|Foote, Monica - IOWA STATE UNIV., AMES|
|Fowler, M - LAND O'LAKES, MN|
|Miller, B - LAND O'LAKES, IA|
|Beitz, D - IOWA STATE UNIV., AMES|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 2005
Publication Date: August 20, 2005
Citation: Foote, M.R., Nonnecke, B.J., Fowler, M.A., Miller, B.L., Beitz, D.C., Waters, W.R. 2005. Effects of age and nutrition on expression of CD25, CD44, and L-Selectin (CD62L) on T-cells from neonatal calves. Journal of Dairy Science. 88(8):2718-2729. Interpretive Summary: During the first weeks of life, dairy calves experience a heightened susceptibility to a variety of infectious diseases. In tests evaluating the functional capacity of peripheral blood lymphocytes in vitro, cells from 1-wk-old calves were not as responsive as cells from adult cattle. Cells from calves at 8 wk of age, however, were functionally comparable to cells from older cattle, suggesting that specific aspects of the immune system of the calf mature rapidly during the neonatal period. Lymphocytes from calves fed an intensified milk replacer, containing increased amounts of protein and energy, had decreased functional activity when compared to cells from calves fed a standard milk replacer. These results suggest animal maturity and nutrition during the neonatal influence immune function and potentially infectious disease resistance. This information will be very beneficial to the dairy industry worldwide.
Technical Abstract: Effects of the plane of nutrition and age on the proliferation and activation of lymphocyte subsets from milk replacer-fed calves were investigated. Holstein calves were fed a standard (0.45 kg/d of a 20% crude protein, 20% fat milk replacer, n=4) or intensified (1.14 kg/d of a 28% crude protein, 20% fat milk replacer, n=4) diet 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. Relative to the pokeweed mitogen-induced responses of CD4+ cells from steers (5-6 m of age), CD4+ cells from 1-wk old calves showed decreased proliferative activity, delayed increase in CD25 expression and no demonstrable increase in CD44 expression or decrease in CD62L expression. Calf CD8+ and gamma/delta T cell receptor+ cells, unlike T cells from the older animals, did not demonstrate decreased expression of CD62L after stimulation with mitogen. The increased expression of CD44 by mitogen-stimulated gamma/delta T cell receptor+ cells from older animals was not seen in gamma/delta T cell receptor+ cells from 1-wk-old calves. At wk 8 of age, mitogen-induced proliferation and expression of activation antigens by T cells from standard-fed calves were similar to responses of T cells from steers indicating rapid maturation of T cell function during the neonatal period. Feeding calves an intensified milk replacer was associated with decreased proliferation of mitogen-stimulated CD4+, CD8+, and gamma/delta T cell receptor+ cells; decreased CD25 expression by mitogen-stimulated CD4+ and CD8+ cells; and decreased CD44 expression by mitogen-stimulated CD8+ cells. These results indicate that the functional capacity of the calf’s T cell population becomes more adult-like during the first weeks of life and suggest that nutrition modulates T cell function during this period of immune maturation.