Sodium Dodecyl Sulfate and C31G as Microbicidal Alternatives to Nonoxynol 9: Comparative Sensitivity of Primary Human Vaginal Keratinocytes

Abstract

A broad-spectrum vaginal microbicide must be effective against a variety of sexually transmitted disease pathogens and be minimally toxic to the cell types found within the vaginal epithelium, including vaginal keratinocytes. We assessed the sensitivity of primary human vaginal keratinocytes to potential topical vaginal microbicides nonoxynol-9 (N-9), C31G, and sodium dodecyl sulfate (SDS). Direct immunofluorescence and fluorescence-activated cell sorting analyses demonstrated that primary vaginal keratinocytes expressed epithelial cell-specific keratin proteins. Experiments that compared vaginal keratinocyte sensitivity to each agent during a continuous, 48-h exposure demonstrated that primary vaginal keratinocytes were almost five times more sensitive to N-9 than to either C31G or SDS. To evaluate the effect of multiple microbicide exposures on cell viability, primary vaginal keratinocytes were exposed to N-9, C31G, or SDS three times during a 78-h period. In these experiments, cells were considerably more sensitive to C31G than to N-9 or SDS at lower concentrations within the range tested. When agent concentrations were chosen to result in an endpoint of 25% viability after three daily exposures, each exposure decreased cell viability at the same constant rate. When time-dependent sensitivity during a continuous 48-h exposure was examined, exposure to C31G for 18 h resulted in losses in cell viability not caused by either N-9 or SDS until at least 24 to 48 h. Cumulatively, these results reveal important variations in time-and concentration-dependent sensitivity to N-9, C31G, or SDS within populations of primary human vaginal keratinocytes cultured in vitro. These investigations represent initial steps toward both in vitro modeling of the vaginal microenvironment and studies of factors that impact the in vivo efficacy of vaginal topical microbicides.

Mandelic Acid Condensation Polymer: Novel Candidate Microbicide for Prevention of Human Immunodeficiency Virus and Herpes Simplex Virus Entry

“…Third, SAMMA exhibits no cytotoxicity in tissue cultures using primary cervical cells, human mac- rophages, or PBMC. These results are in contrast with those obtained for N-9, sodium dodecyl sulfate, or C31G, which are toxic to primary vaginal cells (16,20). Fourth, SAMMA is soluble in water and saline, probably inexpensive to manufacture, and likely to be easily formulated.…”

A Review of Current Intravaginal Drug Delivery Approaches Employed for the Prophylaxis of HIV/AIDS and Prevention of Sexually Transmitted Infections

“…Short pre-treatment both of isolated cells and human cervical tissue explants, with low concentrations of UC781 provided a strong barrier to subsequent virus infection by cell-free or cell-associated HIV-1 (126,127). UC781 is readily formulated as an appropriate carrier for vaginal application in the form of Replens® Gel (Anglian Pharma, Hertfordshire, UK).…”

Comparative In Vitro Sensitivities of Human Immune Cell Lines, Vaginal and Cervical Epithelial Cell Lines, and Primary Cells to Candidate Microbicides Nonoxynol 9, C31G, and Sodium Dodecyl Sulfate

“…Assessments of in vitro microbicide cytotoxicity should also include experiments using vaginal and cervical epithelial cells. Human vaginal keratinocyte (HVK) cultures, described in previous studies (20), were compared to immortalized VK2/E6E7 vaginal epithelial cells (12) and HeLa cells (human cervical carcinoma; ATCC CCL-2) in experiments using N-9, C31G, and SDS (Fig. 6).…”

“…As a consequence, investigations are being directed toward discovery and development of numerous second-generation microbicidal agents. Experimental efforts reported herein have focused primarily on characterization of two potential microbicides, C31G (6,10,20,29) and sodium dodecyl sulfate (SDS), which have in vitro activity against STD pathogens, including HIV-1 and herpes simplex virus type 2 (16,21,22,25). In addition, SDS is an attractive candidate microbicide due to its lower cytotoxicity (16,20,21) and ability to inactivate papillomaviruses (16,17,22).…”

“…1). Immediately following in vitro exposure to each agent for 10 min, 2 h, 8 h, or 48 h, cell viability was determined using an MTT assay (24) as described earlier (20,21). After a 10-min exposure (Fig.…”