Intracellular Localization of Brucella abortus in Bovine Placenta

Invasion of the gravid bovine uterus by Brucella abortus often leads to placentitis and abortion. Within the placenta, brucellae replicate to high numbers in the trophoblastic ep-ithelium. 1.7.8 Minimal degenerative changes in brucellae-filled trophoblasts suggest a unique bacterium-host cell relation-ship. In experimentally infected goats * and in chick embryo^,^ B. abortus replicates in the rough endoplasmic reticulum (RER) of trophoblasts and in nonphagocytic cells, respec-tively. Localization in the RER is unique among bacterial pathogens and may be critical for replication of B. abortus in certain tissues and in the pathogenesis of bovine brucel-losis. Before this host-parasite relationship is further inves-tigated, it is necessary to determine if B. abortus replicates in the RER of trophoblasts in the natural host. In this study, we report the intracellular location of B. abortus in the gravi