MIP-1 alpha is a beta family (CC) chemokine and has been designated CCL3. MIP-1 alpha and MIP-1 beta, two closely related but distinct proteins, were originally purified from medium conditioned by a LPS-stimulated murine macrophage cell line. Cotton rat MIP-1 alpha cDNA encodes a 92 amino acid (aa) residue precursor protein with a 23 aa putative signal peptide. Mature cotton rat MIP-1 alpha shares approximately 70% amino acid identity with human MIP-1 alpha. MIP-1 alpha is expressed in a wide variety of cells, including lymphocytes, fibroblasts, and epithelial cells, as well as monocytes/macrophages.
MIP-1 alpha has been shown to play an important role in the recruitment of mononuclear cells. Additionally, MIP-1 alpha has been reported to have chemoattractant and adhesive effects on lymphocytes, preferentially promoting the chemotaxis of Th1 cells. MIP-1 alpha has also been shown to attract B cells, eosinophils, and dendritic cells. In addition, MIP-1 alpha augments cytolytic activity of NK cells (1). MIP-1 alpha has been identified as a stem cell inhibitory factor that can inhibit the proliferation of hematopoietic stem cells in vitro as well as in vivo. It has been demonstrated that MIP-1 alpha can bind the chemokine receptors CCR1 and CCR5 (2).
