Brief report Macrophage inflammatory protein-1a uses a novel receptor for primitive hemopoietic cell inhibition

Macrophage inflammatory protein-1a (MIP-1a) is a member of the chemokine family of proinflammatory mediators. In addition to its inflammatory roles, MIP-1a has been shown to be active as an inhibitor of primitive hemopoietic cell proliferation. Indeed, a dysfunction in this inhibitory process has been postulated to contribute to leukemogenesis. Research has been aimed at characterizing the receptor involved in cellular inhibition by MIP-1a. This study demonstrates that of all the b-chemokines tested, only MIP-1a is capable of inhibiting primitive hemopoietic cell proliferation. Because no MIP-1a– specific receptors have been identified, this suggests that inhibition is mediated by an uncharacterized receptor. Further evidence for the involvement of a novel receptor in this process is the equivalent potencies of MIP-1aS and MIP-1aP variants of human MIP-1a and the fact that primitive cells from bone marrow derived from individual MIP-1a receptor null mice display a full response to MIP-1a inhibition. (Blood. 2001;98:3476-3478)