DOI: 10.1126/science.1133542 , 482 (2007); 315Science et al.Kitai Kim,ParthenogenesisHistocompatible Embryonic Stem Cells by www.sciencemag.org (this information is current as of September 27, 2007 ):The following resources related to this article are available online at http://www.sciencemag.org/cgi/content/full/315/5811/482version of this article at: including high-resolution figures, can be found in the onlineUpdated information and services, http://www.sciencemag.org/cgi/content/full/1133542/DC1 can be found at: Supporting Online Material http://www.sciencemag.org/cgi/content/full/315/5811/482#otherarticles, 10 of which can be accessed for free: cites 21 articlesThis article 2 article(s) on the ISI Web of Science. cited byThis article has been http://www.sciencemag.org/cgi/collection/developmentDevelopment : subject collectionsThis article appears in the following http://www.sciencemag.org/about/permissions.dtl in whole or in part can be found at: this articlepermission to reproduce of this article or about obtaining reprintsInformation about obtaining registered trademark of AAAS. is aScience2007 by the American Association for the Advancement of Science; all rights reserved. The title CopyrightAmerican Association for the Advancement of Science, 1200 New York Avenue NW, Washington, DC 20005. (print ISSN 0036-8075; online ISSN 1095-9203) is published weekly, except the last week in December, by theScience on September 27, 2007 www.sciencemag.orgDownloaded fromHistocompatible EmbryonicStem Cells by ParthenogenesisKitai Kim,1,2,4Paul Lerou,1,4,5Akiko Yabuuchi,1,2,4Claudia Lengerke,1,2,4Kitwa Ng,1,2,4Jason West,1,2,4Andrew Kirby,6Mark J. Daly,6George Q. Daley1,2,3,4*Genetically matched pluripotent embryonic stem (ES) cells generated via nuclear transfer orparthenogenesis (pES cells) are a potential source of histocompatible cells and tissues fortransplantation. After parthenogenetic activation of murine oocytes and interruption of meiosis I orII, we isolated and genotyped pES cells and characterized those that carried the full complement ofmajor histocompatibility complex (MHC) antigens of the oocyte donor. Differentiated tissues fromthese pES cells engrafted in immunocompetent MHC-matched mouse recipients, demonstratingthat selected pES cells can serve as a source of histocompatible tissues for transplantation.Parthenogenesis entails the development ofan embryo directly from an oocyte with-out fertilization. Many animal and plantspecies reproduce via p arthenogenesis, but inmice, parthenogenetic embryos develop only tothe early limb bud stage because mammalianembryonic development requires gene expres-sion from the paternal genome. Parthenogeneticembryonic stem (pES) cells have been isolatedfrom parthenogenetic blastocysts of mice andprimates (1, 2). Both mouse and primate pEScells undergo extensive differentiation in vitro(2, 3), and pES cells contribute widely to adulttissues in chimeric mice (1). A human case ofparthenogenetic chimerism has been described inwhich the hematopoietic system and skin werederived from parthenogenetic cells (4). In additionto pluripotent stem cells from fertilized embryosand embryos create d by somatic-cell nuclear trans-fer (5), parthenogenesis is another method forcreating pluripotent stem cells that might serveas a source of tissue for transplantation.Highly efficient methods of experimentalmurine parthenogenesis exist in which oocytesarrested at the second meiotic metaphase (MII)are chemically activated in the presence of cy-tochalasin, a drug that prevents extrusion of thesecond polar body (6). Diploidy is maintained,and the resulting pseudozygote can developinto a blastocyst from which ES cells can beisolated [which we term p(MII)ES cells (7)].In some cases, pES cells harbor a duplication ofa haploid genome and are thus believed to bepredominantly homozygous (7, 8). Becausetissues derived from homozygous pES cellswould express only one of two sets of parentalhistocompatibility antigens, they can be morereadily matched to patients and might pose lessrisk of tissue rejection ( 9). However, in hetero-zygous recipients, major histocompatibility com-plex (MHC) homozygous tissues may be rejectedby natural killer (NK) cells that recognize thelack of one set of histocompatibility antigens, aphenomenon called “hybrid resistance” that isparticularly relevant to bone marrow transplanta-tion (10). As compared with mismatched org ans,partial MHC antigen matching enhances allograftsurvival, but full MHC-matched tissues are themost favorable for transplant (11 ). The only cer-tain strategy for avoiding immunologic complica-tions is to transplant genetically identical tissues,but this limits transplantation to autologous tis-sues, transplants between monozygotic twins, orcells created by somatic cell nuclear transfer .Here we characterize pluripotent ES cell linesgenerated by parthenogenesis in which both ofthe maternal MHC loci have been maintained.Differentiated tissues from such MHC-matchedES cells can be transplanted into the oocyte do-nor strain without rejection, suggesting that thesecells could be a favorable source of histocom-patible tissues for transplantation.Recombinant MHC-matched p(MII)ES cells.We reasoned that during the isolation of p(MII)EScells from hybrid F1mice, recombination eventsoccurring between paired homologous chro-mosomes in meiosis I would produce cells thathad restored heterozygosity at the MHC loci(Fig. 1B). Recombination frequencies place themurine H-2 MHC locus at ~18.5 centimorgans(cM) from the centromere on mouse chromosome17 (12), thus predicting that approximately oneRESEARCH ARTICLE1Division of Pediatric Hematology/Oncology, Children’sHospital Boston and Dana Farber Cancer Institute, Boston,MA 02115, USA.2Department of Biological Chemistry andMolecular Pharmacology, Harvard Medical School, Boston,MA 02115, USA.3Division of Hematology, Brigham andWomen’s Hospital, Boston, MA 02115, USA.4Harvard StemCell Institute, Cambridge, MA 02138, USA.5Division ofNewborn Medicine, Brigham and Wome n’s Hospital andChildren’s Hospital, Harvard Medical School, Boston, MA02115, USA.6Center for Human G enetic R esearch,Massachusetts General Hospital, Boston, MA 02115, USA.*To whom correspondence should be addressed. E-mail:[email protected] PBAB4n (GV) 2n (MI) 1n (MII) 2nCCDNo1st PBmitotic cleavageCCCBchemical activation0h 6h