Submitted to: Journal of Interferon and Cytokine Research
Publication Type: Abstract Only
Publication Acceptance Date: 10/6/2002
Publication Date: 11/1/2002
Citation: EICHER, S.D., MCMUNN, K.A., HAMMON, H.M., DONKIN, S.S. TOLL-LIKE RECEPTORS AND ACUTE PHASE CYTOKINE GENE EXPRESSION IN DEXAMETHASONE AND GROWTH HORMONE TREATED CALVES. JOURNAL INTERFERON CYTOKINE RESEARCH. 2002. P. 22S-182.
Technical Abstract: Toll-like receptors (TLR) are pattern recognition molecules that direct cellular activation by microbial antigens. The activation of TLR lead to acute phase cytokine expression and the initiation of an appropriate immune response. To determine changes in toll-like receptors and acute phase cytokines in cattle following treatment with dexamethasone (a synthetic adrenocortical steroid) and growth hormone, 28 calves were given the control (Cnt), dexamethasone (DEX), growth hormone (GH), or dexamethasone and growth hormone (DXGH) treatments for 8 wk. Blood was collected on wk 2, 4, 6, and 8. Calves were exsanguinated at 8 wk, a lung lavage was performed and spleen and thymus tissues collected. RNA was extracted from blood leukocytes, lung lavage cells, spleen and thymus cells and quantified for expression of Interleukin-1 (IL-1), IL-1 receptor antagonist (IL-1Ra), tumor necrosis factor (TNF), TLR 2, and TLR 4. Blood leukocytes had treatment, time, and treatment by time effects only for expression of IL-1 Ra (P<.01). IL-1 expression of lung lavage cells was greatest for calves on the DXGH treatment compared to the other treatments (P<.05), however IL-1 Ra was not different among the treatments. Lavage cell TLR 2 expression was enhanced (P<.05) with DXGH compared to either DEX or GH, but TLR 4 did not differ among treatments. TNF expression of lavage cells was enhanced (P<.05) by DXGH compared to the other treatments. Spleen cell TNF expression was enhanced by the DEX treatment alone compared to the GH treatment (P<.05), but no other gene expression of spleen cells was changed by the treatments. Thymus cells were not different among treatments in expression of any of the genes. These data show that TLR 2 and acute phase cytokine expression can be changed by stress and growth hormones in vivo, which may thus alter resistance of animals to disease.