Immunohistochemical Characterization of the Human Sublingual Mucosa

The sublingual locus has recently received great attention as a delivery site for various immunotherapies, including those that induce allergen-specific tolerance, and for vaccines that generate protective immunity. To further understand the immune functions of the human sublingual mucosa, we characterized the distribution of various immunocytes therein by immunohistochemistry. We identified professional antigen presenting cells (APCs), including Langerhans cells (LCs) and macrophages. CD1a+ and langerin+ LCs were further found to be distributed in the basal and supra-basal layers of the epithelium, and macrophages were identified in the lamina propria. HLA-DR+ cells were observed in both the epithelium and the lamina propria, which mirrors the tissue distribution of LCs and macrophages within these tissues. CD3+, CD4+, and CD8+ T cells were found to be distributed along the basal layer of the epithelium and also in the lamina propria. Although B cells, plasma cells, and Foxp3+ regulatory T cells (Tregs) were only occasionally observed in the human sublingual mucosa in the absence of inflammation, they did show enrichment at inflammatory sites. Hence, we have further elucidated the immune cell component distribution in human sublingual mucosa

Sublingual immunization with an HIV subunit vaccine induces antibodies and cytotoxic T cells in the mouse female genital tract.

International audienceA vaccine against heterosexual transmission by human immunodeficiency virus (HIV) should generate cytotoxic and antibody responses in the female genital tract and in extra-genital organs. We report that sublingual immunization with HIV-1 gp41 and a reverse transcriptase polypeptide coupled to the cholera toxin B subunit (CTB) induced gp41-specific IgA antibodies and antibody-secreting cells, as well as reverse transcriptase-specific CD8 T cells in the genital mucosa, contrary to intradermal immunization. Conjugation of the reverse transcriptase peptide to CTB favored its cross-presentation by human dendritic cells to a T cell line from an HIV(+) patient. Sublingual vaccination could represent a promising vaccine strategy against heterosexual transmission of HIV-1