PROLIFERATIVE RESPONSES AND BINDING-PROPERTIES OF HEMATOPOIETIC-CELLSTRANSFECTED WITH LOW-AFFINITY RECEPTORS FOR LEUKEMIA INHIBITORY FACTOR, ONCOSTATIN-M, AND CILIARY NEUROTROPHIC FACTOR

Specific low-affinity receptors for leukemia inhibitory factor (LIF), oncostatin M (OSM; gp130), and ciliary neurotrophic factor (CNTF; rece ptor alpha, CNTFRalpha) may be utilized in various combinations to gen erate high-affinity binding sites and signal transduction. We have tes ted the ability of combinations of these receptors to transduce a prol iferative signal in BAF-B03 cells. Coexpression of the LIF receptor an d gp130 in these cells conferred high-affinity LIF and OSM binding and responsiveness to LIF and OSM. These cells also responded to CNTF in the absence of detectable binding. The further addition of CNTFRalpha conferred high-affinity CNTF binding and enhanced responsiveness to CN TF but did not modify responses to LIF or OSM. Coexpression of LIF rec eptor and CNTFRalpha resulted in a nonfunctional high-affinity binding site. These data are consistent with a role for the CNTFRalpha in enh ancing CNTF action but the CNTFRalpha is not absolutely required for C NTF action and suggest a wider range of targets for CNTF.