Chemokines
15.8.1 Chemokines
Chemokines comprise a family of about 40 low-molecular-weight cytokines (see 15.8.4, Cytokines) with important roles in the immune system, as well as functions beyond it.1-5 The name chemokine, a contraction of “chemotactic cytokine,” reflects the common property, by which chemokines were originally identified, of promoting leukocyte chemotaxis.
Chemokines are classified into 4 subfamilies, based on their cysteine (C) residues and other amino-acid (X) residues (see 15.6.1, Genetics, Nucleic Acids and Amino Acids):
CXC |
1 amino-acid residue between the 2 N-terminal cysteines |
CC |
N-terminal cysteines adjacent |
XC |
cysteines 1 and 3 not present |
CX3C |
3 amino acids between the cysteine residues |
Examples of specific chemokines, by subfamily, are shown below:
Subfamily Name |
Synonym |
Examples5 |
Receptors | |
|---|---|---|---|---|
Systematic Name |
Common Names and Abbreviation |
|||
CXC |
α class |
CXCL1 |
growth-related oncogene α (GRO-α), melanoma growth stimulatory activity protein (MGSA) |
CXCR2 |
CXCL4 |
platelet factor 4 (see 15.7, Hemostasis) |
|||
CXCL5 |
epithelial cell-derived neutrophil attractant 78 (ENA-78) |
CXCR2 |
||
CXCL6 |
granulocyte chemoattractant protein 2 (GCP-2) |
CXCR1, CXCR2 |
||
CXCL8 |
interleukin 8 (IL-8) (see 15.8.4, Cytokines) |
CXCR1, CXCR2 |
||
CXCL14 |
chemokine isolated from breast and kidney tissue (BRAK), bolekine |
|||
CC |
β class |
CCL1 |
inducible 309 (I-309) |
CCR8 |
CCL3 |
macrophage inflammatory protein 1a or 1α (MIP-1α) |
CCR1, CCR5 |
||
CCL5 |
regulated on activation of normal T cells expressed and secreted (RANTES) |
CCR1, CCR3, CCR5 (also called CD195; see 15.8.2, CD Cell Markers) |
||
CCL7 |
monocyte chemoattractant (or chemo-tactic) protein 3 (MCP-3) |
CCR1, CCR2, CCR3 |
||
CCL21 |
secondary lymphoid tissue chemokine (SLC), chemokine β-9 (CKβ-9), exodus 2, 6Ckine |
CCR7 (also called CDw107; see 15.8.2, CD Cell Markers) |
||
XC |
γ class |
XCL1 |
lymphotactin, activation-induced, T-cell-derived, and chemokine-related (ATAC), single cysteine motif 1α (SCM-1α) |
XCR1 |
XCL2 |
SCM-1β |
XCR1 |
||
CX3C |
δ class |
CX3CL1 |
fractalkine |
CX3CR1 |
Expanded common names of the chemokines are often unwieldy and uninformative and so are rarely used, though use of the abbreviations persists. Terms such as those in the tabulation above for chemokine, chemokine subfamily, and chemokine receptor do not need to be expanded, but context should provided at first mention, eg:
the CXC chemokine family
the chemokine CXCL1
chemokine receptor CXCR2
A useful reference on chemokines is the Cytokine Family Database (dbCFC): http://cytokine.medic.kumamoto-u.ac.jp.6