Modification of viral surface proteins for redirecting coronavirus to tumor cells. Schematic representation of MHV surface glycoproteins spike (S) and hemagglutinin-esterase (HE) and of modifications applied to redirect the virus to novel target cell antigens. Modifications tested include: insertion of small peptide ligands, including RGD and NGR, and extension with the anti-EGFR scFv425. Recombinant MHV viruses encoding such mutated S proteins or modified HE proteins (in the presence of wild type spike proteins) were generated by targeted recombination [35]. Indicated is whether the intended recombinant viruses could actually be isolated (confirmed by RT-PCR and sequencing). Also indicated is the tropism of each successfully generated recombinant virus for murine and for human cells (Verheije and Rottier, unpublished data).