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Candidate polyanion microbicides inhibit HIV-1 infection and dissemination pathways in human cervical explants.

Fletcher PS, Wallace GS, Mesquita PM, Shattock RJ - Retrovirology (2006)

Bottom Line: While both compounds were virucidal for X4 HIV-1, neither was virucidal for R5 virus.Our results demonstrate that PRO 2000 is a potent inhibitor of R5 HIV-1 infection and dissemination pathways in human cervical explants.DxS, while demonstrating significant inhibition of R5 infection, was less active against DC mediated dissemination pathways.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Infection, Department of Cellular and Molecular Medicine, St George's, University of London, London, UK. pfletche@sgul.ac.uk

ABSTRACT

Background: Heterosexual intercourse remains the major route of HIV-1 transmission worldwide, with almost 5 million new infections occurring each year. Women increasingly bear a disproportionate burden of the pandemic, thus there is an urgent need to develop new strategies to reduce HIV-1 transmission that could be controlled by women themselves. The potential of topical microbicides to reduce HIV transmission across mucosal surfaces has been clearly identified, and some agents are currently under evaluation in clinical trials. Many of these "first generation" microbicides consist of polyanionic compounds designed to interfere with viral attachment. Here we have evaluated two candidate polyanion compounds in clinical trials, PRO 2000 and dextrin sulphate (DxS) to determine their safety and efficacy against in vitro HIV-1 and HSV-2 infection using cellular and tissue explant models.

Results: PRO 2000 and DxS potently inhibited infection by HIV-1 X4 and R5 isolates when present during viral exposure. However PRO 2000 required 10-fold and DxS 2000-fold more compound to block infection with R5 virus than X4. While both compounds were virucidal for X4 HIV-1, neither was virucidal for R5 virus. PRO 2000 efficiently inhibited infection of cervical explants and dissemination of virus by migratory DC. DxS was less active, able to completely inhibit cervical explant infection, but providing only partial reduction of virus dissemination by DC. PRO 2000, but not DxS, also inhibited HIV-1 binding to DC-SIGN+ cells and trans infection of co-cultured target cells. The inflammatory potential of both compounds was screened by measurement of cytokine production from cervical explants, and statistically significant increases were only observed for IL-1beta and RANTES following treatment with PRO 2000. Both compounds also demonstrated potent activity against HSV-2 infection of cervical epithelial cells.

Conclusion: Our results demonstrate that PRO 2000 is a potent inhibitor of R5 HIV-1 infection and dissemination pathways in human cervical explants. DxS, while demonstrating significant inhibition of R5 infection, was less active against DC mediated dissemination pathways. PRO 2000 has now entered human phase III efficacy trials.

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Polyanion inhibition of HIV-1BaL infection of cervical explants and transfer of virus from migratory cells. Ectocervical explants were exposed to HIV-1BaL for 2 hours in the presence of test compound. Following overnight culture, explants were separated from any cells that had migrated from the tissue and cultured separately. (i) Infection of cervical explants was determined by ELISA measurement of p24 antigen in culture supernatants. (ii) Migratory cells were co-cultured with permissive T cells (PM-1) and infection determined by p24 antigen in culture supernatants. Data represent the % HIV-1 infection observed following compound treatment when compared to tissue exposed to virus alone. Each compound was tested using n = 3 – 8 independent donors, where each condition was tested in triplicate. Compounds tested were A) PRO 2000 and B) Dextrin Sulphate. Inserted figures represent the mean ± SEM concentration inhibiting 50% HIV-1 infection (IC50) for each compound. Statistical analysis was completed using student's T-test with statistically significant changes marked * (p < 0.05), or *** (p < 0.005).
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Figure 3: Polyanion inhibition of HIV-1BaL infection of cervical explants and transfer of virus from migratory cells. Ectocervical explants were exposed to HIV-1BaL for 2 hours in the presence of test compound. Following overnight culture, explants were separated from any cells that had migrated from the tissue and cultured separately. (i) Infection of cervical explants was determined by ELISA measurement of p24 antigen in culture supernatants. (ii) Migratory cells were co-cultured with permissive T cells (PM-1) and infection determined by p24 antigen in culture supernatants. Data represent the % HIV-1 infection observed following compound treatment when compared to tissue exposed to virus alone. Each compound was tested using n = 3 – 8 independent donors, where each condition was tested in triplicate. Compounds tested were A) PRO 2000 and B) Dextrin Sulphate. Inserted figures represent the mean ± SEM concentration inhibiting 50% HIV-1 infection (IC50) for each compound. Statistical analysis was completed using student's T-test with statistically significant changes marked * (p < 0.05), or *** (p < 0.005).

Mentions: The potential of PRO 2000 and DxS to block infection of the female genital mucosa was investigated using ectocervical explants, cultured in a non-polarised manner as previously described [21,22]. Explants were treated with test compound (PRO 2000 or DxS) for 1 hour prior to exposure to R5 HIV-1BaL for 2 hours in the presence of compound as described in the Methods. Viral infection was evaluated by p24 released into culture supernatants. The activity of polyanions against HIV-1BaL infection of cervical explants was dose-dependent (Figure 3). Both PRO 2000 and DxS were able to completely inhibit infection at 1 mg/ml (p < 0.001), but allowed breakthrough of infection to occur at 100 μg/ml, with DxS being 10 fold better than PRO 2000 with an IC50 of 6.9 (± 1.6) versus 79.5 (± 3.7) μg/ml (Figure 3i).


