Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 12, 1996
Publication Date: N/A
Technical Abstract: Intravenous inoculation of SRB51 has been shown to cause placentitis fetal infection in pregnant cattle. To determine the safety of s.c vaccination of pregnant cattle, Polled Hereford heifers were vaccinated at 6 months of gestation with 10(9) CFU SRB51, 3 x 10(8) CFU S19 or saline. Signs of abortion, or lesions consistent with brucellosis not seen in either vaccine group. At full term, 2/5 SRB51-vaccinates had SRB51 in superficial cervical lymph nodes in the region of vaccination. SRB51 or S19 were not recovered from other tissues or fluids from heifers or their calves. SRB51-vaccinates did not develop antibody titers detected by standard tube agglutination, but did develop titers greater (P<0.05) than S19-vaccinates on a dot ELISA for anti-SRB51 antibodies. In blastogenesis assays, PBMC showed proliferation to irradiated SRB51 and S19 in SRB51- and S19-vaccinates which were greater (P<0.05) than that seen in controls. Cells from superficial cervical lymph nodes of S-19- vaccinates but not SRB51-vaccinates, demonstrated greater proliferation in response to irradiated SRB51 or S19 than cells from controls. These results suggest that pregnant cattle can be safely vaccinated with SRB51, inducing humoral and cell-mediated immunity without widespread infection, placentitis and abortion.