The effect of thymulin on avian IL-2 receptor expression.
The effect of thymulin on IL-2 receptor (IL-2R) expression by avian splenocytes was examined in the functionally hypothyroid sex-linked dwarf (SLD) and in normal euthyroid K strain chickens. Daily thymulin injections of 0, 0.05 and 5.0 ng/100 g body weight were given from hatching until 4 weeks of age. ConA-treated and non-stimulated splenocytes from these animals were analyzed by flow cytometry for their expression of IL-2Ralpha, CD4 and CD8 cell surface molecules. ConA activation increased the number of IL-2R+ cells within K strain more than in the SLD. Thymulin treatment increased the number of IL-2R+ cells in the SLD but had the opposite effect in K strain chickens. Mitogen activation or thymulin treatment had little effect on the IL-2R density within small cell populations. In contrast, mitogen activation increased the density of IL-2R on larger cell populations in both K and SLD. IL-2R densities on non-stimulated larger cells decreased in the SLD after thymulin exposure. Thymulin treatment produced no effect on the mean IL-2R densities for large activated cells. ConA stimulation increased the number of CD4+ cells in both strains. The density of CD4 expression was modulated by both mitogen activation and thymulin treatment. ConA stimulation produced an increase in the number of CD8+ cells. The SLD had fewer CD8+ cells than did the K strain and thymulin treatment had little effect on this population in either strain. Mitogen stimulation increased the density of CD8 on CD8+ cells but again thymulin treatment had little effect. These results suggest that thymulin can modulate IL-2R expression on splenocytes and that this effect may be dependent upon the thyroidal status of the animal. Further, these data suggest that thymulin has a differential effect on the CD4 and CD8 T-cell subpopulations.
Chandratilleke
D
D
Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, C5-103 VMC, Ithaca, NY14853, USA.
Marsh
J A
JA
D000818:Animals; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D002645:Chickens; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D013935:Thymic Factor, Circulating / Q000494:pharmacology*; D014284:Triiodothyronine / Q000494:pharmacology
D015704:CD4 Antigens; D016827:CD8 Antigens; D015375:Receptors, Interleukin-2; D014284:Triiodothyronine; D013935:Thymic Factor, Circulating