Immune Dysregulation In HIV Patients With Immune Reconstitution After Highly Active Anti-retroviral Therapy
Funder
National Health and Medical Research Council
Funding Amount
$411,000.00
Summary
As HIV infection progresses to AIDS, there is a depletion of CD4 T-cells from the patient's blood and inhibition of the function of the remaining cells. Some immune defects resolve if the patient is given treatment with highly active anti-retroviral therapy (HAART), but it remains to be determined if the function of the imune system returns fully to normal. We have shown that problems with the regulation of the restored immune system in the first 6 months of treatment can lead to diseases associ ....As HIV infection progresses to AIDS, there is a depletion of CD4 T-cells from the patient's blood and inhibition of the function of the remaining cells. Some immune defects resolve if the patient is given treatment with highly active anti-retroviral therapy (HAART), but it remains to be determined if the function of the imune system returns fully to normal. We have shown that problems with the regulation of the restored immune system in the first 6 months of treatment can lead to diseases associated with Mycobacterial infections (eg: tuberculosis), CMV retinitis, hepatitis B virus or hepatitis C virus. We have defined these conditions as Immune Restoration diseases (IRD) and shown that they occur in one in four individuals who begin HAART from low baseline CD4 T-cell counts. IRD are likely to become common as therapy becomes available in Africa and Asia as patients begin treatment from low CD4 T-cell counts. There is also emerging evidence that dysregulated T-cell responses may cause disease later in the course of immune reconstitution. For example, some patients with undetectable HIV experience opportunistic infections or autoimmune disease after many months of HAART. This project will use West Australian patients receiving optimal therapy for their HIV infection. We will analyse immune activation and T-cell function in patients beginning HAART with low CD4 T-cell counts and patients who have had well-controlled HIV infection for at least 6 months. Blood samples will be collected for the measurement of immunological messengers (cytokines) known to be involved in different types of immune responses. The results will be correlated with the clinical outcome.Read moreRead less
Though vaccination has had a major impact on the number of persons becoming infected, chronic infection with the hepatitis B virus (HBV) still remains a major worldwide problem, with 350 million people chronically infected. The existence of HBV vaccine escape mutants and the fact that 5% of vaccinees fail to respond implies that HBV will remain a significant public health problem for the foreseeable future. Current treatments for chronic HBV infection have a low success rate (~20%) and patients ....Though vaccination has had a major impact on the number of persons becoming infected, chronic infection with the hepatitis B virus (HBV) still remains a major worldwide problem, with 350 million people chronically infected. The existence of HBV vaccine escape mutants and the fact that 5% of vaccinees fail to respond implies that HBV will remain a significant public health problem for the foreseeable future. Current treatments for chronic HBV infection have a low success rate (~20%) and patients with chronic infection are expected to die prematurely due to chronic liver disease or primary liver cancer. Interestingly, exposure to HBV can lead to either acute resolving or chronic HBV infection. Like chronic infections, acute infections involve spread of virus to virtually every hepatocyte, followed by rapid clearance of the virus mediated by the host immune response. Our immediate aim is to study the resolution of acute HBV infections to determine how the stable intracellular viral genome, covalently closed circular DNA (cccDNA), is cleared from the nucleus of infected hepatocytes. Our broad long-term aim is to develop new and effective treatments for chronic HBV infection based on a better understanding of how acute HBV infections are resolved by the host. Based on our previous work we believe that clearance of cccDNA requires hepatocyte death, together with compensatory proliferation of other infected hepatocytes. We will perform detailed studies in duck hepatitis B virus (DHBV) infected ducks to determine if hepatocyte death and compensatory proliferation are essential to clear the infection, or if mechanisms exist for clearance that do not involve cell destruction.Read moreRead less
Processes Underlying Establishment And Maintenance Of The Latent HIV Resevoir And Potential Impact Of Integrase Inhibitors
Funder
National Health and Medical Research Council
Funding Amount
$318,044.00
Summary
Therapy for HIV-infected individuals is currently able to control the growth of the virus, but cannot eradicate the viral infection. This is due to a pool of CD4+ T lymphocytes which contain HIV DNA in a latent state, ready to reactivate as soon as therapy is interrupted. This project aims to better understand how this pool of latently infected CD4+ T lymphocytes is established and maintained, particularly how it is linked to the essential T cell survival signal from interleukin 7.
Comparative Effectiveness Of Vaccine-induced SIV-specific CD8 T Cells
Funder
National Health and Medical Research Council
Funding Amount
$607,797.00
Summary
A HIV vaccine remains elusive. Although killer T cell immunity can provide partial protection from HIV disease, we don't know the best type of killer T cells to induce by vaccination. This project compares multiple HIV vaccine strategies in macaques. We will carefully study the quality of killer T cell immunity induced using novel and cutting-edge assays. We will identify the requirements for effective killer T cell immunity to HIV.
Gamma-ray Inactivated Influenza A Virus Vaccine For Cross-protective T Cell Immunity
Funder
National Health and Medical Research Council
Funding Amount
$239,963.00
Summary
Although there are new antiviral drugs that appear to be effective against influenza virus, the far more costeffective and efficient means to combat an influenza pandemic would be by vaccination. Current influenza vaccines employ virus preparations that are inactivated by chemical treatment. The inactivated vaccines, which function mostly by inducing antibody against the virus, have to be reformulated almost every year to take account of the changing virus because the antibodies recognize the vi ....Although there are new antiviral drugs that appear to be effective against influenza virus, the far more costeffective and efficient means to combat an influenza pandemic would be by vaccination. Current influenza vaccines employ virus preparations that are inactivated by chemical treatment. The inactivated vaccines, which function mostly by inducing antibody against the virus, have to be reformulated almost every year to take account of the changing virus because the antibodies recognize the viral surface which is prone to mutation. Accordingly, in terms of the threatening H5N1 avian influenza pandemic, it is not known if an inactivated vaccine based on the circulating H5N1 strain will be effective if the virus mutates to adapt to efficient growth and spread in the human population. In contrast to the antibody response against influenza virus, the cytotoxic T cell response is broadly crossreactive between heterologous influenza virus strains. Live virus infection efficiently induces cytotoxic T cell immunity which plays an important role in reducing disease severity and mortality following infection with a second, heterologous influenza virus, although infection per se is not prevented. Accordingly, vaccination strategies that elicit cytotoxic T cell memory should be given urgent consideration in the preparation against an influenza pandemic. We have found that the use of gamma-irradiation (in contrast to chemical treatment) for the preparation of inactivated experimental vaccines against influenza and other viruses does not destroy the ability of the vaccines to elicit cytotoxic T cell immunity. The gamma-ray inactivated vaccines conferred protection against lethal challenge with heterologous influenza virus strains in mice. This proposal is aimed at extending this novel finding to avian influenza viruses and to uncover the mechanisms involved in the cytotoxic T cell immunogenicity of gamma-ray inactivated vaccines.Read moreRead less
Understanding The Importance Of Panton-Valentine Leukocidin Production In Australian Isolates Of Staphylococcus Aureus.
Funder
National Health and Medical Research Council
Funding Amount
$118,796.00
Summary
New strains of the superbug methicillin-resistant Staphylococcus aureus (MRSA) have emerged in the community, causing severe, sometimes fatal infections in otherwise healthy people. These strains, called community-acquired MRSA produce a toxin (Panton-Valentine leukocidin). This project will provide important information about how this toxin promotes disease, and how the immune system responds to the toxin, providing the basis for the development of immunotherapies against this new superbug.