Distribution of viral antigen in uterus, placenta and foetus of cattle persistently infected with bovine virus diarrhoea virus

The tissue distribution and cellular localisation of bovine virus diarrhoea virus (BVDV) was investigated in the uterus, placentomes, intercotyledonar y foetal membranes and foetal organs of three persistently infected (PI) pr egnant heifers. The uterus and ovaries of a non-pregnant PI heifer were als o included in the study. Cryostat sections were examined using immunohistoc hemical techniques and monoclonal antibodies against BVDV. A double immunof luorescence technique was used to identify BVDV positive cells that also sh owed staining for either the leukocyte common antigen CD45 or the cytoskele tal filament vimentin, BVDV antigen was detected in all the organs examined , and was present in both epithelial and non-epithelial cells. In all organ s many of the virus-positive cells also showed reactivity for vimentin, In the foetal liver and spleen a small, scattered population of virus-positive cells showed reactivity for CD45. A few cells showed reactivity both for B VDV antigen and for CD45 in the placentomes and intercotyledonary foetal me mbranes. In contrast to earlier reports, only scattered cells in the foetal part of the placentomes, the cotyledons, showed reactivity for BVDV antige n. However, in the chorion of the intercotyledonary foetal membranes, a lar ger proportion of the trophoblast cells showed reactivity for BVDV, especia lly the binuclear trophoblast cells. In the uterus, pregnancy appeared to f avour virus replication, as the sections from the pregnant heifers showed m uch stronger staining and a higher proportion of viral antigen-positive cel ls than sections from the non-pregnant PI heifer. (C) 1999 Elsevier Science B.V, All rights reserved.