Degradation of human 125I-interferon alpha by isolated perfused rabbit kidney and liver.

Cells attached to intrauterine devices (IUDs) release interferon (IFN) in the medium during incubation in vitro. Most of the IFN is released during the first hour suggesting that the cells had been previously induced and were probably already producing IFN in vivo. Characterization of the IFN indicates that most of it is of gamma-type with a trace of alpha. Production of IFN in the uterine fluid would represent a first example of the physiological IFN response and may serve to modulate some of the mechanisms preventing implantation of blastocyst. The actual presence of IFN in the uterine secretion remains to be demonstrated. PIP: IUDs were removed under aseptic conditions from 16 women at the 5th-6th day of the menstrual cycle after having been in situ for periods of 20-26 months. After removal, the tails of the devices were eliminated and cells attached to the IUDs were treated and analyzed. About 78% of the cells were macrophages, 19% neutrophils, 3% lymphocytes. The highest amount of interferon (IFN) was received from the medium during the 1st 80 minutes of incubation. There is a maximum increase in the kinetic of IFN release during the 1st hour followed by a slow progressive increase for the next 24 hours when it tends to level off. Antiviral activity was considerably acid-labile, insensitive to antihuman IFN-beta serum, slighly sensitive to antihuman IFN-alpha serum, and markedly sensitive to antihuman IFN-gamma serum. This indicates that cells attached to IUDs can produce IFN-gamma and probably a little IFN-alpha. The antiviral activity of IFN may also be useful in preventing spread of opportunistic viruses, and fungus infections in the endometrium. The presence of IFN in the uterine fluid may help modulate several mechanisms preventing implantations of the blastocyst.