Observations from the CDC. The urgent need for new HIV/STD prevention options for women

Abasic phosphorothioate oligomers inhibit HIV-1 reverse transcription and block virus transmission across polarized ectocervical organ cultures

In the absence of universally available antiretroviral (ARV) drugs or a vaccine against HIV-1, microbicides may offer the most immediate hope for controlling the AIDS pandemic. The most advanced and clinically effective microbicides are based on ARV agents that interfere with the earliest stages of HIV-1 replication. Our objective was to identify and characterize novel ARV-like inhibitors, as well as demonstrate their efficacy at blocking HIV-1 transmission. Abasic phosphorothioate 2' deoxyribose backbone (PDB) oligomers were evaluated in a variety of mechanistic assays and for their ability to inhibit HIV-1 infection and virus transmission through primary human cervical mucosa. Cellular and biochemical assays were used to elucidate the antiviral mechanisms of action of PDB oligomers against both lab-adapted and primary CCR5- and CXCR4-utilizing HIV-1 strains, including a multidrug-resistant isolate. A polarized cervical organ culture was used to test the ability of PDB compounds to block HIV-1 transmission to primary immune cell populations across ectocervical tissue. The antiviral activity and mechanisms of action of PDB-based compounds were dependent on oligomer size, with smaller molecules preventing reverse transcription and larger oligomers blocking viral entry. Importantly, irrespective of molecular size, PDBs potently inhibited virus infection and transmission within genital tissue samples. Furthermore, the PDB inhibitors exhibited excellent toxicity and stability profiles and were found to be safe for vaginal application in vivo. These results, coupled with the previously reported intrinsic anti-inflammatory properties of PDBs, support further investigations in the development of PDB-based topical microbicides for preventing the global spread of HIV-1.

Adolescent girls' communication with "mothers" about topical microbicides

STUDY OBJECTIVE

Topical microbicides, a female-initiated method to protect against sexually transmitted infections (STI) and pregnancy, will only be effective if found acceptable. Mothers may have an influence on acceptability and use among adolescent girls. The current study examined the communication between girls and mothers to understand the potential predictors and nature of conversations regarding surrogate microbicide products.

DESIGN

Sexually experienced girls, 14 to 21 years, were recruited for a 6-month study examining microbicide acceptability. During face-to-face interviews, qualitative data were collected regarding communication between girls and mothers. Two independent raters coded the responses, which were organized into themes. Themes were interpreted according to the conceptual understanding of mother-daughter communication.

RESULTS

Fifty percent of the 171 girls with codable responses had a conversation with their mother. Higher levels of indirect parental monitoring were related to being more likely to have a conversation. Concrete events related to the study (i.e. receiving phone call from the researcher, having an appointment, or seeing the product) or inquiries by mothers appeared to promote conversation. Barriers to conversation included the private nature of the information and relationship issues between the mother and daughter. Conversations often addressed issues related to girls' participation in the study, although some conversations included global issues related to sexuality.

CONCLUSIONS

Girls may talk to their mothers about new products for STI prevention, and such conversations may provide opportunities to promote use.

In vitro evaluation of nonnucleoside reverse transcriptase inhibitors UC-781 and TMC120-R147681 as human immunodeficiency virus microbicides

The nonnucleoside reverse transcriptase inhibitors UC-781 and TMC120-R147681 (Dapivirine) effectively prevented human immunodeficiency virus (HIV) infection in cocultures of monocyte-derived dendritic cells and T cells, representing primary targets in sexual transmission. Both drugs had a favorable therapeutic index. A 24-h treatment with 1,000 nM UC-781 or 100 nM TMC120-R147681 prevented cell-free HIV infection, whereas 10-fold-higher concentrations blocked cell-associated HIV.

Comparative study of mechanisms of herpes simplex virus inactivation by sodium lauryl sulfate and n-lauroylsarcosine

The mechanisms of herpes simplex virus (HSV) inactivation by sodium lauryl sulfate (SLS) and n-lauroylsarcosine (LS), two anionic surfactants with protein denaturant potency, have been evaluated in cultured cells. Results showed that pretreatment of HSV type 1 (HSV-1) strain F and HSV-2 strain 333 with either surfactant inhibited, in a concentration- and time-dependent manner, their infectivities on Vero cells. SLS was a more potent inhibitor of HSV-2 strain 333 infectivity than LS with respect to the concentration (4.8-fold lower) and time (2.4-fold shorter) required to completely inactivate the virus. No inhibition of both herpesvirus strains infectivities was observed when Vero cells were pretreated with either surfactant. LS prevented the binding of HSV-2 strain 333 to cells without affecting the stable attachment and the rate of penetration into cells, whereas SLS exerted the opposite effect. Both SLS and LS inhibited, in a concentration-dependent manner, the HSV-2 strain 333-induced cytopathic effect, probably by affecting newly synthesized virions that come into contact with surfactant molecules present in culture medium. The pretreatment of HSV-2 strain 333 with specific combinations of SLS and LS concentrations inhibited the viral infectivity in a synergistic manner and resulted in only a small increase in their toxicities for exponentially growing Vero cells compared with that caused by each compound alone. Taken together, these results suggest that SLS and LS, alone or combined, could represent potent candidates as microbicides in topical vaginal formulations to prevent the transmission of herpes and possibly other pathogens that cause sexually transmitted diseases, including human immunodeficiency virus type 1.

