Local immunological response in the vagina, cervix and endometrium

Abstract

The mechanism of the local excretion of secretory IgA (SIgA) in exocrine secretions has been reviewed. Numerous local IgA-plasma cells, in the lamina propria of the glandular mucosa, synthesize dimeric IgA with J-chain. Free secretory component (FSC) is synthesized and accumulated in the Golgi area of the columnar epithelial cells. It is then supposed to get onto their cell membranes. Dimeric IgA (and some IgM) reaches tn dimeric IgA (and some IgM) and the FSC located in the cell-membrane, whereby SIgA is formed. The complex becomes mobilized and is transported toward the apical part of the cell, where it will be excreted into the mucous coat covering the epithelium. In the female genital tract, the cervical mucosa appears to be better adapted to achieve a local secretory immune system. The endometrium seems less suitable, being normally short of local plasma cells. The vaginal wall appears almost incompatible with the proposed mechanism of local antibody secretion. Criteria for establishing a local immune response in the female genital tract comprise: 1) a lack of correlation between antibody titers in secretions and serum; 2) the demonstration that the secretory antibodies are mainly of IgA class and 3) that they are SIgA molecules, possessing bound secretory component. However, the best criterion would be 4) the observation that antibody is actually synthesized in samples of mucosa, by in vitro culture or immunohistology. Reviewing the literature, relatively few examples were found where SIgA antibodies were demonstrated, and unambiguous evidence for their local synthesis is almost non-existent. In addition, the authors were unable to detect antibody-containing cells in cervical and endometrial biopsies of women locally "immunized" with horse spleen ferritin and bovine serum albumin. The need for further investigation with simple antigens and adequate immunological reagents is stressed.