Complex binding of leukemia inhibitory factor to its membrane-expressed and soluble receptors.

The complex interaction of leukemia inhibitory factor (LIF) with its specific receptor present on the cell surface, in isolated membranes and in solution, has been examined in detail. Several aspects of this complexity have been highlighted, including the presence of high- and low-affinity murine LIF receptors, biphasic dissociation of human LIF from apparently homogeneous high- or low-affinity human LIF receptors, and unusual species cross-reactivity. The unusual species cross-reactivity observed between murine and human LIF has also been exploited to map an important receptor binding epitope on human LIF.