Fig. 1.

Targeting, arming, and stealthing of oncolytic MeV. a) Targeting and tumor-specificity of oncolytic MeV can be engineered on multiple levels. Entry targeting: Shown here is a fully-retargeted MeV that recognizes tumor antigens via scFv fused to the MeV H protein. Post-entry targeting: Displayed is an oncolytic MeV carrying target sites for microRNAs which are present in healthy cells but lost in malignant cells. This microRNA-controlled MeV is strongly attenuated in healthy cells expressing cognate microRNAs, but remains fully effective against tumor cells. b) Oncolytic MeV can be engineered to encode therapeutic transgenes. c) Stealthing of oncolytic MeV. Left: Pseudotyping of MeV with the envelope glycoproteins of a closely related paramyxovirus (canine distemper virus, CDV). Right: To avoid neutralization by pre-existing anti-MeV antibodies, it is possible to shield the individual virions using a polymeric envelope structure.