Secretory immune system of the female reproductive tract: I. Immunoglobulin and secretory component-containing cells.

We have investigated tissues from the female reproductive tract to determine whether the distribution of cells involved in the formation of secretory immunoglobulin A (IgA) molecules is analogous to that described for intestines, bronchus, and mammary and salivary glands. Fresh tissues from fallopian tube, ovary, uterus, and vagina were obtained, and sections were stained with fluorochrome-labeled polyclonal or monoclonal antibodies specific for IgG, IgA, IgA1, and IgA2 subclasses; IgM; secretory component; and J chain. Subepithelial plasma cells were identified in each specimen of fallopian tube, endocervix, ectocervix, and vagina. Approximately two-thirds of the immunoglobulin-positive cells contained IgA and J chain, indicating that they produced polymeric IgA. In comparison to tissues such as spleen and bone marrow, where IgA1-positive cells are produced, we found a high proportion of IgA2-positive cells in fallopian tube, cervix, and vagina. Epithelial cells in fallopian tube and endocervix contained secretory component. These data indicate that secretory IgA, which provides the first line of defense against invading pathogens, is produced locally in tissues of the female reproductive tract.