old embryos were transplanted onto chorioallantoic membranes of age-matched embryos whose bursal development had been prevented by treatment with 2.5 &micro ; g mibolerone on the 5th day of embryonation. (c) To assess migration of B cells to peripheral organs, eighteen-day-old embryos were treated with mibolerone, killed 3 days later and their spleen cells assayed for number of surface Ig-positive (sIg+) cells. Results: (a) Chickens treated when embryos with 10 &micro ; g had transient bursal atrophy whereas 1&micro ; g had no effect. Bursae of chickens treated with mibolerone in drinking water regressed prematurely and were completely atrophic by 3 to 4 weeks of age. Mibolerone administered in either manner had no adverse effect on immune responses, but it did not enhance them. (b) Transplanted bursae were populated by host precursor B cells that formed lymphoid follicles. (d) The number of sIg+ cells was significantly greater in treated than in untreated embryos. Conclusions: It is concluded that mibolerone casued rapid migration of bursal lymphocytes from bursae to peripheral lymphoid organs but it did not case rapid maturation of B cells.

chicken; B cells; mibolerone; maturation; immune response

nije evidentirano