CD4+ T-cells secrete IFN-γ http://www.selleckchem.com/products/BKM-120.html and drive B-cell maturation. Th17 cells play a role in host defense against extracellular pathogens by mediating the

recruitment of neutrophils and macrophages to infected tissues [25] and [26]. The female reproductive tract restricts entry of activated T-cells in the absence of inflammation or infection [27]. Consequently, parenteral vaccines that rely on cellular immunity to prevent STIs have not been successful. Recently, vaccines that elicit tissue-resident memory T-cell responses have been shown to be feasible [28] and [29] and may hold the key to a successful vaccination strategy against herpes simplex viruses and other sexually transmitted pathogens. In the male reproductive tract, keratinized stratified squamous epithelial cells cover the external surface of the penis. The male urethral orifice consists

of a non-keratinized stratified squamous epithelium that transitions in the penile shaft to a pseudostratified columnar epithelium. The urethral epithelium expresses several membrane-associated mucins that act as a first-line of defense [30]. The male reproductive tract is an immune privileged site. For example, tight junctions between Sertoli cells prevent entry of complement and immunoglobulins into the seminiferous tubules. This is referred to as the blood–testis barrier. This relative suppression of adaptive immunity is accompanied by an enhanced innate immune response against local infections. Far less is known about the mucosal immune system of the male

reproductive tract than is High Content Screening known about the female tract. Antimicrobial peptides are found in the testes, seminal vesicles, epididymis, and prostate [31]. As with the female reproductive tract, epithelial cells lining the male urethral tract express PRRs and are involved in antigen presentation [32]. Macrophages and dendritic cells are abundant in the prepuce and penile urethra and are found in the epididymis and prostate [33]. They are notably absent in the seminal vesicles. Neutrophils are present in the prepuce and variably present in the urethra, prostate, and epididymis. NK cells have been demonstrated in the prostate, testis, and prepuce. IgG is the main immunoglobulin found in seminal however plasma and it is serum-derived. IgA, mainly IgA1, is also present and is derived from serum and in situ production. B-cells that produce these antibodies are mainly found in the penile urethra and prostate. CD8+ T-cells and CD4+ T-cells are abundant in the penile urethra and also found in the vas deferens, epididymis, seminiferous tubules, and prepuce. It appears that the penile urethra, with the abundant distribution of immune cells, may be a major site of immune induction [32]. Microbiota” represent an assemblage of microorganisms present in a defined environment. The overwhelming majority of microbial species (>99%) resist cultivation in the laboratory [34] and [35].