A vector capable of transducing non-dividing and/or slowly dividing cells is provided, wherein the vector is a lentiviral LTR-deleted vector. Also provided is a method for producing a protein of interest in a non-dividing or slowly dividing cell by transducing the cell with a lentiviral LTR-deleted vector and expressing the protein of interest in the cell. In addition, target cells containing the lentiviral LTR-deleted vector are provided.