Centre for Virus Research

Lab head: Professor Anthony Cunningham
Location: Westmead Millennium Institute, Westmead Hospital

An Australian centre for HIV and Hepatitis Vilrology research, Westmead Millennium Institute, and one of the premier HIV reasearch laboratories in Australia.

Investigating HIV Driven Interferon Stimulated Genes in Macrophages

Primary supervisor: Anthony Cunningham

Research Background

The main target cell for HIV is the CD4 T-lymphocyte in which HIV explosively replicates resulting in rapid cell death. However HIV is also able to replicate other cells of the immune system. In macrophages a non-cytopathic infection occurs and these cells remain long lived. Macrophages therefore serve as a viral reservoir and act to constantly reseed the immune system of infected individuals with fresh virus. When cells come into contact with a foreign antigen they secrete antiviral molecules called interferons (IFN) which help to protect them and bystander cells from viral infection by inducing the expression of hundreds of IFN stimulated genes (ISG). These genes act to restrict viral replication via a wide array of mechanisms and the functions of many of them remains unknown. We have recently shown that HIV is able to directly induce a small subset of these ISGs in macrophages while at the same time blocking interferon induction.

 

Research Aim

To determine the effects of ISGs on HIV replication in macrophages.

 

Research Plan

We believe that the subset of HIV driven ISGs in macrophages will fall into two groups; those that act to restrict HIV replication and those that enhance it. In the first group we have already identified viperin and shown that this protein was able to restrict HIV replication. We predict that the transcription factor IFN regulatory factor 1 (IRF1) will fall into the second group of genes as that it may enhance HIV replication as the HIV promoter contains an IRF1 binding site.

We will initially check that the proteins encoded by these ISGs are also up regulated by HIV infection. Next, to investigate which of these two groups each HIV stimulated ISG falls into we will silence their expression via siRNA gene knock down and assess the effects on HIV replication kinetics. siRNA knock down will be confirmed at the gene level by quantitative (QPCR) and protein level by western blot and flow cytometry. In order to determine if IRF1 up-regulation by HIV is important for macrophage infection we will investigate the replication kinetics of a mutant HIV virus which has the IRF1 binding site deleted compared to a wild type virus.

This project will provide a comprehensive education in isolation of macrophages from human blood; the use of quantitative PCR (QPCR) in determining changes in gene expression levels; western blot and flow cytometry to determine protein expression levels.


Discipline: Infectious diseases and Immunology
Co-supervisors: NAJLA NASR
Keywords: HIV infection, immunobiology, Macrophages
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