Cartoon illustrating the finding that MCs in term placental villi are major sites of BAFF and APRIL ligand synthesis and that both vCTB cells and MCs may receive BAFF/APRIL signals. BAFF and APRIL may target in an autocrine manner to three receptors, BAFF-R, TACI, and BCMA, on MC and in a paracrine manner to two receptors, BAFF-R and BCMA, on vCTB cells.