Characterization of interleukin-13 receptor in carcinoma cell lines and human blood cells and comparison with the interleukin-4 receptor.
The interleukin-13 receptor is characterized by ligand-binding and crosslinking studies and compared with the interleukin-4 receptor. Crosslinking of radio-labeled hIL-4 and hIL-13 to the receptors on human carcinoma and mast cell lines demonstrated a predominant subunit at 130 kDa with two other minor bands of lower molecular mass (75 kDa and 65 kDa) in autoradiography. All binding of 125I-IL-13 was specifically blocked when the carcinoma cell suspensions were incubated with an excess of unlabeled hIL-4. However, unlabeled hIL-13 was unable to completely displace 125I-hIL-4 from the 130 kDa protein. In addition, 125I-hIL-13 showed no binding to mouse fibroblast cells transfected with human 130 kDa hIL-4 receptor c-DNA. Using weighted nonlinear computer modeling of the data from several equilibrium binding studies with human mast cells, a model of two binding sites for IL-4 (Kd = 50 and 190 pmol/L) and one site for IL-13 (Kd = 100 pmol/L) fitted better than a one site model with a very high level of significance (F = 10.66, P < 0.0001). It can be concluded that human IL-4R and hIL-13R are similar but distinct. This conclusion is supported here for the first time by a strong statistical criterion.
Feng
N
N
Institute of Clinical Chemistry, University Hospital Zürich.
Schnyder
B
B
Vonderschmitt
D J
DJ
Ryffel
B
B
Lutz
R A
RA
D015703:Antigens, CD / Q000032:analysis*; D006801:Humans; D018793:Interleukin-13 / Q000378:metabolism; D053661:Interleukin-13 Receptor alpha1 Subunit; D015847:Interleukin-4 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000737:chemistry; D008970:Molecular Weight; D018123:Receptors, Interleukin / Q000032:analysis*; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; C508181:IL13RA1 protein, human; C508183:Il13ra1 protein, mouse; D018793:Interleukin-13; D053661:Interleukin-13 Receptor alpha1 Subunit; D018123:Receptors, Interleukin; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4; D015847:Interleukin-4