IL-8 is a proinflammatory CXC chemokine that can signmal through the CXCR1 and CXCR2 receptors. It is secreted by monocytes and endothelial cells. IL-8 chemoattracts and activates neutrophils. Recombinant IL-8 (endothelial-derived) is a 8.9 kDa protein containing 77 amino acid residues.