MDC is a CC chemokine that is produced in B cells, macrophages, monocyte-derived dendritic cells, activated NK cells and CD4 T cells. It signals through the CCR4 receptor. MDC chemoattracts monocytes, dendritic cells and NK cells, and exerts HIV-suppressive activity. The 67 amino acid form of MDC displays reduced chemoattractant activity, but retains HIV-suppressive activity. Recombinant Human MDC is an 8.1 kDa protein containing 69 amino acid residues including the four highly conserved cysteine residues present in the CC chemokines.