BpOmpW antigen administered with CAF01 adjuvant stimulates comparable T cell responses to Sigma adjuvant system

Abstract

There are no licensed vaccines to protect vulnerable populations from the potentially fatal tropical infection, melioidosis, despite its causative agent, Burkholderia pseudomallei, being endemic in tropical and subtropical regions. A promising vaccine candidate, BpOmpW protected mice from melioidosis infection for up to 81 days and stimulated robust interferon gamma responses in CD4+, CD8+, NK and NKT cells. In order to progress to human studies, selection of an adjuvant with an acceptable human safety profile that stimulates appropriate correlates of protection is essential. Here we demonstrate that the CAF01 vaccine adjuvant elicits optimal immune correlates of protection when administered with our BpOmpW vaccine. Specifically, we demonstrate that CAF01 administered with BpOmpW elicits robust Th1 responses, with potent IFN-γ responses in CD4+ and CD8+ T cells and NKT cells, in addition to Th17 and Th2 responses. This formulation will be particularly effective in protecting susceptible populations including people with type 2 diabetes from melioidosis.

Keywords

• Vaccine
• Adjuvant
• Melioidosis
• T cell responses
• Interferon γ
• Intracellular pathogen