Thermoreversible gel formulations containing sodium lauryl sulfate or n-Lauroylsarcosine as potential topical microbicides against sexually transmitted diseases

The microbicidal efficacies of two anionic surfactants, sodium lauryl sulfate (SLS) and n-lauroylsarcosine (LS), were evaluated in cultured cells and in a murine model of herpes simplex type 2 (HSV-2) intravaginal infection. In vitro studies showed that SLS and LS were potent inhibitors of the infectivity of HSV-2 strain 333. The concentrations of SLS which inhibit viral infectivity by 50% (50% inhibitory dose) and 90% (90% inhibitory dose) were 32.67 and 46.53 microM, respectively, whereas the corresponding values for LS were 141.76 and 225.30 microM. In addition, intravaginal pretreatment of mice with thermoreversible gel formulations containing 2.5% SLS or 2.5% LS prior to the inoculation of HSV-2 strain 333 completely prevented the development of genital herpetic lesions and the lethality associated with infection. Of prime interest, no infectious virus could be detected in mouse vaginal mucosa. Both formulations still provided significant protection when viral challenge was delayed until 1 h after pretreatment. Finally, intravaginal application of gel formulations containing 2.5% SLS or 2.5% LS once daily for 14 days to rabbits did not induce significant irritations to the genital mucosa, as demonstrated from macroscopic and histopathologic examinations. These results suggest that thermoreversible gel formulations containing SLS or LS could represent potent and safe topical microbicides for the prevention of HSV-2 and possibly other sexually transmitted pathogens, including human immunodeficiency virus.

Thermoreversible gel as a candidate barrier to prevent the transmission of HIV-1 and herpes simplex virus type 2

BACKGROUND

Sexually transmitted diseases (STDs) caused by HIV, herpes simplex virus (HSV), and other pathogens are spreading dramatically. The need to develop active products and vehicles to reduce this epidemic is urgent.

GOAL

The efficacy of a thermoreversible gel formulation as a possible barrier to prevent the transmission of pathogens causing STDs was evaluated.

STUDY DESIGN

This evaluation investigated the ability of the gel formulation to prevent infection of susceptible cells by HIV-1 and HSV-2 in vitro, the diffusion of radiolabeled herpes virus and micelles of polymer through an insertion membrane, and the electron microscopic appearance of herpes virus and gel alone or mixed together.

RESULTS

The gel formulation prevents infection of susceptible cells by HIV-1 and HSV-2. It acts as an effective artificial physical barrier against the herpes virus within the first 4 hours of incubation. Herpes virus is coated by the gel or entrapped within micelles of the gel, which could hinder its attachment to target cells and inhibit its infectivity.

CONCLUSION

This thermoreversible gel formulation represents an attractive matrix for the incorporation of microbicides to prevent the spread of STDs.

Sodium lauryl sulfate abrogates human immunodeficiency virus infectivity by affecting viral attachment

The microbicidal activity of sodium lauryl sulfate (SLS) against human immunodeficiency virus type 1 (HIV-1) was studied in cultured cells. Pretreatment of HIV-1(NL4-3) with SLS decreased, in a concentration-dependent manner, its infectivity when using 1G5 as target cells. In the absence of a viral pretreatment period or when 1G5 cells were pretreated with SLS, the surfactant-induced inactivation of viral infectivity was less pronounced, especially at concentrations between 375 and 550 microM. SLS had no effect on HIV-1 when the virus was adsorbed to 1G5 cells by a 2-h incubation period. SLS almost completely inhibited the fusion process by decreasing the attachment of HIV-1 to target cells. SLS also inhibited the infectivity of HIV-1-based luciferase reporter viruses pseudotyped with the amphotropic murine leukemia virus envelope (which enters cells in a CD4-, CCR5-, and CXCR4-independent manner), indicating that SLS may inactivate other envelope viruses. In contrast, no effect was seen with vesicular stomatitis virus envelope glycoprotein G (which enters cells through receptor-mediated endocytosis) pretreated with up to 700 microM SLS. SLS also decreased, in a dose-dependent manner, the HIV-1-dependent syncytium formation between 1G5 and J1.1 cells after a 24-h incubation. The reduction of luciferase activity was more pronounced when J1.1 cells (which express HIV-1 proteins on their surface) were pretreated with SLS rather than 1G5 cells. Taken together, our results suggest that SLS could represent a candidate of choice for use in vaginal microbicides to prevent the sexual transmission of HIV and possibly other pathogens causing sexually transmitted diseases.

Sodium dodecyl sulfate and C31G as microbicidal alternatives to nonoxynol 9: comparative sensitivity of primary human vaginal keratinocytes

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.

Acylcarnitine analogues as topical, microbicidal spermicides

Acylcarnitine analogues, (+)-6-Carboxylatomethyl-2-alkyl-4,4-dimethylmorpholinium (Z-n, where n = the number of carbons in the alkyl chain), synthesized in multi-gram quantities show in vitro activities as spermicides, anti-HIV agents, and inhibitors of the growth of Candida albicans. Activity improves with increasing chain length. Compound Z-15 is a candidate for further study as a topical, microbicidal spermicide.