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In the bovine synepitheliochorial placenta key sites of fetal-maternal interaction are placentomes consisting of maternal caruncles interdigitating with fetal cotyledons. The aim of this study was to establish an epithelial cell line from caruncles of pregnant cows and to develop a model to study restricted trophoblast invasion, pathogenesis of pregnancy associated diseases and pathways of infection and transport. Primary epithelial cells were isolated, successfully subcultured for 32 passages and cryopreserved at various stages. The cultures were termed bovine caruncular epithelial cell line-1 (BCEC-1). Cytokeratin, zonula occludens-1 protein and vimentin but neither alpha-smooth muscle actin nor desmin were detected by immunofluorescence performed every 5 (+/-1) passages. These results were confirmed by Western blotting. BCEC-1 were then cultured either without matrix or on fibronectin or collagen coated Transwell polyester membrane inserts, respectively, enabling separate access to the basal or apical epithelial compartments. Transmission and scanning electron microscopy of BCEC-1 revealed ultrastructural features also observed in vivo, such as apical microvilli and junctional complexes. Transepithelial electrical resistance (TEER) was measured regularly and revealed an increase with advancing confluence in all cultures. Cultures on coated inserts reached confluence and corresponding TEER-levels at an earlier stage. In addition, the cells were tested negative for bovine virus diarrhoea (BVD) virus, but were permissive for the virus. In conclusion, the BCEC-1 cell line retained characteristics of maternal caruncular epithelial cells as observed in vivo and in primary cell cultures and thus will be a highly useful tool for future studies of pathways of invasion, fetal-maternal communication, transport and infection.

The present study was undertaken to establish reference values for the composition of blood leucocyte populations in neonatal calves by differential leucocyte cnunts and immunophenotyping. Neonatal calves 1 h post parturn @.p.) wcrc found to have a vcry high absolute number of granulocytes whde the number of peripheral blood mononuclear cclls was lower than in calves aged 3-9 weeks. The relative numbers of T cell subpopulations were similar in newborn and older calves, but newborn calves had lower percentages of B cells and MtIC class I1 posltive cells. Within the first 4 h of life the relauve numbers of CD2', CD6', and CD8' 1' cells dcclincd in colostrum-fed as well as in colostrum-deprived calves. In contrast, the percentage o f M H C class I1 positive cells and monocytes increased from 1 h to 4 h p.p. particularly in colostrum-fed calvcs. Although there is some evidence for immatunty o f lymphocytes in neonatal calves, the immune system of these animals seems to be fully present at birth.