Staphylococcus aureus and Streptococcus pyogenes colonize mucosal surfaces of the human body to cause disease. A group of virulence factors known as superantigens are produced by both of these organisms that allows them to cause serious diseases from the vaginal (staphylococci) or oral mucosa (streptococci) of the body. Superantigens interact with T cells and APCs to cause massive cytokine release to mediate the symptoms collectively known as toxic shock syndrome. In this study we demonstrate that another group of virulence factors, cytolysins, aid in the penetration of superantigens across vaginal mucosa as a representative nonkeratinized stratified squamous epithelial surface. The staphylococcal cytolysin α-toxin and the streptococcal cytolysin streptolysin O enhanced penetration of toxic shock syndrome toxin-1 and streptococcal pyrogenic exotoxin A, respectively, across porcine vaginal mucosa in an ex vivo model of superantigen penetration. Upon histological examination, both cytolysins caused damage to the uppermost layers of the vaginal tissue. In vitro evidence using immortalized human vaginal epithelial cells demonstrated that although both superantigens were proinflammatory, only the staphylococcal cytolysin α-toxin induced a strong immune response from the cells. Streptolysin O damaged and killed the cells quickly, allowing only a small release of IL-1β. Two separate models of superantigen penetration are proposed: staphylococcal α-toxin induces a strong proinflammatory response from epithelial cells to disrupt the mucosa enough to allow for enhanced penetration of toxic shock syndrome toxin-1, whereas streptolysin O directly damages the mucosa to allow for penetration of streptococcal pyrogenic exotoxin A and possibly viable streptococci.

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Superantigens interact with T lymphocytes and macrophages to cause T lymphocyte proliferation and overwhelming cytokine production, which lead to toxic shock syndrome. Staphylococcus aureus superantigen toxic shock syndrome toxin-1 is a major cause of menstrual toxic shock syndrome. In general, superantigen-secreting S. aureus remain localized at the vaginal surface, and the superantigen must therefore penetrate the vaginal mucosa to interact with underlying immune cells to cause toxic shock syndrome. A dodecapeptide region (toxic shock syndrome toxin-1 amino acids F119-D130), relatively conserved among superantigens, has been implicated in superantigen penetration of epithelium. The purpose of this study was to determine amino acids within this dodecapeptide region that are required for interaction with vaginal epithelium. Alanine mutations were constructed in S. aureus toxic shock syndrome toxin-1 amino acids D120 to D130. All mutants maintained superantigenicity, and selected mutants were lethal when given intravenously to rabbits. Toxic shock syndrome toxin-1 induces interleukin-8 from immortalized human vaginal epithelial cells; however three toxin mutants (S127A, T128A, and D130A) induced low levels of interleukin-8 compared to wild type toxin. When carboxy-terminal mutants (S127A to D130A) were administered vaginally to rabbits, D130A was nonlethal, while S127A and T128A demonstrated delayed lethality compared to wild type toxin. In a porcine ex vivo permeability model, mutant D130A penetrated vaginal mucosa more quickly than wild type toxin. Toxic shock syndrome toxin-1 residue D130 may contribute to binding an epithelial receptor, which allows it to penetrate vaginal mucosa, induce interleukin-8, and cause toxic shock syndrome.The staphylococcal superantigen toxic shock syndrome toxin-1 (TSST-1) is responsible for the majority of menstrual toxic shock syndrome (mTSS) cases and half of all nonmenstrual staphylococcal TSS cases (1,2). Staphylococcal enterotoxins (SEs) B and C are responsible for the other half of nonmenstrual TSS cases, whereas streptococcal pyrogenic exotoxin A (SPE A) and SPE C have been implicated as the main superantigens responsible for TSS cases caused by Streptococcus pyogenes (3-9). Superantigens were originally defined due to their unique mechanism of T lymphocyte stimulation (10). In the absence of normal antigen recognition, T cells are induced to proliferate when superantigens cross-bridge the variable region of the β chain of the T cell receptor (Vβ-TCR) and major histocompatibility complex Although the superantigenicity of TSST-1 has been thoroughly studied, the toxin's effects on other cell types, such as epithelial cells, have not been well defined. In the case of mTSS this is especially important as toxin-producing S. aureus commonly remain localized on the tampon and mucosal surface, whereas the superantigen must penetrate the vaginal mucosa in order to induce the systemic effects seen in TSS. Small amounts of TSST-1 have been shown to penetrate porcine vaginal t...

Menthol enhances penetration of NNN and nicotine through FM and BM in vitro, even after short exposure. This may reflect loading of a superficial epithelial reservoir (Squier, C. A., Kremer, M. J., Bruskin, A., Rose, A., & Haley, J. D., 1999. Oral mucosal permeability and stability of transforming growth factor beta-3 in vitro. Pharmaceutical Research, 16, 1557-1563.), thus delivering menthol and enhancing flux for several hours. Practical implications are for a potentially increased oral exposure to carcinogens among users of menthol-flavored cigarettes and chewing tobacco.

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