B7 family molecules are favorably positioned at the XXXX maternal-fetal interface.

@entity1 @entity4634 @entity2937 @entity7938 @entity72650 @entity379
The @entity1 placenta utilizes both active and passive mechanisms to evade rejection by the maternal immune system. We investigated the pattern of expression of the B7 family of immunomodulatory molecules @entity4634 ( @entity4634 ), @entity2937 ( @entity2937 ), and @entity7938 ( @entity7938 ) at the term maternal-fetal interface. Northern blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses showed that @entity4634 mRNA is abundant in term placenta and that cytotrophoblasts are sources of this message. Immunohistochemistry demonstrated that @entity4634 is constitutively expressed by the syncytiotrophoblast and by extravillous cytotrophoblasts, both of which are juxtaposed to maternal blood and tissue. By contrast, placental stromal cells, including macrophages, lacked the protein. Expression of @entity4634 protein was low in first-trimester placenta compared to second- and third-trimester tissue (P < 0.05) and was enhanced in cultured cytotrophoblasts by treatment with either @entity379 or epidermal growth factor (P < 0.05), suggesting that one or both of these mediators regulates @entity4634 expression in the placenta. RT-PCR and immunofluorescence analysis of term placental tissue revealed different patterns of expression of the immunostimulatory protein, @entity2937 . In contrast to @entity72650 mRNA and protein were absent in cytotrophoblast cells but present in maternal macrophages and some fetal macrophages. The @entity7938 mRNA and protein were absent at the maternal-fetal interface. These studies document expression of the B7 family proteins at the maternal-fetal interface and demonstrate that @entity4634 is positioned such that it could facilitate protection of fetal cells against activated maternal leukocytes. Conversely, @entity2937 was absent on trophoblasts and was appropriately localized to fetal and maternal macrophages, which may participate in antigen presentation.
