Triiodothyronine affects the phytohemagglutinin to concanavalin A proliferative response ratio in sex-linked dwarf chickens.
Euthyroid Cornell K strain and sex-linked dwarf (SLD) strain cockerels (which have abnormally low serum triiodothyronine concentrations) were supplemented with either 0, 0.01, 0.1, or 1.0 ppm of triiodothyronine (T3) in the diet. Peripheral blood lymphocytes (PBL) from these cockerels were obtained by slow-speed centrifugation (slow-spin-prepared PBL). The proliferative response of these PBL to phytohemagglutinin (PHA) and concanavalin A (Con A) was determined when the chicks were 6, 9, and 12 weeks of age. Con A responsiveness was also determined in 12-week-old cockerels using PBL which were separated on Ficoll (Ficoll-prepared PBL). Using slow-spin-prepared PBL, PHA, and Con A responsiveness increased in both strains with increasing levels of T3 supplementation. This enhancing effect of T3 was particularly evident in older cockerels. In 6- and 12-week-old SLD strain cockerels, the PHA:Con A response ratio was significantly (P less than 0.05) lower than in K strain cockerels. At 12 weeks of age the PHA:Con A response ratio of the SLD strain was elevated to K strain control levels by T3 supplementation. Therefore, the lower PHA:Con A response ratio in the SLD strain appears to be partially due to the existing peripheral hypothyroidism in this strain. Using Ficoll-prepared PBL, the effects of T3 on Con A responsiveness differed from those observed when slow-spin-prepared PBL were used. From this study we conclude that T3 supplementation affects mitogen responsiveness and the PHA:Con A response ratio. However, the effects of T3 on mitogen responsiveness depend on the age of the chicken, the level of T3 supplemented, the T cell population stimulated, and the method of lymphocyte enrichment.
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Department of Poultry and Avian Sciences, Cornell University, Ithaca, New York 14853.
Marsh
J A
JA
D000375:Aging; D000818:Animals; D002645:Chickens; D003208:Concanavalin A; D004044:Dietary Proteins / Q000008:administration & dosage; D004306:Dose-Response Relationship, Immunologic; D007037:Hypothyroidism / Q000235:genetics / Q000276:immunology* / Q000503:physiopathology; D007958:Leukocyte Count / Q000187:drug effects; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D009000:Monocytes / Q000187:drug effects; D010835:Phytohemagglutinins; D013601:T-Lymphocytes / Q000145:classification / Q000187:drug effects / Q000276:immunology; D014284:Triiodothyronine / Q000008:administration & dosage*
D004044:Dietary Proteins; D010835:Phytohemagglutinins; D014284:Triiodothyronine; D003208:Concanavalin A