This study found a higher percentage of CD8+ T cells in piglets immunized with a CVC1302-adjuvanted inactivated foot-and-mouth disease virus (FMDV) vaccine. We wondered whether the CVC1302-adjuvanted inactivated FMDV vaccine promoted cellular immunity by promoting the antigen cross-presentation efficiency of ovalbumin (OVA) through dendritic cells (DCs), mainly via cytosolic pathways. This was demonstrated by the enhanced levels of lysosomal escape of OVA in the DCs loaded with OVA and CVC1302. The higher levels of ROS and significantly enhanced elevated lysosomal pH levels in the DCs facilitated the lysosomal escape of OVA. Significantly enhanced CTL activity levels was observed in the mice immunized with OVA-CVC1302. Overall, CVC1302 increased the cross-presentation of exogenous antigens and the cross-priming of CD8+ T cells by alkalizing the lysosomal pH and facilitating the lysosomal escape of antigens. These studies shed new light on the development of immunopotentiators to improve cellular immunity induced by vaccines.
