Dendritic Cells (DC) present in the anogenital mucosa are one of the first cells to encounter invading pathogens during sexual intercourse. They bind pathogens via C-type lectin receptors (CLR) expressed on their surface which results in endocytosis and subsequent processing via the endolysosomal system.
The anogenital mucosa contains various tissue types which represent unique opportunities and barriers for invading pathogens and each of these tissue types need to be considered separately in terms of transmission of STIs. The mucosal surface of the vagina, ectocervix, anus and foreskin consist of a multilayered stratified squamous epithelium which represents a significant barrier, whereas as that of the rectum and endocervix consists of a thin and fragile columnar epithelial monolayer which is easily breached. In addition, differences exist between these two surfaces at different anatomical locations. For example the endocervix is covered in acidic mucus whereas the rectum is not. Furthermore these tissues differ in their underlying connective tissue, with dermis underlying squamous epithelium and lamina propria underlying columnar epithelium.
The different anogenital tissues contain a variety of DCs subsets which is likely driven by the unique cytokine environment of each tissue. Each subset expresses unique combinations of CLRs which affect the way they interact with different pathogens and the efficiency by which they can process them. Although DC subsets found within squamous epithelium and dermis at non mucosal sites are well characterised very little human data is available concerning differences between DC subsets in different anogenital tissues particularly lamina propria DC subsets.
Here we present data comparing the repertoire of CLR expression on human DC subsets derived from all the anogenital tissues. Critically we identify key differences in pathogen binding receptor expression and we have also have identified novel previously unidentified tissue specific DC subsets.