Innate host defense of human vaginal and cervical mucosae

Host defense responses of the human female genital tract mucosa to pathogenic microbes and viruses are mediated in part by the release of antimicrobial substances into the overlying mucosal fluid. While host defense has long been considered a prominent function of vaginal and cervical mucosae, evidence that cationic antimicrobial peptides and proteins have fundamental roles in the innate host defense of this tissue has only recently become available. This chapter explores elements of the physical and chemical defense barriers of the cervicovaginal mucosa, which protect against infections of the lower genital tract. Cationic antimicrobial and antiviral polypeptide components of cervicovaginal fluid are discussed in detail, with special emphasis placed on the defensin family of peptides as well as polypeptides that are active against viruses such as HIV-1. The reader should be cognizant that each polypeptide by itself does not provide complete protection of the genital tract. On the contrary, the abundance and multiplicity of antimicrobial peptides and proteins suggest protection of the cervicovaginal mucosa may be best realized from the aggregate effector molecules.