Submitted to: International Virtual Conference on Infectious Diseases of Animals
Publication Type: Abstract Only
Publication Acceptance Date: April 20, 1997
Publication Date: N/A
Technical Abstract: To further characterize the effects of corticosteroid-induced stress on the immune system of dairy cattle, functional and phenotypic characteristics of blood MNL populations from control and dexamethasone-treated (0.04 mg/kg per d for three consecutive days) Holstein bulls were evaluated concurrently. In vivo administration of dexamethasone caused a >97% reduction in in vitro secretion of IFN-gamma by mitogen-stimulated MNL by day 2 after the first treatment. In vitro secretion of IgM was reduced by >50% on days 2 and 3 after the first treatment, but returned to normal sooner than IFN-gamma secretion. Concurrent with changes in the secretion of these immunologically relevant proteins were changes in the mean fluorescence intensities (indicator of expression per cell) of major histocompatibility (MHC) class I and II antigens and the WC1 antigen, and the proportion (%) of B cells, CD3+ T cells, gamma/delta T cells, and the MHC class II+ cells in the MNL population.