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Minocycline attenuates HIV infection and reactivation in human CD4+ T cells
G. Szeto1, S. Barber2, R. Siliciano3, J. Clements1
1Johns Hopkins University School of Medicine, Department of Molecular and Comparative Pathobiology, Baltimore, United States, 2Booz Allen Hamilton, Rockville, United States, 3Johns Hopkins University School of Medicine, Department of Medicine, Baltimore, United States
Background: In our SIV-macaque model of HIV CNS disease, minocycline reduces inflammation, CNS disease and virus replication in the brain. Based on these observations, minocycline is currently in multi-center clinical trials to treat HIV CNS disease. In this study, we examine minocycline’s effect on HIV in human CD4+ T cells and their response to activation by co-stimulation.
Methods: CD4+ T lymphocytes were selected from PBMCs using magnetic-beads. Resting CD4+HLADR- T cells were isolated using bead depletion and cell sorting. FACS analysis assessed expression of GFP, markers of activation and proliferation. Real-time RT-PCR was used to quantitate HIVgag mRNA in supernatants.
Results: Minocycline causes a dose-dependent decrease in single-cycle infectivity of a psuedotyped HIV-GFP in CD4+ T cells. In a post-integration CD4+ T cell model of latency, minocycline reduces the expression of reporter GFP from reactivating cells, but not the frequency of reactivation in the population.
Minocycline treatment of CD4+ T cells significantly reduces the response to CD3/CD28 co-stimulation. Treated cells show attenuated progression of activation, including failure to down-regulate CD69 and CD45RA, and failure to up-regulate many activation/proliferation markers, including CD25 and LFA-I. Further, minocycline decreases cytokine production by activated cells and CD28 surface expression, suggesting minocycline may reduce the ability of CD4+ T cells to receive co-stimulatory signals.
Similar effects on activation/proliferation are seen in HIV-infected, resting CD4+HLADR- T cells isolated from patients on suppressive HAART regimens. Minocycline treatment decreases HIV gag mRNA in pooled supernatants after activation of these resting cells by co-stimulation, frequently below the limit of detection for the assay.
Conclusions: Our observations suggest that minocycline attenuates both HIV reactivation and spread by decreasing the responsiveness of human CD4+ T cells to activation signals. These data suggest minocycline may be useful as an adjunctive therapy in patients on HAART.
Supported by NIH MH070306, NS055648.