The expressions of co-stimulatory molecules are altered on putative antigen-presenting cells in cord blood

The aim of our study was to estimate the expressions of both B7-H1 and B7-H4 as well as CD200 and CD200R co-stimulatory molecules on immature myeloid and lymphoid dendritic cells, B CD19(+) lymphocytes and monocytes in umbilical cord blood of healthy neonates and in peripheral blood of healthy adults.

Thirty-nine healthy full-term neonates from physiological single pregnancies and 27 healthy adults were included in the study. The expressions of B7-H1, B7-H4, CD200, CD200R antigens were estimated using flow cytometry. Statistical analysis was performed using a non-parametric Mann-Whitney U-test and parametric Wilcoxon's test.

The expressions of B7-H1 and B7-H4 molecules on immature BDCA-1(+) myeloid dendritic cells were significantly lower in umbilical cord blood of healthy neonates when compared with those cells in peripheral blood of healthy adults (P < 0.0001). Furthermore, the suppression of B7-H4 molecule on BDCA-2(+) lymphoid dendritic cells was observed in cord blood of healthy neonates when compared with peripheral blood of healthy adults (P < 0.02). The expressions of CD200 antigen on BDCA-1(+) cells, CD200R antigen on BDCA-2(+) cells and CD200R antigen on B CD19(+) cells were significantly lower in cord blood of healthy neonates. On the other hand, the expressions of CD200 and CD200R as well as B7-H4 co-stimulatory molecules on CD14(+) cells were significantly higher in cord blood when compared with peripheral blood.

The increased percentages of CD14(+) monocytes with the expressions of CD200 and CD200R as well as B7-H4 co-stimulatory molecules can suggest the increased immunomodulatory properties of neonatal monocytes in cord blood.