METHODS FOR ENHANCING INFECTIVITY OF RETROVIRUSES
The present invention provides methods for producing retroviruses or viral vectors with enhanced infectivity. The methods entail transfecting a retroviral vector into a packaging cell that has suppressed expression or inhibited enzymatic activity of a parvulin prolyl peptidyl isomerase (parvulin PPIase), and culturing the transfected packaging cell to allow production of viral particles. The invention also provides methods for enhancing efficiency of gene transfer with a recombinant retrovirus. These methods involve constructing a recombinant retroviral vector expressing a target gene, transfecting into a packaging cell that has suppressed expression or inhibited enzymatic activity of a parvulin prolyl peptidyl isomerase (parvulin PPIase), culturing the transfected packaging cell to allow production of recombinant retroviral particles, harvesting recombinant retroviral particles from supernatant of the cultured cell, and transducing the recombinant retroviral particles into a target cell. Kits for carrying out these methods are also provided in the invention.