Proliferation response of transfected Ba/F3 cell line upon stimulation with OSM, IL-31 and OSMR-L-GPL. Ba/F3 cells stably transfected with OSM and IL-31 receptor components were cultured in triplicates with 2-fold dilutions of purified OSMR-L-GPL, or an equivalent volume of PBS, and fixed amounts of OSM (8 ρm) or IL-31 (80 ρm). After a 48-h culture period, a [3H]thymidine pulse was carried out for 4 h, and the amount of incorporated radioactivity was determined.