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Keywords:

  • Autoimmunity;
  • neonatal tolerance;
  • male accessory glands;
  • maternal immunoregulation

ABSTRACT: Adult female rats were immunized with 5 mg or 25 mg of modified rat male accessory glands (MRAG) incorporated to complete Freund's adjuvant (CFA) before, during, and after pregnancy. The mothers and litters were exchanged between the experimental and normal groups. The offspring were brought up to 20 days of age and immunized with 5 mg of MRAG-CFA and 5 mg of human serum albumin (HSA)-CFA. Anti-MRAG antibodies were detected in the offspring brought up by the immunized mothers and the titers were similar to those of the foster mothers whereas in the offspring of the experimental group fostered by normal mothers antibodies to MRAG were not detected. The DTH performed in the offspring 13 days after the immunization was significantly diminished in male and female offspring from the 5 mg and 25 mg experimental group fostered by normal mothers (P<0.0005 for all groups). Similar results were found when the offspring from normal mothers were suckled by mothers immunized with MRAG-CFA.

To assess whether MRAG or HSA administered to female rats reached the offspring via the placenta or the milk, female rats were immunized with 3 mg of 125I-MRAG-CFA or with 3 mg of 125I-HSA-CFA. When radioactivity was measured in neonates (n=ll) that were suckled by the 125I-MRAG-CFA immunized mothers, the specific activity was 116 in stomach (0.4 μg of MRAG) and 940 in the total organs (3.8 μg of MRAG). In the litters that were killed before suckling (n= 18) had started, the radioactivity was not observed in stomach and was lower in the total organs. The radioactivity found in the offspring of 125I-HSA-CFA immunized mothers was similar for both the suckling and the non-suckling pups. We can conclude that there is an immunoregulation of the immune response to self-antigens through the placenta and the milk.