Submitted to: International Virtual Conference on Infectious Diseases of Animals
Publication Type: Abstract Only
Publication Acceptance Date: 5/2/1997
Publication Date: N/A
Technical Abstract: TNF-alpha is a key cytokine in inflammatory processes and mediates many of the clinical signs associated with endotoxemia due to gram negative bacterial infection. In order to determine the influence of brucellosis vaccination on TNF-alpha levels in pregnant cattle and the possible role of the placenta in TNF-alpha production, pregnant cattle were vaccinated IV with Brucella abortus strain RB51 (n=10), SC with B. abortus strain RB51 (n=5), or SC with B. abortus strain 19 (n=5); controls received pyrogen free saline SC (n=2). Radioimmunoassays showed no elevations in TNF-alpha levels in serum or plasma from IV or SC vaccinated cattle that differed from controls (P>0.05). Similarly, TNF-alpha levels in amniotic and allantoic fluids from SC vaccinated cattle were not different from controls (P>0.05). Immunohistochemistry for TNF-alpha revealed increased immunoreactivity within trophoblastic epithelial cells in SC and IV vaccinated cattle. Immunoreactivity was most extensive in IV vaccinated cattle that developed vaccine induced placentitis. These studies indicate that SC vaccination for the prevention of brucellosis using recommended adult dosages does not result in elevations of TNF-alpha in plasma, serum or placental fluids; however, vaccination of pregnant cattle does stimulate trophoblastic epithelial cells to express TNF-alpha even when placentitis is not histologically evident.