HIV and Dendritic Cells

Lab head: Tony Cunnigham
Location: Centre for Virus Research, Westmead Millennium Institute

Lab members: Tony Cunningham Andrew Harman Najla Nasr Valerie Marsden Rachel Botting
Funding: NHMRC / ACH2
Research approach equipment: Investigation of How HIV manipulates dendritic cells in order to fasciliate its transport to lymph nodes and transfer to T-cells
Publications:

HIV infection of dendritic cells subverts the IFN induction pathway via IRF-1 and inhibits type 1 IFN production.

Harman AN, Lai J, Turville S, Samarajiwa S, Gray L, Marsden V, Mercier S, Jones K, Nasr N, Rustagi A, Cumming H, Donaghy H, Mak J, Gale M Jr, Churchill M, Hertzog P, Cunningham AL.

The Role of Interferon Regulatory Factors in HIV Induction of Interferon in Dendritic Cells

Primary supervisor: Andrew Harman

Research Background

Dendritic cells (DC) are potent antigen presenting cells that form a link between the innate and adaptive immune systems. DCs in the genital mucosa represent the first line of contact between the immune system and HIV and act to pass the virus onto CD4 T-cells, which HIV explosively replicates in. DCs therefore play a vital role in the early stages of HIV infection. 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). We have recently shown that HIV is able to block the production of IFN by dendritic cells, yet at the same time is able to induce the expression of a few ISGs. The IFN regulatory factor (IRF) family are known to play key roles in modulating both IFN induction and the expression of ISGs.

Research Aim

To establish the role of specific IRFs in HIV induction of ISGs in DCs.

Research Plan

We have recently shown that following HIV infection of DCs a small subset of ISGs is up-regulated. This ISG subset all contain a common promoter binding site for IRF1, IRF2 and IRF7 and we have gone on to demonstrate and essential role for IRF1 in the induction of these genes. We would now like to examine the roles of IRF2 and IRF7 in this process. In addition we will examine the roles of other IRFs such as IRF4 and IRF8, which are among the subset of ISGs up-regulated by HIV.

Firstly we will determine whether the proteins encoded by these genes are also up-regulated. We will then express a variety of IRFs in 293T cells to examine the independent gene profiles that these transcription factors are able to trigger. We will also over express these proteins in DCs and determine the effects on HIV replication. Finally key IRFs will be silenced in DCs and the HIV infectivity levels determined alongside the ability to induce interferon.

This project will provide a comprehensive education in isolation of dendritic cells from human blood; HIV infectivity assays, quantitative PCR and microarrays (QPCR) for determining changes in gene expression levels; silencing RNA technology; western blot and flow cytometry to determine protein expression levels.

Discipline: Infectious diseases and Immunology
Co-supervisors: Najla Nasr, Anthony Cunningham
Keywords: Dendritic cells, HIV infection, Immune response
Contact: Email Andrew Harman