Ultrastructural morphometric analysis of Brucella abortus-infected trophoblasts in experimental placentitis. Bacterial replication occurs in rough endoplasmic reticulum.
Trophoblasts in normal and Brucella abortus-infected caprine placentas were examined by ultrastructural morphometric analysis to establish structural relationships of B abortus with cytoplasmic organelles; brucellae were identified with colloidal gold-labeled anti-B abortus bovine IgG. Cytotrophoblasts had large numbers of B abortus in cisternae of rough endoplasmic reticulum; binucleate trophoblasts did not contain bacteria. In infected trophoblasts there was a significant hypertrophy of B abortus-filled rough endoplasmic reticulum (RER) and a corresponding reduction in normal-appearing RER. Volume and surface density of RER in trophoblasts were: normal placentas (control), 2.8% and 0.30 sq mu; infected placentas, 27.9% (27.4% of which contained B abortus) and 0.56 sq mu (cells containing B abortus) and 3.3% and 0.34 sq mu (cells not containing B abortus). These data suggest that B abortus replicates within the RER of trophoblasts, possibly for synthesis and glycosylation of bacterial membrane proteins.
D000818:Animals; D002003:Brucella abortus; D002006:Brucellosis / Q000473:pathology*; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D005260:Female; D006041:Goats; D008854:Microscopy, Electron; D010922:Placenta Diseases / Q000209:etiology* / Q000473:pathology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000473:pathology*; D014327:Trophoblasts / Q000648:ultrastructure*