Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/2005
Publication Date: 7/25/2005
Citation: Foote, M., Nonnecke, B.J., Fowler, M., Miller, B., Beitz, D.C., Waters, W.R. 2005. Effects of age and nutrition on proliferation and activation of mitogen stimulated T cell subsets from neonatal calves [abstract]. 2005 Annual Meeting American Dairy Science Association-American Society of Animal Science-Canadian Society for Animal Science. p. 45. Interpretive Summary:
Technical Abstract: Effects of nutrition and age on mitogen-induced (i.e. in vitro) proliferation and activation of lymphocyte subsets from milk replacer-fed calves were investigated. Calves were fed standard (0.45 kg/d of a 20% crude protein, 20% fat milk replacer, n = 4) or intensified (1.04 kg/d of 28% crude protein, 20% fat milk replacer, n = 4) diets from 1 to 8 wk of age. Average daily weight-gain of intensified-diet (0.66 kg/d) calves was greater than standard-diet (0.27 kg/d) calves. When compared to responses of pokeweed mitogen-stimulated CD4 cells from juvenile steers (5-6 m of age), CD4 cells from 1-wk old calves displayed decreased proliferation, delayed CD25 expression and no increase in CD44 expression or decrease in CD62L expression in response to mitogenic stimulation. The mitogen-induced decrease in CD62L expression by steer CD8 and gamma/delta T cells was not seen in stimulated CD8 and gamma/delta T cell populations from 1-wk old calves. Similarly, the mitogen-induced increase in CD44 expression by adult gamma/delta T cells was not observed in stimulated gamma/delta T cell populations from 1-wk old calves. At 8-wk of age, however, mitogen-induced responses (i.e. proliferation and expression of activation markers) by T cells from standard-fed calves were comparable to responses of cells from juvenile steers. Feeding an intensified diet was associated with decreased proliferation of CD4, CD8, and gamma/delta T cells; decreased CD25 expression on stimulated CD4 and CD8 cells; and decreased CD 44 expression on stimulated CD8 cells. These results indicate that the functional capacity of the calf's T cell population mature rapidly during the first weeks of life and suggest that nutrition influences maturation of T cell function during this critical period.