HIV-1 is budded from CD4+ T lymphocytes independently of exosomes

Abstract

The convergence of HIV-1 budding and exosome biogenesis at late endosomal compartments called multivesicular bodies has fueled the debate on whether HIV-1 is budded from its target cells and transmitted in the form of exosomes. The point of contention appears to primarily derive from the types of target cells in question and lack of a well-defined protocol to separate exosomes from HIV-1. In this study, we adapted and established a simplified protocol to define the relationship between HIV-1 production and exosome biogenesis. Importantly, we took advantage of the newly established protocol to unequivocally show that HIV-1 was produced from CD4+ T lymphocytes Jurkat cells independently of exosomes. Thus, this study not only presents a simplified way to obtain highly purified HIV-1 virions for identification of host proteins packaged into virions, but also provides a technical platform that can be employed to define the relationship between exosome biogenesis and budding of HIV-1 or other viruses and its contributions to viral pathogenesis.

Exosomes from Human Immunodeficiency Virus Type 1 (HIV-1)-Infected Cells License Quiescent CD4 + T Lymphocytes To Replicate HIV-1 through a Nef- and ADAM17-Dependent Mechanism

“…Although the HIV-1 preparations we used to challenge CD4 ϩ T lymphocytes were obtained by an ultracentrifugation-based procedure excluding the coprecipitation of exosomes (32), the presence of residual contaminating exosomes in HIV-1 preparations cannot be formally ruled out. However, the lack of HIV-1 infection we observed when HIV-1 was given to resting CD4 ϩ T lymphocytes alone indicated that the presence of residual exosomes contaminating our HIV-1 preparations was negligible.…”

Emerging roles of extracellular vesicles in neurodegenerative disorders: focus on HIV-associated neurological complications

“…This, however, also poses a potential confound for the isolation of exosomes from HIV-1-infected materials. 34 In addition, studies on T cells and exosomes have been inconsistent and confounding. For example, some studies implicate that HIV-1 budding does not involve either endosomes or exosomes, 34, 35, 36 whereas other reports have shown that HIV-1 budding from T cells is closely associated with exosomes.…”

“…For example, some studies implicate that HIV-1 budding does not involve either endosomes or exosomes, 34, 35, 36 whereas other reports have shown that HIV-1 budding from T cells is closely associated with exosomes. 37 In this regard, Park and He 34 have shown that high-speed centrifugation with 20% sucrose cushion during the last step can yield exosome-free HIV-1 virions compared with centrifugation only. Herein the authors provided a technical platform that could be employed to define the relationship between exosome biogenesis and budding of HIV-1.…”

“…Herein the authors provided a technical platform that could be employed to define the relationship between exosome biogenesis and budding of HIV-1. 34 Though the small GTPase ARF6 and its effector PLD2 have an important role in exosome release, ARF6 is not involved in HIV-1 budding. 6 Early studies on HIV budding demonstrated that loss of the viral envelope Gag p6 domain caused a severe defect in virus budding.…”

Extracellular Vesicles and Their Convergence with Viral Pathways

“…Interestingly, HIV recruits members of the MVB ESCRT complex for proper HIV budding from the plasma membrane [98][99][100][101][102]. While in CD4+ T cells HIV release appears to be independent of exosomes [103], in monocyte-derived macrophages HIV can bud into endosomes [102,104]. However, several studies highlight that HIV-1 budding also in macrophages occurs primary at the plasma membrane [105][106][107].…”