Adjuvanted Fusion Protein Vaccine Induces Durable Immunity to in Mice and Non-Human Primates.

Onchocerciasis remains a debilitating neglected tropical disease. Due to the many challenges of current control methods, an effective vaccine against the causative agent is urgently needed. Mice and cynomolgus macaque non-human primates (NHPs) were immunized with a vaccine consisting of a fusion of two protein antigens, -103 and -RAL-2 (-FUS-1), and three different adjuvants: Advax-CpG, alum, and AlT4. All vaccine formulations induced high antigen-specific IgG titers in both mice and NHPs. Challenging mice with L3 contained within subcutaneous diffusion chambers demonstrated that -FUS-1/Advax-CpG-immunized animals developed protective immunity, durable for at least 11 weeks. Passive transfer of sera, collected at several time points, from both mice and NHPs immunized with -FUS-1/Advax-CpG transferred protection to naïve mice. These results demonstrate that -FUS-1 with the adjuvant Advax-CpG induces durable protective immunity against in mice and NHPs that is mediated by vaccine-induced humoral factors.