[Update on a titration method for measuring the interferon-producing capacity in humans]

To make it possible to measure the interferon-alpha (IFN-alpha) producing capacity in a great number of healthy donors and patients, we developed the simple method (the whole blood method). For the measurement of the IFN-producing capacity, the heparinized blood was incubated with Sendai virus at 37 degrees C for 20 hours. The IFN activity of the culture supernatants was determined by the cytopathic effect inhibition assay. We measured the IFN-producing capacity in 531 healthy donors and 130 cancer patients. The results showed that the IFN-producing capacity in cancer patients was significantly lower than that in healthy donors. Although there were individual variations in the IFN-producing capacity, no age and sex differences were observed. These results indicate that this method is useful for the measurement of IFN-producing capacity in human.