Effect of uterine immunization and oestradiol on specific IgA and IgG antibodies in uterine, vaginal and salivary secretions.

Levels of IgA and IgG antibodies were measured in uterine and vaginal secretions to examine the effect of uterine immunization on the genital tract humoral immune system. When ovariectomized animals were immunized on Day 0 and boosted 13 days later by placing sheep erythrocytes (SRBC) directly in the uterine lumen (UT/UT) immunization), a pronounced IgA and IgG antibody response was detected in uterine secretions measured on Day 26. This response was 20-30-fold greater than that measured following Peyer's patch immunization and boosting (PP/PP) and Peyer's patch immunization followed by uterine boosting (PP/UT). In contrast to uterine antibody responses that were oestradiol-dependent following PP/PP and PP/UT immunization, UT/UT immunization resulted in IgA and IgG antibody responses that were hormonally independent. To determine whether immunological information is distributed beyond the immediate site of immunization, ovariectomized rats were immunized and boosted by injection of SRBC into one uterine horn. When uterine secretions from the contralateral (non-immune) horns were analysed, IgA and IgG antibodies were found in uterine secretions after oestradiol stimulation. IgA and IgG antibodies were also present in vaginal secretions following UT/UT immunization and ligation of uteri at the utero-cervical junction. This response was hormonally dependent in that vaginal antibody levels were lowered by oestradiol treatment. IgG but not IgA antibodies were also found in saliva of UT/UT immunized animals. Oestradiol had no effect on salivary IgG levels in contrast to those of the genital tract. In summary, these experiments indicate that immunization of uteri can elicit pronounced IgA and IgG antibody responses in uterine secretions and this response is not altered by oestradiol. Moreover, immunization at one site in the genital tract results in the appearance of antibodies at other uterine sites (the contralateral-non-immunized horn), in vaginal secretions, in serum and at other mucosal sites, such as the salivary glands.