Molecular characterization and functional analysis of murine interleukin 4 receptor allotypes.
The murine interleukin 4 receptor (IL-4R) exists as a transmembrane protein transducing pleiotropic IL-4 functions, or as soluble (s)IL-4-binding molecule with potent immunoregulatory effects. In this study we identified and characterized a murine IL-4R allotype. Sequence analysis of the IL-4R cDNA of BALB/c mice revealed 18 base substitutions leading to three extracellular and five cytoplasmic amino acid changes when compared with the published IL-4R sequence of C57BL/6 mice. Analyses with allotype-specific mAbs revealed that AKR/J and SJL/J mice possess the newly identified BALB/c IL-4R allotype whereas the IL-4Rs of C3H, CBA, DBA-2, and FVB/N mice are identical to that of the C57BL/6 mouse. The extracellular Thr49 to Ile substitution abrogates one N-glycosylation site in the naturally occurring BALB/c IL-4R as well as in the experimentally point mutated C57BL/6-T49I sIL-4R, and both molecules display a nearly threefold reduction in IL-4-neutralizing activity compared to the C57BL/6 sIL-4R. In line with this, a significantly enhanced dissociation rate of IL-4 was detected for the BALB/c IL-4R allotype by surface plasmon resonance and in radioligand binding studies with IL-4R-transfected cell lines. These findings suggest that the altered ligand binding behavior of the newly described IL-4R allotype may influence the IL-4 responsiveness, thus contributing to the diverse phenotypes of inbred mouse strains in IL-4-dependent diseases.
Schulte
T
T
Institute of Clinical Microbiology and Immunology, University of Erlangen-Nürnberg, 91054 Erlangen, Germany.
Kurrle
R
R
Röllinghoff
M
M
Gessner
A
A
D000483:Alleles; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D000918:Antibody Specificity / Q000235:genetics; D001483:Base Sequence; D001666:Binding Sites, Antibody / Q000235:genetics; D002462:Cell Membrane / Q000378:metabolism; D004262:DNA Restriction Enzymes; D018604:Epitope Mapping; D005110:Extracellular Space / Q000737:chemistry / Q000276:immunology; D005260:Female; D006031:Glycosylation; D007700:Kinetics; D051379:Mice; D008806:Mice, Inbred AKR; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D016513:Mice, SCID; D019948:Receptors, Interleukin-4 / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D019948:Receptors, Interleukin-4; D004262:DNA Restriction Enzymes