MIP-3 is a CC chemokine that signals through the CCR1 receptor. MIP-3 chemoattracts monocytes, resting T-lymphocytes and neutrophils, but does not chemoattract activated lymphocytes. Additionally, MIP-3 has been shown to inhibit colony formation of bone marrow myeloid immature progenitors. Recombinant human MIP-3 is an 11.3 kDa protein containing 99 amino acid residues, including the four highly conserved cysteine residues present in CC chemokines.