Production of transforming growth factor alpha by normal human blood eosinophils.
Transforming growth factor alpha (TGF-alpha) is a pleiotropic factor mediating numerous cellular responses in normal and transformed cells. This includes differentiation, proliferation, migration, and formation of extracellular matrix. TGF-alpha has been demonstrated in circulating eosinophils from the idiopathic hypereosinophilic syndrome and in differentiating promyelocytic leukemia cells in vitro. Whether TGF-alpha production also occurs in normal human blood cells is not known. Northern blot analysis showed that normal human white blood cells consistently expressed the TGF-alpha gene in 47 out of 47 donors. Cell preparations enriched in mononucleated cells, and devoid of granulocytes, showed no TGF-alpha mRNA. In situ hybridization experiments assigned the TGF-alpha gene expression to the eosinophils; 100% of the eosinophils and no other cell types were specifically recognized by the complementary human TGF-alpha riboprobe. White blood cells, incubated at 37 degrees C for up to 6 hours, released immunoreactive TGF-alpha to the incubation medium, as determined by ELISA. In contrast, no TGF-alpha protein was detected in the incubation medium of mononuclear cells. It is concluded that TGF-alpha is constitutively produced and released by normal human blood eosinophils. TGF-alpha provided by eosinophils, may participate in the inflammatory reaction by interacting with mesenchymal and epithelial cells, thus promoting fibrosis or neovascularization.
Walz
T M
TM
Department of Cell Biology, Faculty of Health Sciences, University of Linköping, Sweden.
Nishikawa
B K
BK
Malm
C
C
Wasteson
A
A
D004804:Eosinophils / Q000378:metabolism* / Q000502:physiology; D066246:ErbB Receptors / Q000235:genetics; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D017403:In Situ Hybridization; D007958:Leukocyte Count; D007962:Leukocytes / Q000378:metabolism / Q000502:physiology; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D016211:Transforming Growth Factor alpha / Q000096:biosynthesis* / Q000097:blood* / Q000235:genetics
D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; D012313:RNA; D066246:ErbB Receptors