An objective of the present invention is to provide vectors for conveniently and efficiently producing ES-like cells in which foreign genes are not integrated into the chromosome. The present inventors discovered methods for producing ES-like cells from somatic cells using chromosomally non-integrating viral vectors. Since no foreign gene is integrated into the chromosome of the produced ES-like cells, they are advantageous in tests and research, and immunological rejection and ethical problems can be avoided in disease treatments.

An objective of the present invention is to provide vectors for conveniently and efficiently producing ES-like cells in which foreign genes are not integrated into the chromosome. The present inventors discovered methods for producing ES-like cells from somatic cells using chromosomally non-integrating viral vectors. Since no foreign gene is integrated into the chromosome of the produced ES-like cells, they are advantageous in tests and research, and immunological rejection and ethical problems can be avoided in disease treatments.

Described herein are methyltransferase (MTase)-defective recombinant viruses as vaccines for human metapneumovirus (hMPV), human respiratory syncytial virus (hRSV), and human parainfluenza virus type 3 (PIV3); as well as related materials and methods.

The present invention includes methyltransferase (MTase)-defective recombinant viruses as live vaccine candidates for human metapneumovirus (hMPV), human respiratory syncytial virus (hRSV), and human parainfluenza virus type 3 (PIV3). Here the inventors provide the technical description for generating MTase-defective paramyxoviruses useful as immunogens, as well as related materials and methods.