A STUDY OF THE SECRETORY IMMUNE SYSTEM OF THE FEMALE GENITAL TRACT

Immune response after vaginal application of antigens in the rhesus monkey

The immune response after vaginal application of antigens was investigated in six sexually mature female rhesus monkeys. Two model antigens, i.e., lipopolysaccharide (LPS) OF Salmonella typhosa and abortive type T-4 coliphages were applied with or without adjuvant. A plastic sponge used as the antigen carrier was introduced into the upper vagina and placed against the ectocervix. For primary immunization, each monkey received 18 vaginal antigen applications and 10 applications for each booster course. For comparison, three other female rhesus monkeys were immunized systemically. Alum or LPS was used as adjuvant. Blood was obtained two times and cervical mucus three times weekly from each monkey. Antibodies were only barely detectable in cervical mucus after the primary vaginal immunization. However, booster treatments resulted in definite antibody responses. Specific antibodies were also detected in the circulating blood after vaginal booster immunization. The antibody level in cervical secretion in three of four cases was higher than that in circulatin blood. Systemic immunization resulted in high levels of circulating antibodies, but less than 10% appeared in cervical secretions. A characteristic decrease in antibody levels in cervical mucus was usually observed at midcycle after local immunization as well as after systemic immunization. More than 90% of T-4 coliphages applied vaginally were absorbed within 48 hours. Although alum appeared to retard the absorption of antigens, it seemed to enhance the local response. More than 90% of the antibodies to the T-4 coliphages could be removed from the serum and cervial mucus by treatment with anti-immunoglobuin G antiserum. The lymphocyte response to antigens was studied by measuring the 3H-thymidine uptake by peripheral blood lymphocytes in culture. A positive response was observed in three of three systemically immunized and in only two of six locally immunized aminals. In general, the immune response was significantly weaker after local vaginal immunization than after systemic immunization.

Secretory antibody response of the cervix to infection with Neisseria gonorrhoeae

Cervical secretions from 157 women were examined for antibody against Neisseria gonorrhoeae by an indirect immunofluorescent antibody test. Antigonococcal antibody was detected in 73 (97%) of 75 infected women, being of the IgG class in 73 (97%), of the IgA class in 71 (95%), and of the IgM class in 29 (39%). IgM antibody was nearly always associated with infections of less than 15 days' duration. Immunoglobulin G, reactive with N. gonorrhoeae, was found in 23 (33%) of 70 non-infected women; of these, 19 had non-gonococcal cervicitis. Neither IgA nor IgM antibodies were detected in these women. Antigonoccal IgA and IgG was found in each of 12 women who had no evidence of infection but were contacts of infected men. Successful treatment resulted in a rapid decline in IgA antibody activity but a more gradual decrease in IgG reactivity.

In vitro study of the possible role of the intrauterine contraceptive device tail in ascending infection of the genital tract

Potentially pathogenic bacteria colonized the mucus coating the tails of both monofilamentous and multifilamentous intrauterine contraceptive devices (IUCD) in 72 (55 per cent) out of 132 in vitro tests. This suggests that the IUCD tail may be responsible for the passage of vaginal bacteria into the uterus.

The local immunological defence system of the human endometrium

The distribution of immunoglobulins and secretory component (SC) in the human endometrium has been studied by an immunoperoxidase technique. SC is present in a proportion of the epithelial cells and the amount of this substance is increased during the secretory phase of the cycle. A variety of immunoglobulins are present, in low concentrations, in the stromal interstitium during the secretory phase of the cycle and these are thought to diffuse passively from the plasma as a non-specific accompaniment of stomal oedema. Only IgA is found in the epithelial cells and this appears solely in those cells containing SC. No immunoglobuln-containing lymphoid cells are present in the endometrium. It is suggested that the endometrium lacks a true local secretory immune system but is able, because of its content of SC, to compensate for this by extracting polymeric IgA from the plasma. This system presumably helps to protect the endometrium against infection but the biological significance of its apparent control by progesterone is uncertain.

Immunoglobulins and secretory component in endometrium and cervix. Influence of inflammation and carcinoma

The synthesis of immunoglobulins and secretory component in the cervix and the endometrium was studied by tissue culture and immunofluorescence. Out of the 75 cervical biopsies studied, 17 were epidermoid carcinomas, 8 were carcinomas in situ and 23 tissues had inflammatory or metaplastic lesions. A total of 49 samples from endometrium were studied, out of which 22 were in the proliferative phase, 17 were in the secretory phase and 4 were carcinomas. In the cervical tissues without lesions, there were very few plasmacytes, the synthesis of immunoglobulins was low and in 66% of the tissues the synthesis of IgG was equal to or higher than that of IgA. With local modifications, the IgG synthesis was even more preponderant and was very important in epidermoid carcinomas which were infiltrated with numerous IgG plasmacytes. Secretory component was synthesized by almost all the tissues except the epidermoid carcinomas. The endometrium did not synthesize immunoglobulins; secretory component was synthesized only by endometrial tissue in the secretory phase and by 2 of the 4 carcinomas studied. It seems that in the cervix and the endometrium there is no relationship between the production of secretory component and the presence of IgA plasmacytes which probably localise as a result of other influences. The conditions in which the local secretory immunological system would react preferentially remain to be determined.

Correlations of sialomucins and IgA in the maternal serum of primiparous and multiparous subjects at delivery

Attention is drawn to correlations between placental coefficients and maternal serum levels of IgA at delivery in primiparae and multiparae. These correlations associate maternal serum IgA with gestational performance and appear to discriminate between groups which differ in that respect. Similar correlations exist between the placental coefficient and maternal serum seromucoid, with group discrimination preserved in primiparae, but not multiparae. Direct correlations between serum seromucoid and IgA in maternal serum can be attributed to their mutual dependence on the size and state of the feto-maternal interface, and may provide a means of detecting placental insufficiency in multigravidae.

Antibiody-facilitated digestion and its implications for infant nutrition

A model of digestion is proposed in which oligopeptides arriving at the small bowel epithelium are bound to secretory antibodies, which hold them in contact with proteases and thus facilitate their breakdown and utilization. "Immunity" and "digestion" are thus seen as two sides of the same coin. Absence of this pathway, predictably, would cause a degree of malabsorption, while partial deficiency (either quantitative or qualitative) would give rise to a coeliac-like illness. Breast-feeding with colostrum and then milk provides the infant gut with both immunity and "digestivity", and this could be adopted therapeutically for coeliac disease and other consequences of local immunodeficiency.

The bacteriology of the cervix and uterus

Fifty hysterectomy specimens were studied by a multiple biopsy technique to determine the normal bacteriological flora of the uterine cavity and cervical canal. All the uterine cavities and 23 of the cervical canals were sterile. The lower half of the other 27 cervical canals contained organisms similar to those found in the vaginal vault.