Optimized production of virus-like particles in a high-CHO-cell-density transient gene expression system for foot-and-mouth disease vaccine development

Background/Objectives: Foot-and-mouth disease virus (FMDV) poses a continuous threat to livestock health and agricultural economies. Current vaccines require high biosafety standards and are costly to produce. While novel vaccine technologies have been explored, most fail to meet industrial scalability, cost-efficiency, or multiserotype flexibility required for effective FMD control. This study aimed to evaluate the feasibility of using a high-cell density transient gene expression (TGE) system in CHO cells for the production of FMDV virus-like particles (VLPs) as a recombinant vaccine platform. Methods: VLP expression was optimized by adjusting cDNA and polyethyleneimine (PEI) concentrations. Expression yields were compared at 24 and 48 h post-transfection to determine optimal harvest timing. We further tested the system’s capacity to express different serotypes and chimeric constructs, incorporating VP1 sequences from various FMDV strains. Immunogenicity was evaluated in swine using VLPs from the A2001 Argentina strain as a model. Results: Optimal VLP expression was achieved at 24 h post-transfection. Chimeric constructs incorporating heterologous VP1 regions were successfully expressed. Immunized pigs developed protective antibody titers as measured by a virus neutralization test (VNT, log10 titer 1.43) and liquid-phase blocking ELISA (LPBE, titer 2.20) at 28 days post-vaccination (dpv). Titers remained above protective thresholds up to 60 dpv with a single dose. A booster at 28 dpv further elevated titers to levels comparable to those induced by the inactivated vaccine. Conclusions: Our results demonstrate the feasibility of using CHO cell-based TGE for producing immunogenic FMDV VLPs. This platform shows promise for scalable, cost-effective, and biosafe development of recombinant FMD vaccines.

Instituto de Virología

Fil: Mignaqui, Ana Clara. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas. INCUINTA; Argentina

Fil: Mignaqui, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; Argentina

Fil: Mignaqui, Ana Clara. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; Argentina

Fil: Ferella, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas. INCUINTA; Argentina

Fil: Ferella, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Sánchez, Cintia. Biogénesis Bagó; Argentina

Fil: Stuible, Matthew. National Research Council Canada. Human Health Therapeutics Research Center; Canadá

Fil: Scian, Romina. Biogénesis Bagó; Argentina

Fil: Filippi, Jorge. Biogénesis Bagó; Argentina

Fil: Cardillo, Sabrina Beatriz. Biogénesis Bagó; Argentina

Fil: Durocher, Yves. National Research Council Canada. Human Health Therapeutics Research Center; Canadá

Fil: Wigdorovitz, Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas. INCUINTA; Argentina

Fil: Wigdorovitz, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina