ARS | Publication request: ADMINISTRATION OF DEXAMETHASONE (DXM) TO DAIRY BULLS INHIBITS INTERFERON- GAMMA (IFN-GAMMA) AND POLYCLONAL IGM SECRETION BY POKEWEED MITOGEN (PWM)- STIMULATED MONONUCLEAR LEUKOCYTES (MNL) IN VITRO

Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 1995
Publication Date: N/A

Technical Abstract: Eight dairy bulls were used; 4 were injected intramuscularly with DXM on 3 consecutive days, and 4 served as controls. Blood was collected at -5, -4, and -3 days before the first injection (day 0), and at 2, 3, 4, 5, 9, 10, and 11 days after the first injection. Administration of DXM inhibited (P <0.001) the capacity of PWM-stimulated peripheral blood MNL to secrete IFN-gamma and IgM on day 2 and 3 after the first injection. The capacity to secrete IgM returned to normal more quickly than the capacity to secrete IFN-gamma. IFN-gamma secretion in vitro was positively correlated (P <0.01) with the % CD2+, CD3+, CD8+, and gamma/delta T-cells in blood. Percent of MHC Class I and II antigen+ cells was negatively correlated (P <0.001). Mean fluorescence intensity (MFI) of the latter markers was positively correlated (P <0.001) with IFN-gamma secretion. IgM secretion was positively correlated (P <0.01) with the % B-cells; CD3+, CD4+, and gamma/delta T-cells; and MFI of MHC Class I and II antigens. IgM secretion was negatively correlated (P <0.001) with % MHC Class II+ cells. These observations suggest that DXM inhibits broad aspects of bovine T/B-cell physiology.