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Chickens were treated intracoelomically with extracts of chicken thymus (TE) and bursa of Fabricius (BE), the former known to be enriched with avian thymic hormone. Doses of 1.0 mg TE enhanced blastogenic responses of peripheral blood lymphocytes to phytohemagglutinin (PHA) and concanavalin A for at least 3 wk after cessation of treatment. Very high doses(More)
The chicken thymus-specific antigen (T1) was localized within certain cell types of the thymus using an indirect immunofluorescent (FA) test. One of the cell types was similar to small mononuclear cells, whereas the other was much larger and irregular in shape and probably of the recticuloepithelial type. The small cells occurred in clumps mostly at the(More)
In order to determine if mibolerone causes rapid development of the humoral immune system as previously hypothesized, 12-day-old chicken embryos were injected with 0.1, 1, or 10 micrograms mibolerone. Mibolerone caused bursal atrophy in a dose-dependent manner with severe atrophy at the 10 micrograms dose, substantial atrophy at the 1 microgram dose, and(More)
Carrageenans (CGN), sulphated polygalactans, have been reported to be cytotoxic for macrophages in vitro. On this basis, the effect of the 3 major CGN types on humoral immune responses in chickens was investigated. Carrageenan had no effect on body and lymphoid organ weights. Histologically, CGN produced a significant proliferation of reticuloendothelial(More)
Steroids have significant influences on the immune system of birds and mammals, and the Food and Drug Administration should consider them in the regulatory review process. As discussed here, androgens have different effects depending on dose and the timing of administration. If given in sufficient amount during the critical time of bursal development,(More)
The effects of various doses of mibolerone, an analog of testosterone, in the development of the bursa of Fabricius and the humoral immune system were examined by injecting 0.01, 0.1, 1, 10 or 100 micrograms mibolerone into the chorio-allantoic cavity of 12-day-old chick embryos. Treatment with 0.01 or 0.1 micrograms of mibolerone caused slight or no bursal(More)
Mitogenic responsiveness of peripheral blood lymphocytes (PBL) of chickens was suppressed by either pretreatment with or addition to the culture medium of various concentrations of carrageenan (CGN). Pretreatment for 1 hr significantly suppressed response to Concanavalin A (Con A) and Pokeweed mitogen (PWM) but did not affect Phytohemagglutinin (PHA)(More)