secondary lymphoid Genistein tissues, and mucosal tissues. BLT mice were prepared for these experiments essentially as previously described . Briefly, preconditioned NOD/SCID gamma chain null mice implanted with thymus and liver tissue were transplanted with 2105 to 3105 autologous human fetal liver CD34 cells and monitored for human engraftment. Mice were maintained at the Animal Resources Center of UT Southwestern Medical Center at Dallas or the Division of Laboratory Animal Medicine at the University of North Carolina at Chapel Hill in accordance with protocols approved by each institution’s Institutional Animal Care and Use Committee. Prior to HIV infection, all the BLT mice used for these experiments were characterized for human reconstitution.
The peripheral blood of these mice contained an average of 51% human CD45cells of Vascular Disrupting Agent which an average of 83% were human CD4 T cells. The general approach used to conduct the experiments described below is outlined in Fig. 1A. Humanized BLT mice are susceptible to vaginal, rectal, and intravenous HIV infection , which results in systemic viral dissemination and robust viral replication in peripheral blood . The course of HIV infection in BLT mice closely mimics that observed in humans, and currently prescribed therapeutic antiretrovirals exhibit efficacy in humanized BLT mice . We infected BLT mice with CCR5 tropic HIV as previously described and monitored their plasma viral loads as previously described , with a limit of detection of 750 copies per ml of mouse plasma.
The low sensitivity of our standard assay compared to that of the standard clinical assay is due to the lower volume of plasma that can be obtained on a regular basis from mice. Infected BLT mice received ART consisting of daily intraperitoneal injections of emtricitabine paraffin , tenofovir disoproxil fumarate , and raltegravir . ART was very efficient at reducing plasma viral loads to below the limit of detection in as few as 11 days . We also noted that, similar to what occurs in patients taking ART , during structured treatment interruption, there is a rapid rebound of plasma viremia to levels comparable to those detected prior to therapy . In addition to the evaluation of plasma viremia during ART, we also assessed the effect of ART on systemic virus production in BLT mice.
Tissues harvested from one infected BLT mouse receiving ART and two untreated infected controls were examined for the presence of viral RNA . ART dramatically reduced viral RNA levels in all the tissues examined compared to the case in the control animals , and the greatest reductions were observed in peripheral blood and thymocytes. The least pronounced reductions in viral RNA levels were noted in lymph nodes and liver . It should be noted that the viral RNA levels in the control mice reflect both the relative levels of humanization and the CCR5 expression on T cells in each tissue . Together, these data establish that ART consisting of a well characterized combination of FDA approved therapeutic antiretroviral drugs is capable of suppressing HIV replication in BLT mice and demonstrate that, like in humans and nonhuman primates, the infection persists for the duration of the treatment. HIV persistence during ART can be due to latently infected resting CD4 .