Abstract
HIRAI, N., HATTORI, N., GEORGIADES, J., OSTHER, K. and BERG, K. A Cytotoxic Substance (CTS-51) Produced by Human Buffy Coat Cultures Stimulated by Staphylococcal Enterotoxin B: Further Characterization and Combined Action with Interferon. Tohoku J. exp. Med., 1986, 148 (1), 87-97 - A recently recognized unique cytotoxic substance, CTS-51, was tested for the heat or acid stability, trypsin digestion and dialysis. Moreover, influences of elevated incubation temperatures or serum concentrations of medium on the cytotoxic activity of CTS-51, and the combination effects of CTS-51 and human leucocyte interferon (HuIFN-α (Le)) were investigated. The cytotoxic activity of CTS-51, which is promoted by a small molecule easily passable the dialysis membrane, was found to be very stable to heat (even at 100°C for 30min) or acid (pH 2.0 for 24hr at 4°C) treatments. The treatment with 0.75% trypsin for 1hr did not diminish the CTS-51 activity. The susceptibility of Daudi lymphoma cells to the antiproliferative action of HuIFN-α (Le) was further potentiated by treating the cells with CTS-51 for 16hr. On the other hand, the CTS-51 activity which was revealed to be prescribed by its concentration in the medium, was not potentiated at 39°C when compared to that at 37°C in contrast to HuIFN-α (Le) action, and was reduced according to the increase of the fetal calf serum concentration in the medium.
