TABLE 1.

Classification, structural features, function, and location of the chemokine family members.

Family	Structural features	Function	Location	Chemokines
CXC	The CXC family has a single amino acid residue in between the first two cysteines.	CXC chemokines have the highest ability to attract neutrophils and monocytes.	4q12-13 4q21.21 10q11.1 4q21 5p31 17p13	CXCL1-8 CXCL9-11 CXCL12 CXCL13 CXCL14 CXCL1
CC	The CC chemokine family has the first two cysteine residues adjacent to each other.	CC chemokines are mainly responsible for the recruitment of lymphocytes.	17q11.2 7q11.23 16q13 17q11.2 9q13 2q33-3 9q13 16q13 11q11.2 7q11.23 19p13.2 7q11.23 9q13 5q	CCL1-15 CCL16 CCL17 CCL18 CCL19 CCL20 CCL21 CCL22 CCL23 CCL24 CCL25 CCL26 CCL27 CCL28
C	The C family there is only one cysteine residue and only one disulfide chain.	C chemokine has chemotactic activity for lymphocytes, CD4+ and CD8+ T cells, and NK cells.	1q23	XCL1-2
CX3C	The CX3C chemokine family three amino acid residues separate the first two cysteines.	CX3C chemokines can induce chemotaxis of monocytes and cytotoxic T cells.	16q13	CX3CL1

The spacing of two conserved cysteine residues at the N-terminus determines the nomenclature and classification of the chemokine family members; in CXC, CC, C, and CX3C chemokines. Moreover, according to the classification of chemokines, these four types also have different functions and localizations.