IL-7 inhibits both basal and BMP2-stimulated bone formation in neonatal calvarial organ cultures in vitro. Neonatal calvaria (2 days old) were cultured for 2 weeks in the presence or absence of IL-7 (50 ng/ml) and/or BMP2 (50 ng/ml). Calvaria were stained with hematoxylin and eosin and photographed at ×100 magnification. Dark pink bands indicate old bone, while light pink bands represent newly formed bone. Data are representative of two independent experiments.