Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/12/1996
Publication Date: N/A
Technical Abstract: Brucella abortus strain RB51 is a new subcutaneous brucellosis vaccine for cattle. Intravenous infection of cattle with strain RB51 results in placentitis but no abortions. To characterize the alteration in trophoblastic cell glycoconjugate production during infection, lectin histochemistry was performed on formalin-fixed cotyledonnary placenta from pregnant cattle following intravenous infection with strain RB51. DBA, an alpha-linked N-acetylgalactosamine-specific lectin, reacted specifically with the cytoplasm of binucleated trophoblastic cells which produce placenta lactogen during gestation. All strain RB51-infected cotyledonnary placenta from full term cattle had marked diffuse depletion of DBA positive binucleated trophoblastic cells. Double immunostaining of cotyledons for strain RB51 antigens and DBA did not demonstrate a correlation between number of infected trophoblasts and decreased labeling with DBA. Labeling of trophoblastic cells for programmed cell death (TUNEL technique) did not demonstrate differences between normal and infected cotyledons. We hypothesize that decreased DBA labeling may have occurred either from decreased cellular glycoconjugate production due to inflammatory products, or from decrease production of new binucleated cells with exhaustion of older cells. These hypothesis's are currently being tested by labeling the trophoblastic cells with a proliferation marker (PCNA), and studying the ultra structural morphology of the binucleated trophoblastic cells by transmission electron microscopy.