[Modulation of the humoral immune response in rats by antibodies from the maternal milk]. / Moduliatsiia gumoral'nogo immunnogo otveta u krys antitelami materinskogo moloka.

The influence of specific antibodies of mother's milk on the parameters of humoral immune response and the degree of sensitization to ovalbumin in the progeny was studied in experiments on non-suckling rats. On the second postnatal day lactating rats were immunized subcutaneously with ovalbumin in a dose of 200 micrograms with aluminium hydroxide (10 mg) as adjuvant. On day 22 after birth the young rats which were fed by immunized (test) or intact (control) mothers, received intraperitoneal injections of 100 micrograms ovalbumin. After 8 days the humoral immune response in the young rats was estimated by the number of antibody-forming cells in the spleen, by the count of rosette-forming cells and by the humoral antibody titer. The sensitization degree was evaluated by the titers of reagin antibodies in the passive skin anaphylactic reaction. The number of antibody-forming cells in the spleen of young rats in the test group was 20 times lower as compared to those in the control group. In the test group the humoral antibody titers were suppressed and the sensitization degree was decreased. It has been concluded that the mother's milk antibodies induce immunosuppressive effect on the parameters of the humoral immune response of the progeny and on the degree of their sensitization.

[Specific immunosuppression after peroral administration of antibodies]. / Spetsificheskaia immunosupressiia, obuslovlennaia peroral'nym postupleniem antitel.

The influence of immunization of lactating female rats with sheep red blood cells on the primary immune response of their progeny, and oral administration of heterologous antibodies, on the immune response of suckling rats was studied in experiments on 52 August rats. It was shown that oral antibody administration with breast milk and feeding with heterologous serum resulted in a drastic suppression of the splenic antibody-producing cells and in a fall of the humoral antibody titre in the suckling rats. The immunosuppression was reversible and could not be adoptively transferred. It is concluded that the antibodies entering the newborns' body with the mother's milk not only provide the passive immunity but also produce a regulatory effect on the immune system.