ISPA cage-like particle adjuvant enhances protection induced by A/Arg/2001 Foot and Mouth Disease Virus-Like Particles

Le résumé fourni par la source

Foot-and-Mouth Disease Virus (FMDV) causes an acute disease with important economy losses worldwide. Currently available vaccines are based on inactivated FMDV and oil-adjuvants. The use of Virus-Like Particles (VLPs) for subunit vaccines has been reported to be promising since it avoids the biological hazard of using virus in vaccine production while conserving conformational viral epitopes. However, a more efficient and cost-effective adjuvant than those currently used is needed. Immunostimulant-Particle Adjuvant (ISPA) is an Immune Stimulating Complex (ISCOM) - type adjuvant formulated with dipalmitoyl-phosphatidylcholine, cholesterol, stearylamine, alpha tocopherol and QuilA. In the present work, we have evaluated the immune response against FMDV using VLPs and ISPA as adjuvant. VLPs (serotype A/Arg/01) were obtained by transient gene expression in mammalian cell cultures, and a previously developed murine model, able to predict the ability of a vaccine to induce protection in cattle, was used for vaccination experiments in a first approach. The VLPs-ISPA vaccine induced protection in mice against challenge and elicited a specific antibody response in sera. In a second approach, the VLPs-ISPA vaccine was tested in calves. Interestingly one vaccine dose was enough to induce total α-FMDV antibodies , as measured by ELISA, as well as neutralizing Abs. Antibody titers reached an Expected Percentage of Protection higher than 90%. The EPP index calculates the probability that livestock will be protected against a challenge of 10.000 bovine infectious doses after vaccination. Moreover, IFN-γ levels secreted in vitro by mononuclear cells of VLP-ISPA vaccinated animals were significantly higher (p <0.05) than in the non-adjuvanted VLPs group. Overall, the results demonstrate that VLPs and ISPA are a promising combination for the development of a novel FMD vaccine, since no infectious FMDV is used and a protective immune response can be induced in calves, comparable to that achieved with the commercial FMDV vaccine.

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