Candidate polyanion microbicides inhibit HIV-1 infection and dissemination pathways in human cervical explants.

Fletcher PS, Wallace GS, Mesquita PM, Shattock RJ - Retrovirology (2006)

Polyanion inhibition of HIV-1BaL infection of cervical explants and transfer of virus from migratory cells. Ectocervical explants were exposed to HIV-1BaL for 2 hours in the presence of test compound. Following overnight culture, explants were separated from any cells that had migrated from the tissue and cultured separately. (i) Infection of cervical explants was determined by ELISA measurement of p24 antigen in culture supernatants. (ii) Migratory cells were co-cultured with permissive T cells (PM-1) and infection determined by p24 antigen in culture supernatants. Data represent the % HIV-1 infection observed following compound treatment when compared to tissue exposed to virus alone. Each compound was tested using n = 3 – 8 independent donors, where each condition was tested in triplicate. Compounds tested were A) PRO 2000 and B) Dextrin Sulphate. Inserted figures represent the mean ± SEM concentration inhibiting 50% HIV-1 infection (IC50) for each compound. Statistical analysis was completed using student's T-test with statistically significant changes marked * (p < 0.05), or *** (p < 0.005).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1590048&req=5

Figure 3: Polyanion inhibition of HIV-1BaL infection of cervical explants and transfer of virus from migratory cells. Ectocervical explants were exposed to HIV-1BaL for 2 hours in the presence of test compound. Following overnight culture, explants were separated from any cells that had migrated from the tissue and cultured separately. (i) Infection of cervical explants was determined by ELISA measurement of p24 antigen in culture supernatants. (ii) Migratory cells were co-cultured with permissive T cells (PM-1) and infection determined by p24 antigen in culture supernatants. Data represent the % HIV-1 infection observed following compound treatment when compared to tissue exposed to virus alone. Each compound was tested using n = 3 – 8 independent donors, where each condition was tested in triplicate. Compounds tested were A) PRO 2000 and B) Dextrin Sulphate. Inserted figures represent the mean ± SEM concentration inhibiting 50% HIV-1 infection (IC50) for each compound. Statistical analysis was completed using student's T-test with statistically significant changes marked * (p < 0.05), or *** (p < 0.005).
Mentions: The potential of PRO 2000 and DxS to block infection of the female genital mucosa was investigated using ectocervical explants, cultured in a non-polarised manner as previously described [21,22]. Explants were treated with test compound (PRO 2000 or DxS) for 1 hour prior to exposure to R5 HIV-1BaL for 2 hours in the presence of compound as described in the Methods. Viral infection was evaluated by p24 released into culture supernatants. The activity of polyanions against HIV-1BaL infection of cervical explants was dose-dependent (Figure 3). Both PRO 2000 and DxS were able to completely inhibit infection at 1 mg/ml (p < 0.001), but allowed breakthrough of infection to occur at 100 μg/ml, with DxS being 10 fold better than PRO 2000 with an IC50 of 6.9 (± 1.6) versus 79.5 (± 3.7) μg/ml (Figure 3i).

Bottom Line: While both compounds were virucidal for X4 HIV-1, neither was virucidal for R5 virus.Our results demonstrate that PRO 2000 is a potent inhibitor of R5 HIV-1 infection and dissemination pathways in human cervical explants.DxS, while demonstrating significant inhibition of R5 infection, was less active against DC mediated dissemination pathways.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Infection, Department of Cellular and Molecular Medicine, St George's, University of London, London, UK. pfletche@sgul.ac.uk

ABSTRACT

Background: Heterosexual intercourse remains the major route of HIV-1 transmission worldwide, with almost 5 million new infections occurring each year. Women increasingly bear a disproportionate burden of the pandemic, thus there is an urgent need to develop new strategies to reduce HIV-1 transmission that could be controlled by women themselves. The potential of topical microbicides to reduce HIV transmission across mucosal surfaces has been clearly identified, and some agents are currently under evaluation in clinical trials. Many of these "first generation" microbicides consist of polyanionic compounds designed to interfere with viral attachment. Here we have evaluated two candidate polyanion compounds in clinical trials, PRO 2000 and dextrin sulphate (DxS) to determine their safety and efficacy against in vitro HIV-1 and HSV-2 infection using cellular and tissue explant models.

Results: PRO 2000 and DxS potently inhibited infection by HIV-1 X4 and R5 isolates when present during viral exposure. However PRO 2000 required 10-fold and DxS 2000-fold more compound to block infection with R5 virus than X4. While both compounds were virucidal for X4 HIV-1, neither was virucidal for R5 virus. PRO 2000 efficiently inhibited infection of cervical explants and dissemination of virus by migratory DC. DxS was less active, able to completely inhibit cervical explant infection, but providing only partial reduction of virus dissemination by DC. PRO 2000, but not DxS, also inhibited HIV-1 binding to DC-SIGN+ cells and trans infection of co-cultured target cells. The inflammatory potential of both compounds was screened by measurement of cytokine production from cervical explants, and statistically significant increases were only observed for IL-1beta and RANTES following treatment with PRO 2000. Both compounds also demonstrated potent activity against HSV-2 infection of cervical epithelial cells.

Conclusion: Our results demonstrate that PRO 2000 is a potent inhibitor of R5 HIV-1 infection and dissemination pathways in human cervical explants. DxS, while demonstrating significant inhibition of R5 infection, was less active against DC mediated dissemination pathways. PRO 2000 has now entered human phase III efficacy trials.

Show MeSH
Related in: MedlinePlus