Infectious RNA: Human Immunodeficiency Virus (HIV) Biology, Therapeutic Intervention, and the Quest for a Vaccine

Different mechanisms mediate the toxicity of RNA. Genomic retroviral mRNA hijacks infected host cell factors to enable virus replication. The viral genomic RNA of the human immunodeficiency virus (HIV) encompasses nine genes encoding in less than 10 kb all proteins needed for replication in susceptible host cells. To do so, the genomic RNA undergoes complex alternative splicing to facilitate the synthesis of the structural, accessory, and regulatory proteins. However, HIV strongly relies on the host cell machinery recruiting cellular factors to complete its replication cycle. Antiretroviral therapy (ART) targets different steps in the cycle, preventing disease progression to the acquired immunodeficiency syndrome (AIDS). The comprehension of the host immune system interaction with the virus has fostered the development of a variety of vaccine platforms. Despite encouraging provisional results in vaccine trials, no effective vaccine has been developed, yet. However, novel promising vaccine platforms are currently under investigation.

Production of Recombinant HIV-1 p24-Nef Protein in Two Forms as Potential Candidate Vaccines in Three Vehicles

BACKGROUND

Different approaches have been investigated to develop a preventive or therapeutic vaccine, although none of them has been fully practical. Therapeutic vaccines against HIV-1 have been studied with the aim of eliminating the virus from reservoir cells with or without HAART (Highly Active Antiretroviral Therapy). Fusion proteins with the most immunogenic features among conserved regions can facilitate this achievement in such a variable virus. To achieve the most immunogenic and also conserved regions, bioinformatics tools are widely used to predict antigens' features before applying them.

OBJECTIVE

This study aimed at the in vitro evaluation of p24 -Nef fusion protein based on the previous in silico design to achieve a potential therapeutic subunit vaccine against HIV-1.

METHODS

The truncated form of p24-Nef using AAY flexible linker and the full protein were expressed and evaluated in the prokaryotic system and confirmed by western blotting. We also used pcDNA3.1 to transfect Lenti-X 293T cells. Moreover, lentiviral vectors were applied to produce recombinant virions harboring the genes of interest and cell transduction.

RESULTS

Both fusion proteins in a truncated and a full form were expressed and confirmed by Anti Nef polyclonal antibody in western blotting. Recombinant virions were generated and transduced Lenti-X 293T cells confirming by immunofluorescence microscope and p24 ELISA assay kit. Transduced cells were analyzed by SDS-PAGE and western blotting, which resulted in approved protein expression.

CONCLUSION

Fusion protein of p24 and Nef is well expressed in eukaryotic cell lines according to its pre-evaluated features by bioinformatics tools.