Tumor necrosis factor-alpha in pregnant cattle after intravenous or subcutaneous vaccination with Brucella abortus strain RB51
Palmer, M.V.; Elsasser, T.H.; Cheville, N.F.
American Journal of Veterinary Research 59(2): 153-156
1998
ISSN/ISBN: 0002-9645 PMID: 9492928 Document Number: 484310
Objective-To determine the influence of brucellosis vaccination on tumor necrosis factor-alpha (TNF-alpha) concentrations in pregnant cattle and the possible role of the bovine placenta in TNF-alpha production. Animals-Polled Hereford heifers obtained from a nonvaccinated, brucellosis-free herd and bred at 16 to 27 months at age. All cattle were seronegative for Brucella abortus by results of the standard tube agglutination test. Procedure-At 6 months' gestation, cattle were vaccinated IV with B. 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 solution SC (n = 2). Blood samples were collected periodically for TNF-alpha assays. At necropsy, 8 to 12 weeks after vaccination, placental fluids and fetal blood were collected for TNF-alpha analysis and placental tissues were collected for immunohistochemical detection of TNF-alpha. Results-Radioimmunoassays indicated no increase in TNF-alpha concentration in blood from IV or SC vaccinated cattle, compared with controls. Similarly, TNF-alpha concentrations in amniotic and allantoic fluids from SC vaccinated cattle were not different from values for controls. Although only IV vaccinated cattle developed placentitis, immunohistochemical analysis for TNF-alpha revealed increased immunoreactivity within placental trophoblastic epithelial cells of SC and IV vaccinated cattle. Conclusions-SC vaccination for prevention of brucellosis, using recommended adult dosages, does not result in increase of TNF-alpha concentration in plasma, serum, or placental fluids; however, vaccination of pregnant cattle stimulates trophoblastic epithelial cells to express TNF-alpha, although the physiologic and quantitative importance of this expression remains unknown.