Human galectin-9 promotes the expansion of HIV reservoirs in vivo in humanized mice

Abstract

Objective:The human endogenous protein galectin-9 (Gal-9) reactivates latently HIV-infected cells in vitro and ex vivo, which may allow for immune-mediated clearance of these cells. However, Gal-9 also activates several immune cells, which could negatively affect HIV persistence by promoting chronic activation/exhaustion. This potential ‘double-edged sword’ effect of Gal-9 raises the question of the overall impact of Gal-9 on HIV persistence in vivo.Design:We used the BLT (bone marrow, liver, thymus) humanized mouse model to evaluate the impact of Gal-9 on HIV persistence in vivo during antiretroviral therapy (ART).Methods:Two independent cohorts of ART-suppressed HIV-infected BLT mice were treated with either recombinant Gal-9 or phosphate-buffered saline control. Plasma viral loads and levels of tissue-associated HIV DNA and RNA were measured by qPCR. Immunohistochemistry and HIV RNAscope were used to quantify CD4+ T, myeloid, and HIV RNA+ cells in tissues. T cell activation and exhaustion were measured by flow cytometry, and plasma markers of inflammation were measured by multiplex cytokine arrays.Results:Gal-9 did not induce plasma markers of inflammation or T cell markers of activation/exhaustion in vivo. However, the treatment significantly increased levels of tissue-associated HIV DNA and RNA compared to controls (P = 0.0007 and P = 0.011, respectively, for cohort I and P = 0.002 and P = 0.005, respectively, for cohort II). RNAscope validated the Gal-9 mediated induction of HIV RNA in tissue-associated myeloid cells, but not T cells.Conclusions:Our study highlights the overall adverse effects of Gal-9 on HIV persistence and the potential need to block Gal-9 interactions during ART-suppressed HIV infection.

Bispecific antibodies promote natural killer cell-mediated elimination of HIV-1 reservoir cells

“…The hIL-15 Tg NSG mice were generated as previously described [56][57][58] . All mice experiments were approved by the Wistar Institute Animal Care and Research Committee (protocol no.…”

“…Plasma viral loads were measured as previously described [56][57][58]60,61 . Briefly, viral RNA was extracted using a QIAamp Viral RNA Mini kit (QIAGEN).…”

Humanized mice for studying HIV latency and potentially its eradication

“…These compounds were given to HIV-infected humanized BLT mice exactly upon cessation of cART, and HIV RNA, measured in the plasma 48 h later, increased in 5/10 [79] and 3/9 [80] mice, while no increase was observed in the controls. Similarly, the impact of galectin-9 on HIV reactivation was investigated in HIV-infected humanized BLT mice [81]. Galectin-9 reactivates latently HIV-infected cells in vitro but may negatively affect HIV persistence by promoting chronic activation/exhaustion.…”