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Antiretroviral pre-exposure prophylaxis prevents vaginal transmission of HIV-1 in humanized BLT mice.

Denton PW, Estes JD, Sun Z, Othieno FA, Wei BL, Wege AK, Powell DA, Payne D, Haase AT, Garcia JV - PLoS Med. (2008)

Bottom Line: Despite the urgency to develop and implement novel approaches capable of preventing HIV transmission, this process has been hindered by the lack of adequate small animal models for preclinical efficacy and safety testing.Effects of HIV-1 infection include CD4+ T cell depletion in gut-associated lymphoid tissue (GALT) that closely mimics what is observed in HIV-1-infected humans.We also show that pre-exposure prophylaxis with antiretroviral drugs is a highly effective method for preventing vaginal HIV-1 transmission.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America.

ABSTRACT

Background: Worldwide, vaginal transmission now accounts for more than half of newly acquired HIV-1 infections. Despite the urgency to develop and implement novel approaches capable of preventing HIV transmission, this process has been hindered by the lack of adequate small animal models for preclinical efficacy and safety testing. Given the importance of this route of transmission, we investigated the susceptibility of humanized mice to intravaginal HIV-1 infection.

Methods and findings: We show that the female reproductive tract of humanized bone marrow-liver-thymus (BLT) mice is reconstituted with human CD4+ T and other relevant human cells, rendering these humanized mice susceptible to intravaginal infection by HIV-1. Effects of HIV-1 infection include CD4+ T cell depletion in gut-associated lymphoid tissue (GALT) that closely mimics what is observed in HIV-1-infected humans. We also show that pre-exposure prophylaxis with antiretroviral drugs is a highly effective method for preventing vaginal HIV-1 transmission. Whereas 88% (7/8) of BLT mice inoculated vaginally with HIV-1 became infected, none of the animals (0/5) given pre-exposure prophylaxis of emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF) showed evidence of infection (Chi square = 7.5, df = 1, p = 0.006).

Conclusions: The fact that humanized BLT mice are susceptible to intravaginal infection makes this system an excellent candidate for preclinical evaluation of both microbicides and pre-exposure prophylactic regimens. The utility of humanized mice to study intravaginal HIV-1 transmission is particularly highlighted by the demonstration that pre-exposure prophylaxis can prevent intravaginal HIV-1 transmission in the BLT mouse model.

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Pre-exposure FTC/TDF Treatment Resulted in Complete Protection of Humanized BLT Mice from Intravaginal HIV-1 Transmission(A) Box plot depicting real-time PCR levels of HIV-1 viral DNA in the indicated tissues for HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. (Viral DNA copies per million CD4+ T cells shown.) HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4).(B) Box plot depicting virus rescue results from HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. Virus rescue data expressed as pg/ml of p24 per 1 × 105 CD4+ T cells cocultured with PHA/IL2-activated peripheral blood lymphocyte from a seronegative donor. HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4). In the box plots, the middle line indicates the median of the data, whereas the vertical line extends from lowest to the highest values. Dashed lines indicate the limit of detection for each assay.(C) In situ hybridization analysis to determine the presence of productively HIV-1–infected cells in the indicated tissues from HIV-1–infected or FTC/TDF-treated BLT mice (bars indicate 50 μm). Note the lack of HIV-1 in the BLT mice that received pre-exposure prophylaxis with FTC/TDF. HIV-1 infected (n = 4) and FTC/TDF + HIV-1 (n = 3).BM, bone marrow; LPL, lamina propria lymphocytes; Thymic Org., implanted thymic organoid; SI, small intestine.
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pmed-0050016-g006: Pre-exposure FTC/TDF Treatment Resulted in Complete Protection of Humanized BLT Mice from Intravaginal HIV-1 Transmission(A) Box plot depicting real-time PCR levels of HIV-1 viral DNA in the indicated tissues for HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. (Viral DNA copies per million CD4+ T cells shown.) HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4).(B) Box plot depicting virus rescue results from HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. Virus rescue data expressed as pg/ml of p24 per 1 × 105 CD4+ T cells cocultured with PHA/IL2-activated peripheral blood lymphocyte from a seronegative donor. HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4). In the box plots, the middle line indicates the median of the data, whereas the vertical line extends from lowest to the highest values. Dashed lines indicate the limit of detection for each assay.(C) In situ hybridization analysis to determine the presence of productively HIV-1–infected cells in the indicated tissues from HIV-1–infected or FTC/TDF-treated BLT mice (bars indicate 50 μm). Note the lack of HIV-1 in the BLT mice that received pre-exposure prophylaxis with FTC/TDF. HIV-1 infected (n = 4) and FTC/TDF + HIV-1 (n = 3).BM, bone marrow; LPL, lamina propria lymphocytes; Thymic Org., implanted thymic organoid; SI, small intestine.

