Glycosylphosphatidylinositol Anchor Deficiency Attenuates the Production of Infectious HIV-1 and Renders Virions Sensitive to Complement Attack

Abstract

Human immunodeficiency virus type 1 (HIV-1) escapes complement-mediated lysis (CML) by incorporating host regulators of complement activation (RCA) into its envelope. CD59, a key member of RCA, is incorporated into HIV-1 virions at levels that protect against CML. Since CD59 is a glycosylphosphatidylinositol-anchored protein (GPI-AP), we used GPI anchor-deficient Jurkat cells (Jurkat-7) that express intracellular CD59, but not surface CD59, to study the molecular mechanisms underlying CD59 incorporation into HIV-1 virions and the role of host proteins in virus replication. Compared to Jurkat cells, Jurkat-7 cells were less supportive to HIV-1 replication and more sensitive to CML. Jurkat-7 cells exhibited similar capacities of HIV-1 binding and entry to Jurkat cells, but were less supportive to viral RNA and DNA biosynthesis as infected Jurkat-7 cells produced reduced amounts of HIV-1 RNA and DNA. HIV-1 virions produced from Jurkat-7 cells were CD59 negative, suggesting that viral particles acquire CD59, and probably other host proteins, from the cell membrane rather than intracellular compartments. As a result, CD59-negative virions were sensitive to CML. Strikingly, these virions exhibited reduced activity of virus binding and were less infectious, implicating that GPI-APs may be also important in ensuring the integrity of HIV-1 particles. Transient expression of the PIG-A gene restored CD59 expression on the surface of Jurkat-7 cells. After HIV-1 infection, the restored CD59 was colocalized with viral envelope glycoprotein gp120/gp41 within lipid rafts, which is identical to that on infected Jurkat cells. Thus, HIV-1 virions acquire RCA from the cell surface, likely lipid rafts, to escape CML and ensure viral infectivity.

BCL6 represses antiviral resistance in follicular T helper cells

“…HIV-1 NL4-3 viral stock preparation and ex vivo infection. HIV-1 viral stock was prepared as described in our recent report [19]. In brief, viral DNA pNL4-3 (plasmid construct harbering full-length HIV genome NL4-3) was obtained from the NIH AIDS Reagent Program (Germantown, MD, USA).…”

Transcriptome analysis following enterovirus 71 and coxsackievirus A16 infection in respiratory epithelial cells

“…For example, Enk et al found that the herpes simplex virus (HSV)-1-encoded miR H8 could target the GPI anchoring pathway, which further reduced the expression levels of several immune-modulating proteins and finally enhanced viral spread and enabled evasion of elimination by natural killer cells [6]. Amet et al demonstrated that a deficiency of GPI-anchor could inhibit the production of infectious HIV-1 and render virions sensitive to complement attack [1]. Therefore, changes in the "GPI-anchor" pathway might promote the spread of EV-A71 and CV-A16.…”

Transcriptome analysis following EV-A71 and CV-A16 infection in respiratory epithelial cells

“…Among these pathways, the GPI-anchor is considered to play an important role in the infection and pathogenesis of many viruses. Amet et al demonstrated that the deficiency of GPI-anchor could attenuate the production of infectious HIV-1 and render virions sensitive to complement attack [24]. Therefore, changes in the "GPI-anchor" pathway might promote the spread of EV-A71 and CV-A16 virus.…”