Decreased surface expression of B7–1, B7–2, and CD40, cognate B-cell ligands for T-cell interaction, in term and preterm cord blood–derived B cells and dendritic cells compared with adult cells. Monocytes were purified from PBMCs and differentiated into dendritic cells as described in “Generation of monocyte-derived dendritric cells.” Data are shown as mean (± SEM) of 10 independent experiments using 10 independent adult (AB), cord (CB), or preterm cord (PreCB) blood samples with each assay performed in triplicate for cord blood–derived B cells (A) and dendritic cells (B). Statistically significant differences are shown. *P < .001; **P ≤ .005.