HIV-1-based Virus-like Particles that Morphologically Resemble Mature, Infectious HIV-1 Virions.

Christopher A Gonelli,Georges Khoury,Damian F.J Purcell,Rob J Center

doi:10.3390/v11060507

Christopher A Gonelli, Georges Khoury + Show 2 more

Open Access

https://doi.org/10.3390/v11060507

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Journal: Viruses	Publication Date: Jun 2, 2019
Citations: 19	License type: CC BY 4.0

Affiliation: University of Melbourne, Peter Doherty Institute

Abstract

A prophylactic vaccine eliciting both broad neutralizing antibodies (bNAbs) to the HIV-1 envelope glycoprotein (Env) and strong T cell responses would be optimal for preventing HIV-1 transmissions. Replication incompetent HIV-1 virus-like particles (VLPs) offer the opportunity to present authentic-structured, virion-associated Env to elicit bNAbs, and also stimulate T cell responses. Here, we optimize our DNA vaccine plasmids as VLP expression vectors for efficient Env incorporation and budding. The original vector that was used in human trials inefficiently produced VLPs, but maximized safety by inactivating RNA genome packaging, enzyme functions that are required for integration into the host genome, and deleting accessory proteins Vif, Vpr, and Nef. These original DNA vaccine vectors generated VLPs with incomplete protease-mediated cleavage of Gag and were irregularly sized. Mutations to restore function within the defective genes revealed that several of the reverse transcriptase (RT) deletions mediated this immature phenotype. Here, we made efficient budding, protease-processed, and mature-form VLPs that resembled infectious virions by introducing alternative mutations that completely removed the RT domain, but preserved most other safety mutations. These VLPs, either expressed from DNA vectors in vivo or purified after expression in vitro, are potentially useful immunogens that can be used to elicit antibody responses that target Env on fully infectious HIV-1 virions.

Highlights

Following the discovery of human immunodeficiency virus type 1 (HIV-1) almost thirty-five years ago and its role as the etiological agent of acquired immunodeficiency syndrome (AIDS), the resulting pandemic has become one of the most significant infectious disease outbreaks in recent human history
The NC zinc (Zn2+ ) fingers were deleted by removing residues C15–C18 and C36–C39 (HXB2 numbering used here and throughout this manuscript); the reverse transcriptase (RT) was inactivated by the deletion of dNTP thumb (K65–L74), dNTP binding (D113–Y115), and active site (Y183–D186) residues; the RNase H active site was mutated (E38Q); the entire integrase domain (IN) domain was deleted; a frameshift mutation was introduced at D36 of Nef, which created a premature stop codon at position 37
HIV-1 virus-like particles (VLPs) are expressed by co-transfecting an envelope glycoprotein complex (Env)-deficient particle expression

Summary

Introduction

Following the discovery of human immunodeficiency virus type 1 (HIV-1) almost thirty-five years ago and its role as the etiological agent of acquired immunodeficiency syndrome (AIDS), the resulting pandemic has become one of the most significant infectious disease outbreaks in recent human history. The introduction of combined anti-retroviral therapy (cART) more than two decades ago has delayed disease progression and reduced mortality in patients from many developed countries [1]. An effective prophylactic vaccine for HIV-1 likely requires the elicitation of broadly neutralizing antibodies (bNAbs) against conserved epitopes on the envelope glycoprotein complex (Env), given the high amino acid variability of Env in circulating isolates [2]. Env receptor-binding (gp120) and membrane-spanning (gp41) domains [3,4]

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Conclusion