Mentions: Finally, to confirm the lack of infection in FTC/TDF-treated animals shown in Figures 2, 3, and 4, three additional approaches were utilized. DNA isolated from cells obtained from different organs of either HIV-1–infected or FTC/TDF-treated BLT mice was analyzed by quantitative real-time PCR for HIV-1 viral DNA. Whereas the tissues from HIV-1–infected mice were clearly positive for viral DNA, samples from pre-exposure FTC/TDF-treated mice were consistently negative (Figure 6A). Cells isolated from multiple organs of HIV-1–infected or FTC/TDF-treated BLT mice were cocultured with PHA/IL2-activated peripheral blood lymphocytes from a seronegative donor. Virus was readily rescued from cells isolated from tissues obtained from the HIV-1–infected mice (Figure 6B). In contrast, no virus was rescued from any of the tissues obtained from the BLT mice treated with FTC/TDF. Last, we used in situ hybridization to determine the presence of productively infected cells in HIV-1–infected or FTC/TDF-treated BLT mice. Productively HIV-1–infected cells were readily observed in tissues from the HIV-1–infected BLT mice (Figure 6C). In contrast, no productively infected cells were found in any of the tissues from the FTC/TDF-treated mice. These results verify the protection afforded by this pre-exposure prophylaxis approach to the prevention of intravaginal transmission of HIV-1 in BLT mice.


Antiretroviral pre-exposure prophylaxis prevents vaginal transmission of HIV-1 in humanized BLT mice.

Denton PW, Estes JD, Sun Z, Othieno FA, Wei BL, Wege AK, Powell DA, Payne D, Haase AT, Garcia JV - PLoS Med. (2008)

Pre-exposure FTC/TDF Treatment Resulted in Complete Protection of Humanized BLT Mice from Intravaginal HIV-1 Transmission(A) Box plot depicting real-time PCR levels of HIV-1 viral DNA in the indicated tissues for HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. (Viral DNA copies per million CD4+ T cells shown.) HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4).(B) Box plot depicting virus rescue results from HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. Virus rescue data expressed as pg/ml of p24 per 1 × 105 CD4+ T cells cocultured with PHA/IL2-activated peripheral blood lymphocyte from a seronegative donor. HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4). In the box plots, the middle line indicates the median of the data, whereas the vertical line extends from lowest to the highest values. Dashed lines indicate the limit of detection for each assay.(C) In situ hybridization analysis to determine the presence of productively HIV-1–infected cells in the indicated tissues from HIV-1–infected or FTC/TDF-treated BLT mice (bars indicate 50 μm). Note the lack of HIV-1 in the BLT mice that received pre-exposure prophylaxis with FTC/TDF. HIV-1 infected (n = 4) and FTC/TDF + HIV-1 (n = 3).BM, bone marrow; LPL, lamina propria lymphocytes; Thymic Org., implanted thymic organoid; SI, small intestine.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2194746&req=5

