Development of chimeric hepatitis B virus like particles as a vaccine delivery platform for multiple HIV-1 epitopes [ 2004 - 2005 ]

Research Grant

Researchers: Prof Hans Netter (Principal investigator) ,  Dr Roderick Macfarlan

Brief description The small envelope protein of hepatitis B virus (HBsAg) can self-assemble into highly organised viruslike particles with about 150 HBsAg-proteins forming a virus-like particle (VLP). VLPs induce an effective immune response, mainly against the exposed major antigenic site, the hydrophilic ‘a’- determinant region. To create a novel HBsAg-specific vaccine vector, foreign epitopes were inserted into the major antigenic site allowing surface orientation of the inserted sequence. Pilot studies involving the vaccination of mice with VLPs containing an epitope derived from the AIDS-virus (human immunodeficiency virus 1, HIV-1) or various hepatitis C virus-specific epitopes resulted in high titre antibody responses. This project aims for the development of a multi-component vaccine targeting a non-structural HIV-1 protein and therefore, avoiding the selective pressure directed against the structural proteins. The non-structural HIV-1 tat-protein is a multi-functional protein with an extracellular mode to sensitise uninfected cells for HIV-1 infection and to reactivate HIV-1 from quiescently infected cells. The use of eight tat-sequences is sufficient to provide coverage against 99% of HIV-1 sequences. We will develop hybrid particles that are composed of different sets of chimeric HBsAg proteins each containing a distinct tat-epitope. With this application, we aim to develop hybrid particles for the delivery of the complete set of tat-epitopes. The hybrid particles will be used for vaccination studies in mice, and the antibodies assessed by an in-vitro assay. This will lead to the development of a therapeutic and-or prophylactic HIV-1 vaccine, which could be used either for mass immunisation or in support of combination drug therapy and would have all the cost and production advantages of the widely used hepatitis B vaccine.

Funding Amount $AUD 139,500.00

Funding Scheme NHMRC Development Grants

Notes Development Grant