Drummer/Poumbourios Group

Viral Entry and Vaccines

Hep-c-_green_-from-heidi-drummer

Overview

Image: HCV infected liver cells. The cytoplasm of infected cells can be seen stained in green, nuclei are stained in orange.

The viral entry and vaccine laboratory conducts studies into two of the world’s most destructive human pathogens – Human Immunodeficiency Virus (HIV) and Hepatitis C Virus (HCV).

HIV infects more than 37 million people world-wide and results in almost two million deaths each year. HCV is estimated to chronically infect three percent of the world’s population causing 350 million deaths each year. In the United States, deaths due to HCV now outnumber those caused by HIV, and HCV is now the major indicator of liver transplants in the developed world.

No vaccines are available for HCV or HIV.

Whilst the use of highly-active antiretroviral therapy has seen a dramatic increase in the life expectancy of HIV infected people, the virus still cannot be eliminated. Over time, viruses can become resistant to the antiviral agents and patients may succumb to AIDS.

In the case of HCV, direct acting antiviral therapies are now available in the market place and whilst there has been a dramatic improvement in the number of people achieving a sustained virological response, the high cost of treatment will restrict their availability. As such, it is unlikely that sufficient people will receive treatment to reduce the burden of disease.

Like other viruses, HIV and HCV attach to the surface of target cells via specific interactions with cellular receptors. Both HIV and HCV must then undergo the process of membrane fusion before they can enter the cell and begin their replication cycle.

The viral entry and vaccine laboratory aims to gain a better understanding of how viruses attach to and enter target cells. The surface of HIV and HCV particles are decorated with the viral glycoproteins that mediate specific interactions with host cell receptors. Binding of the viral glycoproteins to these receptors induces conformational changes that prime the glycoproteins to mediate viral fusion. During viral fusion, the lipid bilayer of the virus and host cell merge and begin to form a small pore. Expansion of this pore then allows the contents of the virus to be delivered and initiates viral replication.

The viral glycoproteins are major targets of the antibody response during infection. These antibodies can block the ability of the virus to interact with the cellular receptors, or they can prevent the conformational changes required to mediate viral fusion and are termed neutralising antibodies. In the case of HIV and HCV, the viruses have evolved mechanisms to evade this neutralising antibody response and have hampered efforts to produce vaccines. In addition, both HIV and HCV are highly variable pathogens and so it is necessary to produce a vaccine that has the ability to prevent infection of multiple clades/genotypes that circulate globally.

The viral entry and vaccine laboratory aims to understand how virus entry occurs and develop novel vaccine candidates against HIV and HCV.

Objectives

HCV studies

  • Development of a prophylactic vaccine for HCV
  • Understanding the role of the variable regions in modulating virus entry and neutralisation by antibody
  • Expression of recombinant HCV glycoproteins for structure determination
  • Virus and antibody evolution.

HIV studies

  • The role of conformational signalling between gp120 and gp41 in HIV entry
  • The role of the polar segment and membrane proximal external region in HIV entry
  • Identification of functional linkages between gp120 and gp41 -Development of novel HIV vaccine candidates.

