Abstract: Provided is a method for producing naive induced pluripotent stem cells from human somatic cells, comprising the following steps (1) to (3): (1) introducing one or more vectors containing a reprogramming factor into human somatic cells, (2) culturing said somatic cells in the presence of a naive medium, and (3) after step (2), culturing the resulting cells in the presence of the naive medium under the condition in which the amount of the vectors per the somatic cell is reduced to 30% or less of that at the start of step 3.

Abstract: An objective of the present invention is to provide an improved negative-strand RNA viral vector and a use thereof, the negative-strand RNA viral vector exhibiting transient high expression of genes loaded in the vector and enabling the rapid removal of the vector after said expression. It was discovered that by adding a micro-RNA target sequence to the NP, P, or L gene of a negative-strand RNA viral vector, it is possible to control the expression of the vector depending on the micro-RNA expressed by the introduction cell. In particular, when a micro-RNA target sequence was added to the NP or P gene, the expression of the vector decreased depending on the micro-RNA, and the removal of the vector was promoted, while the effect was reversed when a micro-RNA target sequence was added to the L gene. The vector can be applied in cell therapy and regenerative medicine and can be used as a therapeutic vector that targets cancer.