IL-13 enhances CD40 expression on PB B cells. Cells were cultured for 3 days in medium (thin line) or with IL-4 (thick line) or IL-13 (dotted line), and cells were stained with the anti-CD40 MoAb G28-5 (lower panel) or an irrelevant isotype-matched control MoAb against CD34 (upper panel). The results are from one representative experiment of three.