Methods of producing a pathogen with reduced replicative fitness are disclosed, as are attenuated pathogens produced using the methods. In particular examples, the method includes deoptimizing one or more codons in a coding sequence, thereby reducing the replicative fitness of the pathogen. Methods of using the attenuated pathogens as immunogenic compositions are also disclosed.

Methods of producing a pathogen with reduced replicative fitness are disclosed, as are attenuated pathogens produced using the methods. In particular examples, the method includes deoptimizing one or more codons in a coding sequence, thereby reducing the replicative fitness of the pathogen. Methods of using the attenuated pathogens as immunogenic compositions are also disclosed.

The invention relates to a genetically modified infectious measles virus derived from a live-attenuated measles virus strain, in which the gene encoding the viral accessory C protein has been knocked out (MV-deltaC). It concerns in particular the use of said genetically modified infectious MV-deltaC in the treatment of malignant tumour or cancer conditions, and for the preparation of agents or compositions for such treatment.

The invention relates to a genetically modified infectious measles virus derived from a live-attenuated measles virus strain, in which the gene encoding the viral accessory C protein has been knocked out (MV-deltaC). It concerns in particular the use of said genetically modified infectious MV-deltaC in the treatment of malignant tumor or cancer conditions, and for the preparation of agents or compositions for such treatment.