Highlights

  1. Drummer HE. 2014. Challenges to the development of vaccines to hepatitis C virus that elicit neutralizing antibodies. Front Microbiol 5:329.
  2. Sacks-Davis R, Aitken CK, Higgs P, Spelman T, Pedrana AE, Bowden S, Bharadwaj M, Nivarthi UK, Suppiah V, George J, Grebely J, Drummer HE, Hellard M. 2013. High rates of hepatitis C virus reinfection and spontaneous clearance of reinfection in people who inject drugs: a prospective cohort study. PLoS One 8:e80216.
  3. Khasawneh AI, Laumaea A, Harrison DN, Bellamy-McIntyre AK, Drummer HE, Poumbourios P. 2013. Forced virus evolution reveals functional crosstalk between the disulfide bonded region and membrane proximal ectodomain region of HIV-1 gp41. Retrovirology 10:44.
  4. Drummer HE, Hill MK, Maerz AL, Wood S, Ramsland PA, Mak J, Poumbourios P. 2013. Allosteric modulation of the HIV-1 gp120-gp41 association site by adjacent gp120 variable region 1 (V1) N-glycans linked to neutralization sensitivity. PLoS Pathog 9:e1003218.
  5. McCaffrey K, Boo I, Tewierek K, Edmunds ML, Poumbourios P, Drummer HE. 2012. The role of conserved cysteine residues in Hepatitis C virus glycoprotein E2 folding and function. J Virol 86:3961-3974.
  6. Boo I, Tewierek K, Douam F, Lavillette D, Poumbourios P, Drummer HE. 2012. Distinct roles in folding, CD81 receptor binding and viral entry for conserved histidines of HCV glycoprotein E1 and E2. Biochem J 443:85-94.
  7. McCaffrey K, Gouklani H, Boo I, Poumbourios P, Drummer HE. 2011. The variable regions of hepatitis C virus glycoprotein E2 have an essential structural role in glycoprotein assembly and virion infectivity. J Gen Virol 92:112-121.
  8. Lay CS, Ludlow LE, Stapleton D, Bellamy-McIntyre AK, Ramsland PA, Drummer HE, Poumbourios P. 2011. Role for the terminal clasp of HIV-1 gp41 glycoprotein in the initiation of membrane fusion. J Biol Chem 286:41331-41343.
  9. Fraser J, Boo I, Poumbourios P, Drummer HE. 2011. Hepatitis C virus (HCV) envelope glycoproteins e1 and e2 contain reduced cysteine residues essential for virus entry. J Biol Chem 286:31984-31992.
  10. Drummer HE, McKeating JA. 2011. HCV receptors and entry inhibitors. In He S-LTaY (ed), Hepatitis C: Antiviral Drug Discovery and Development. Caister Academic Press.
  11. Bellamy-McIntyre AK, Bar S, Ludlow L, Drummer HE, Poumbourios P. 2010. Role for the disulfide-bonded region of human immunodeficiency virus type 1 gp41 in receptor-triggered activation of membrane fusion function. Biochem Biophys Res Commun 394:904-908.
  12. Aitken CK, Lewis J, Tracy SL, Spelman T, Bowden DS, Bharadwaj M, Drummer H, Hellard M. 2008. High incidence of hepatitis C virus reinfection in a cohort of injecting drug users. Hepatology 48:1746-1752.
  13. Wilson KA, Maerz AL, Bar S, Drummer HE, Poumbourios P. 2007. An N-terminal glycine-rich sequence contributes to retrovirus trimer of hairpins stability. Biochem Biophys Res Commun.
  14. Poumbourios P, Drummer HE. 2007. Recent advances in our understanding of receptor binding, viral fusion and cell entry of hepatitis C virus: new targets for the design of antiviral agents. Antivir Chem Chemother 18:169-189.
  15. McCaffrey K, Boo I, Poumbourios P, Drummer HE. 2007. Expression and characterization of a minimal hepatitis C virus glycoprotein E2 core domain that retains CD81 binding. J Virol 81:9584-9590.
  16. Bellamy-McIntyre AK, Lay CS, Baar S, Maerz AL, Talbo GH, Drummer HE, Poumbourios P. 2007. Functional links between the fusion peptide-proximal polar segment and membrane-proximal region of human immunodeficiency virus gp41 in distinct phases of membrane fusion. J Biol Chem 282:23104-23116.
  17. Drummer HE, Boo I, Maerz AL, Poumbourios P. 2006. A conserved Gly436-Trp-Leu-Ala-Gly-Leu-Phe-Tyr motif in hepatitis C virus glycoprotein E2 is a determinant of CD81 binding and viral entry. J Virol 80:7844-7853.
  18. Drummer HE, Poumbourios P. 2004. Hepatitis C virus glycoprotein E2 contains a membrane-proximal heptad repeat sequence that is essential for E1E2 glycoprotein heterodimerization and viral entry. J Biol Chem 279:30066-30072.
  19. Poumbourios P, Maerz AL, Drummer HE. 2003. Functional evolution of the HIV-1 envelope glycoprotein 120 association site of glycoprotein 41. J Biol Chem 278:42149-42160.
  20. Drummer HE, Maerz A, Poumbourios P. 2003. Cell surface expression of functional hepatitis C virus E1 and E2 glycoproteins. FEBS Lett 546:385-390.
  21. Drummer HE, Wilson KA, Poumbourios P. 2002. Identification of the hepatitis C virus e2 glycoprotein binding site on the large extracellular loop of CD81. J Virol 76:11143-11147.

Projects

Contact Details

Associate Professor Heidi E Drummer

Program Director, Disease Elimination; Co-Head, Drummer/Poumbourios Laboratory; Chair, Burnet Gender Equity Committee

Telephone

+61392822179

Email

heidi.drummer@burnet.edu.au