The critical region in the cytoplasmic domain of human IL-4 receptor for induction of IgE synthesis.
To examine the region critical for differentiation in the human IL-4 receptor (hIL-4R), we transfected the Abelson murine leukemia virus (A-MuLV)-transformed murine pre-B cell line A20 with plasmid DNA encoding the hIL-4R. Transfectants expressed high affinity hIL-4Rs on the cell surface. Treatment with LPS and hIL-4 induced germline C epsilon transcripts in hIL-4R expressing A20 cells. Several hIL-4R mutant plasmids were then transfected into A20 cells and the transfectants were examined for hIL-4R expression and the ability to induce germline C epsilon transcripts upon stimulation with LPS and hIL-4. Although all A20 transfectants tested expressed the high-affinity hIL-4R, A20 transfectants expressing the mutant hIL-4R, which contains only 8 amino acids in the cytoplasmic domain, did not respond to LPS and hIL-4 with germline C epsilon transcripts. In addition, A20 transfectants expressing an internally deleted hIL-4R, in which the deleted region has been identified as the critical region for growth signal transduction in the previous study, failed to induce germline C epsilon transcripts with LPS and hIL-4. These results indicate that the critical region for the differentiation signal in the hIL-4R is identical to that for the growth signal, suggesting that IL-4 may share, at least partly, a common signal pathway for both growth and differentiation.
Schultz
C
C
Department of Immunology, DNAX Research Institute, Palo Alto, CA 94304-1104, USA.
Izuhara
K
K
Coffman
R
R
Harada
N
N
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D002461:Cell Line, Transformed; D003593:Cytoplasm / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D017578:Immunoglobulin Class Switching; D007073:Immunoglobulin E / Q000096:biosynthesis* / Q000235:genetics; D015847:Interleukin-4 / Q000378:metabolism*; D051379:Mice; D018123:Receptors, Interleukin / Q000235:genetics / Q000276:immunology*; D019948:Receptors, Interleukin-4; D017384:Sequence Deletion; D015398:Signal Transduction; D014158:Transcription, Genetic; D014162:Transfection
D015703:Antigens, CD; D018123:Receptors, Interleukin; D019948:Receptors, Interleukin-4; D015847:Interleukin-4; D007073:Immunoglobulin E