A cytokine which is a chemoattractant. In laymen's terms, a substance produced by cells in your body to attract other cells to it. First discovered in the study of immunology, but has been extended to other biological phenomena.

The first recognized chemokine was IL-8, which has recently been renamed CXCL8. Now, over 30 chemokines have been identified.

They are detected by cells through chemokine receptors, 18 of which have been identified.

Chemokines are broadly categorized as CC or CXC chemokines, by virtue of the presence of absence of an intervening amino acid between conserved cysteine residues. The receptors can also be categorized by which kind of chemokine they bind and recognize.Of course, there are a few exceptions to this categorization scheme.

Because of the number of chemokines that have been identified by separate groups studying varying biological phenomena, the naming of the chemokines is very convoluted (MIP-1alpha, IP-10, IL-8, eotaxin, etc.), though the receptors themselves have been named in a logical manner (CCR1 through 11, CXCR1 through 6, etc.). The chemokines themselves are being renamed accordingly.