A human monocytic cell line, THP-1-S, was cultured in a serum-free medium. The effect of the culture supernatant of THP-1-S on the cytotoxicity of rTNF-α to three kinds of cell lines and the binding of rTNF to its receptor were tested. The supernatant inhibited the cytotoxicity of rTNF-α when tested by the neutral red uptake method. In addition, the supernatant blocked the binding of 125I-rTNF-α to its receptor. Furthermore, following precipitation with PEG we detected complexes between rTNF-α and the inhibitory factor which formed during incubation with the culture supernatant from THP-1-S cells. However, the supernatant did not bind to or down-regulate the receptor for TNF-α on the cell surface of L-M-2d6 cells. This factor eluted with an apparent molecular mass of 63,000 Da by gel filtration and did not react with antibodies against p55 and p75 TNF receptors. These data suggest that human monocytic cells are capable of releasing an inhibitory factor against rTNF-α in serum-free culture conditions.
|Number of pages||7|
|Journal||MICROBIOLOGY and IMMUNOLOGY|
|Publication status||Published - 1999 Jan 1|
- THP-1 cell
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