Dual function of human necrosis factor receptor 75 in cytotoxicity induced by human tumor necrosis factor alpha.
OBJECTIVE
To study the function of human TNF receptor-75 (hTR75) and the interaction between human TNF receptor-55 (hTR55) and hTR75 in hTNFalpha-induced cytotoxicity.


METHODS
HEp-2 cells were transfected with bicistronic expression vector of hTR75 gene, and HEp-2-A75 cells with intrinsic hTR55 and overexpressed hTR75 were obtained. Two hTNFalpha muteins with exclusive specificity for hTR55 or hTR75 were constructed, expressed in high-levels in E coli, and then purified. hTNFalpha-induced cytotoxicity was determined by crystal violet colorimetric method.


RESULTS
The expression of hTR75 in HEp-2 cells was demonstrated by RT-PCR and indirect ELISA, and was quantified by binding of [125I]hTNFalpha and Scatchard analysis. The overexpressed hTR75 could markedly increase the susceptibility of HEp-2 cells to hTNFalpha.


CONCLUSIONS
hTR75 could not only partially mediate hTNFalpha-induced cytotoxicity independently but also fulfill an accessory role in enhancing or synergizing hTR55-mediated cytotoxicity. It played a dual function in hTNFalpha-induced cytotoxicity in HEp-2 cells.
Fang
J
J
Shanghai Research Center of Biotechnology, Chinese Academy of Sciences, Shanghai 200233, China.
Lu
F
F
Chen
C Q
CQ
D015703:Antigens, CD / Q000235:genetics / Q000502:physiology*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D004357:Drug Synergism; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007822:Laryngeal Neoplasms / Q000378:metabolism / Q000473:pathology; D009154:Mutation; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000502:physiology*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D015398:Signal Transduction; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000494:pharmacology*
D015703:Antigens, CD; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha