Figure 1.

Primary immunological mechanisms of virus vectored-, VLP-, and VLV-induced antigen presentation. The top panel depicts a virus vectored vaccine that encodes an intracellular or non-secreted antigen. The principle manner of antigen presentation is via MHC class I presentation to CD8⁺ T cells through the direct presentation pathway. The middle panel depicts a classical ex vivo purified and injected VLP vaccine, which can be taken up by antigen-presenting cells to be presented on MHC class II and stimulate CD4⁺ T cells, and directly stimulates B cells with antigen in the form of VLPs. The bottom panel depicts a VLV, where the antigen is initially synthesized intracellularly for MHC class I presentation, followed by the release of VLPs, which stimulate CD4⁺ T cells and B cells, as in the middle panel.