pmed-0050016-g006: Pre-exposure FTC/TDF Treatment Resulted in Complete Protection of Humanized BLT Mice from Intravaginal HIV-1 Transmission(A) Box plot depicting real-time PCR levels of HIV-1 viral DNA in the indicated tissues for HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. (Viral DNA copies per million CD4+ T cells shown.) HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4).(B) Box plot depicting virus rescue results from HIV-1–infected (white) and FTC/TDF-treated plus HIV-1–exposed (red) BLT mice. Virus rescue data expressed as pg/ml of p24 per 1 × 105 CD4+ T cells cocultured with PHA/IL2-activated peripheral blood lymphocyte from a seronegative donor. HIV-1 infected (n = 2) and FTC/TDF + HIV-1 (n = 4). In the box plots, the middle line indicates the median of the data, whereas the vertical line extends from lowest to the highest values. Dashed lines indicate the limit of detection for each assay.(C) In situ hybridization analysis to determine the presence of productively HIV-1–infected cells in the indicated tissues from HIV-1–infected or FTC/TDF-treated BLT mice (bars indicate 50 μm). Note the lack of HIV-1 in the BLT mice that received pre-exposure prophylaxis with FTC/TDF. HIV-1 infected (n = 4) and FTC/TDF + HIV-1 (n = 3).BM, bone marrow; LPL, lamina propria lymphocytes; Thymic Org., implanted thymic organoid; SI, small intestine.
Mentions: Finally, to confirm the lack of infection in FTC/TDF-treated animals shown in Figures 2, 3, and 4, three additional approaches were utilized. DNA isolated from cells obtained from different organs of either HIV-1–infected or FTC/TDF-treated BLT mice was analyzed by quantitative real-time PCR for HIV-1 viral DNA. Whereas the tissues from HIV-1–infected mice were clearly positive for viral DNA, samples from pre-exposure FTC/TDF-treated mice were consistently negative (Figure 6A). Cells isolated from multiple organs of HIV-1–infected or FTC/TDF-treated BLT mice were cocultured with PHA/IL2-activated peripheral blood lymphocytes from a seronegative donor. Virus was readily rescued from cells isolated from tissues obtained from the HIV-1–infected mice (Figure 6B). In contrast, no virus was rescued from any of the tissues obtained from the BLT mice treated with FTC/TDF. Last, we used in situ hybridization to determine the presence of productively infected cells in HIV-1–infected or FTC/TDF-treated BLT mice. Productively HIV-1–infected cells were readily observed in tissues from the HIV-1–infected BLT mice (Figure 6C). In contrast, no productively infected cells were found in any of the tissues from the FTC/TDF-treated mice. These results verify the protection afforded by this pre-exposure prophylaxis approach to the prevention of intravaginal transmission of HIV-1 in BLT mice.

Bottom Line: Despite the urgency to develop and implement novel approaches capable of preventing HIV transmission, this process has been hindered by the lack of adequate small animal models for preclinical efficacy and safety testing.Effects of HIV-1 infection include CD4+ T cell depletion in gut-associated lymphoid tissue (GALT) that closely mimics what is observed in HIV-1-infected humans.We also show that pre-exposure prophylaxis with antiretroviral drugs is a highly effective method for preventing vaginal HIV-1 transmission.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America.

ABSTRACT

Background: Worldwide, vaginal transmission now accounts for more than half of newly acquired HIV-1 infections. Despite the urgency to develop and implement novel approaches capable of preventing HIV transmission, this process has been hindered by the lack of adequate small animal models for preclinical efficacy and safety testing. Given the importance of this route of transmission, we investigated the susceptibility of humanized mice to intravaginal HIV-1 infection.

Methods and findings: We show that the female reproductive tract of humanized bone marrow-liver-thymus (BLT) mice is reconstituted with human CD4+ T and other relevant human cells, rendering these humanized mice susceptible to intravaginal infection by HIV-1. Effects of HIV-1 infection include CD4+ T cell depletion in gut-associated lymphoid tissue (GALT) that closely mimics what is observed in HIV-1-infected humans. We also show that pre-exposure prophylaxis with antiretroviral drugs is a highly effective method for preventing vaginal HIV-1 transmission. Whereas 88% (7/8) of BLT mice inoculated vaginally with HIV-1 became infected, none of the animals (0/5) given pre-exposure prophylaxis of emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF) showed evidence of infection (Chi square = 7.5, df = 1, p = 0.006).

Conclusions: The fact that humanized BLT mice are susceptible to intravaginal infection makes this system an excellent candidate for preclinical evaluation of both microbicides and pre-exposure prophylactic regimens. The utility of humanized mice to study intravaginal HIV-1 transmission is particularly highlighted by the demonstration that pre-exposure prophylaxis can prevent intravaginal HIV-1 transmission in the BLT mouse model.

Show MeSH
Related in: MedlinePlus