title: Variation in the incidence of teratomas after the transplantation of nonhuman primate ES cells into immunodeficient mice.
abstract: Embryonic stem (ES) cells have the ability to generate teratomas when transplanted into immunodeficient mice, but conditions affecting the generation remain to be elucidated. Nonhuman primate cynomolgus ES cells were transplanted into immunodeficient mice under different conditions; the number of transplanted cells, physical state (clumps or single dissociated cells), transplant site, differentiation state, and immunological state of recipient mice were all varied. The tumorigenicity was then evaluated. When cynomolgus ES cells were transplanted as clumps into the lower limb muscle in either nonobese diabetic/severe combined immunodeficiency (NOD/SCID) or NOD/SCID/gammac(null) (NOG) mice, teratomas developed in all the animals transplanted with 1 x 10(5) or more cells, but were not observed in any mouse transplanted with 1 x 10(5) cells. However, when the cells were transplanted as dissociated cells, the number of cells necessary for teratomas to form in all mice increased to 5 x 10(5). When the clump cells were injected subcutaneously (instead of intramuscularly), the number also increased to 5 x 10(5). When cynomolgus ES cell-derived progenitor cells (1 x 10(6)), which included residual pluripotent cells, were transplanted into the lower limb muscle of NOG or NOD/SCID mice, the incidence of teratomas differed between the strains; teratomas developed in five of five NOG mice but in only two of five NOD/SCID mice. The incidence of teratomas varied substantially depending on the transplanted cells and recipient mice. Thus, considerable care must be taken as to tumorigenicity.
authors.affiliation: Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kishi
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shibata
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Nakamura
authors.forename: Koichi
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Shigeo
authors.initials: S
authors.lastname: Masuda
authors.forename: Tamako
authors.initials: T
authors.lastname: Ikeda
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Muramatsu
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hanazono
mesh_terms: D000818:Animals; D053595:Embryonic Stem Cells / Q000473:pathology / Q000637:transplantation*; D007273:Injections, Intramuscular; D007279:Injections, Subcutaneous; D008252:Macaca fascicularis; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D018482:Muscle, Skeletal; D033581:Stem Cell Transplantation / Q000009:adverse effects*; D013724:Teratoma / Q000209:etiology* / Q000473:pathology; D014183:Transplantation, Heterologous / Q000009:adverse effects*