Effects of human placental lactogen on the expression of CD163 and CD14 on human monocytes in culture

The effect of human placental lactogen (hPL), a member of the somatomammotrophin family, on the regulation of the scavenger receptor molecules CD14 and CD163 on human monocytes cultured for 48 h was investigated. Cells were cultured in the presence or absence of the hormone and also in the presence or absence of IFN-gamma and dexamethasone. Monocytes cultured in the presence of hPL showed a significant increase in the expression of CD14 in both males and females compared to background. When IFN-gamma and dexamethasone were added to the cultures, CD14 expression was decreased and was not rescued by the presence of hPL. hPL alone had no effect on the expression of CD163 on cultured monocytes from either gender, although cells cultured in the presence of IFN-gamma and dexamethasone showed a profound increase in their expression of CD163. This expression was augmented further by the presence of hPL in the cultures over a 48-h period. These results support the hypothesis of a potential role of this hormone in the regulation of the innate immune response.