Cloning and functional characterization of a novel human CC chemokine that binds to the CCR3 receptor and activates human eosinophils.
Eotaxin has been found to bind exclusively to a single chemokine receptor, CCR3. Using expression sequence tag screening of an activated monocyte library, a second chemokine has been identified; it was expressed and purified from a Drosophila cell culture system and appears to only activate CCR3. Eotaxin-2, MPIF-2, or CKbeta-6, is a human CC chemokine with low amino acid sequence identity to other chemokines. Eotaxin-2 promotes chemotaxis and Ca2+ mobilization in human eosinophils but not in neutrophils or monocytes. Cross-desensitization calcium mobilization experiments using purified eosinophils indicate that eotaxin and MCP-4, but not RANTES, MIP-1alpha, or MCP-3, can completely cross-desensitize the calcium response to eotaxin-2 on these cells, indicating that eotaxin-2 shares the same receptor used by eotaxin and MCP-4. Eotaxin-2 was the most potent eosinophil chemoattractant of all the chemokines tested. Eotaxin-2 also displaced 125I-eotaxin bound to the cloned CCR3 stably expressed in CHO cells (CHO-CCR3) and to freshly isolated human eosinophils with affinities similar to eotaxin and MCP-4. 125I-Eotaxin-2 binds with high affinity to eosinophils and both eotaxin and cold eotaxin-2 displace the ligand with equal affinity. Eotaxin and eotaxin-2 promote a Ca2+ transient in RBL-2H3 cells stably transfected with CCR3 (RBL-2H3-CCR3) and both ligands cross-desensitized the response of the other but not the response to LTD4. The data indicate that eotaxin-2 is a potent eosinophil chemotactic chemokine exerting its activity solely through the CCR3 receptor.
White
J R
JR
Department of Biopharmaceutical Sciences, SmithKline Beecham, King of Prussia, Pennsylvania 19406, USA.
Imburgia
C
C
Dul
E
E
Appelbaum
E
E
O'Donnell
K
K
O'Shannessy
D J
DJ
Brawner
M
M
Fornwald
J
J
Adamou
J
J
Elshourbagy
N A
NA
Kaiser
K
K
Foley
J J
JJ
Schmidt
D B
DB
Johanson
K
K
Macphee
C
C
Moores
K
K
McNulty
D
D
Scott
G F
GF
Schleimer
R P
RP
Sarau
H M
HM
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D016466:CHO Cells / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D054413:Chemokine CCL11; D054423:Chemokine CCL24; D054412:Chemokine CCL8; D018925:Chemokines / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D019742:Chemokines, CC; D003001:Cloning, Molecular; D006224:Cricetinae; D016207:Cytokines / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004804:Eosinophils / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D018945:Monocyte Chemoattractant Proteins / Q000235:genetics; D051381:Rats; D054397:Receptors, CCR3; D019707:Receptors, Chemokine / Q000378:metabolism* / Q000502:physiology
C515456:CCL11 protein, human; C515484:CCL24 protein, human; C515453:CCL8 protein, human; C515350:CCR3 protein, human; C515458:Ccl11 protein, rat; C515352:Ccr3 protein, rat; D054413:Chemokine CCL11; D054423:Chemokine CCL24; D054412:Chemokine CCL8; D018925:Chemokines; D019742:Chemokines, CC; D016207:Cytokines; D018076:DNA, Complementary; D018945:Monocyte Chemoattractant Proteins; D054397:Receptors, CCR3; D019707:Receptors, Chemokine; D002118:Calcium