Autoantibodies to zona pellucida in tubectomized women

The study was conducted to detect autoantibodies to zona pellucida by indirect immunofluorescence technique. A total of 60 human sera was examined, which included 15 tubectomized, 15 pregnant, 15 nonpregnant fertile women, and 15 fertile men. In the unabsorbed sera, anti-zona activity was observed in 53.3% of the tubectomized women and in 40.0% of the nonpregnant fertile women, 20.0% of the pregnant women and 26.7% of the fertile men. All the positive sera were then absorbed with porcine red blood cells and retested to exclude the false positive reaction due to nonspecific serum components. After absorption, immunological response was retained in 26.7% of the tubectomized women and lost in all the other women and men. The positive sera were further absorbed with zona-coated eggs and were retested. Fluorescence was lost in all the positive sera. This observation demonstrates the presence of antibodies, specific to zona antigens, in tubectomized women. To date, however, antibodies to zona antigen have not been demonstrated in the tubectomized women. Presence of anti-zona activity in tubectomized women may be an autoimmune response, possibly due to absorption and degradation of the ova into the peritoneal cavity or in the reproductive tract and the subsequent exposure of the degradation products to the immune system