Expression and secretion of murine IL-12 and murine IL-28B in vitro. (A) Western blotting for murine IL-12p40 and murine IL-28 proteins from HEK 293T cell lysates 48 hours after transfection. Mock-transfected cells received empty pVAX vector. (B) ELISAs show secretion of the active IL-12 p35/p40 heterodimer as well as the IL-28 protein into the supernatants of transfected cells.