Development of A HTLV-1 Vaccine

PROJECT SUMMARY For this proposal we intend to develop a novel vaccine to prevent and possibly treat Human T cell leukemia virus type-1 (HTLV-1) associated diseases. HTLV-1 is a human retrovirus that is the causative agent of a malignant T CD4+ cell lymphoproliferation referred to as Adult T cell leukemia/lymphoma (ATLL), as well as

several inflammatory disorders with the most problematic being human myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 infection is endemic in many areas around the world including southern Japan, the southern United States, central Australia, the Caribbean, South America, equatorial Africa, and the middle East. Over 10

million people may be infected worldwide. It is estimated that approximately 5% of HTLV-1 positive individuals will develop ATL, and 2% HAM/TSP. Seropositive rates in certain areas reach 20–40% among people aged over 50-years. With millions affected worldwide, HTLV-1 is a major problem in endemic communities and remarkably,

there are no effective vaccine or treatment options to prevent ATL or HAM/TSP afflicted individuals. Given this, aim to develop and test the efficacy of a novel vaccine to prevent HTLV1-mediated disease. Aim 1: To evaluate the immunogenicity, in immunocompetent murine models, including mice with a humanized

immune system (NSG™-SGM3) VSV-based vaccine vectors that express the HTLV-1 glycoprotein and regulatory proteins TAX and HBZ (VSV-gp62-∆HT). The ability of our candidate vaccine to generate neutralizing antibodies to the glycoprotein will be analyzed, as well as the production of cytotoxic T cells (CTLs) to gp62, TAX

and HBZ. Aim 2: We aim to compare whether our vaccine can be used to prevent HTLV-1 transformation associated disease. This approach will include establishing whether VSV-gp62-∆HT can prevent the establishment of HTLV- 1-assocated leukemia/lymphoma in NSG™-SGM3 mice. Our objectives are to collate sufficient information to

warrant the consideration of a variety of Phase I trials to prevent HTLV-1 -associated disease.