Identification, cloning, and characterization of a novel soluble receptor that binds IL-22 and neutralizes its activity.
With the use of a partial sequence of the human genome, we identified a gene encoding a novel soluble receptor belonging to the class II cytokine receptor family. This gene is positioned on chromosome 6 in the vicinity of the IFNGR1 gene in a head-to-tail orientation. The gene consists of six exons and encodes a 231-aa protein with a 21-aa leader sequence. The secreted mature protein demonstrates 34% amino acid identity to the extracellular domain of the IL-22R1 chain. Cross-linking experiments demonstrate that the protein binds IL-22 and prevents binding of IL-22 to the functional cell surface IL-22R complex, which consists of two subunits, the IL-22R1 and the IL-10R2c chains. Moreover, this soluble receptor, designated IL-22-binding protein (BP), is capable of neutralizing IL-22 activity. In the presence of the IL-22BP, IL-22 is unable to induce Stat activation in IL-22-responsive human lung carcinoma A549 cells. IL-22BP also blocked induction of the suppressors of cytokine signaling-3 (SOCS-3) gene expression by IL-22 in HepG2 cells. To further evaluate IL-22BP action, we used hamster cells expressing a modified IL-22R complex consisting of the intact IL-10R2c and the chimeric IL-22R1/gammaR1 receptor in which the IL-22R1 intracellular domain was replaced with the IFN-gammaR1 intracellular domain. In these cells, IL-22 activates biological activities specific for IFN-gamma, such as up-regulation of MHC class I Ag expression. The addition of IL-22BP neutralizes the ability of IL-22 to induce Stat activation and MHC class I Ag expression in these cells. Thus, the soluble receptor designated IL-22BP inhibits IL-22 activity by binding IL-22 and blocking its interaction with the cell surface IL-22R complex.
Kotenko
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SV
Department of Molecular Genetics and Microbiology, University of Medicine and Dentistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA. kotenkse@umdnj.edu
Izotova
L S
LS
Mirochnitchenko
O V
OV
Esterova
E
E
Dickensheets
H
H
Donnelly
R P
RP
Pestka
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive / Q000276:immunology; D016466:CHO Cells; D019556:COS Cells; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000302:isolation & purification; D006801:Humans; D007378:Interleukins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D008024:Ligands; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface; D018123:Receptors, Interleukin; D012995:Solubility; D014407:Tumor Cells, Cultured; D000097043:Interleukin-22
D002352:Carrier Proteins; D018076:DNA, Complementary; D007378:Interleukins; D008024:Ligands; D011956:Receptors, Cell Surface; D018123:Receptors, Interleukin; D000097043:Interleukin-22; C433253:IL22RA2 protein, human; C415369:interleukin-22 receptor