Proteinaceous vaccines can range from plant viruses (top left), mammalian viruses (top right), bacteriophages (bottom left), to protein cages (bottom right). All the viruses other than the mammalian viruses are drawn to scale with one another while the two mammalian viruses are drawn to scale to each other. All biological units were drawn on Chimera. CPMV = cowpea mosaic virus (PDB ID: 1NY7), CCMV = cowpea chlorotic mottle virus (PDB ID: 1ZA7), adenovirus (PDB ID: 6CGV), herpes simplex virus-1 (PDB ID: 6CGR), Qβ (PDB ID: 1QBE), MS2 (PDB ID: 2MS2), ferritin (PDB ID: 2HFA), E2 (PDB ID: 6H5).