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Preimplantation Human Embryos and Embryonic Stem Cells Show Comparable Expression of Stage-Specific Embryonic Antigens

^a Section of Reproductive Biology, The School of Medicine and Biomedical Science and
^b Department of Biomedical Science, University of Sheffield, Sheffield, UK;
^c Care Ltd, The Park Hospital, Arnold, Nottingham, UK;
^d Wisconsin Regional Primate Research Center and Department of Anatomy, School of Medicine, University of Wisconsin, Madison, WI, USA

Key Words. Human embryos • Embryonic stem cells • Differentiation • Cell surface markers

Correspondence: Peter W. Andrews, Ph.D., Department of Biomedical Sciences, University of Sheffield, S10 2TN, Sheffield, UK. Telephone: 44-0-114-222-4173; Fax: 44-0-114-222-2399; e-mail: p.w.andrews{at}sheffield.ac.uk

	ABSTRACT

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Cell-surface antigens provide invaluable tools for the identification of cells and for the analysis of cell differentiation. In particular, stage-specific embryonic antigens that are developmentally regulated during early embryogenesis are widely used as markers to monitor the differentiation of both mouse and human embryonic stem (ES) cells and their malignant counterparts, embryonic carcinoma (EC) cells. However, there are notable differences in the expression patterns of some such markers between human and mouse ES/EC cells, and hitherto it has been unclear whether this indicates significant differences between human and mouse embryos, or whether ES/EC cells correspond to distinct cell types within the early embryos of each species. We now show that human ES cells are characterized by the expression of the cell-surface antigens, SSEA3, SSEA4, TRA-1-60, and TRA-1-81, and by the lack of SSEA1, and that inner cell mass cells of the human blastocyst express a similar antigen profile, in contrast to the corresponding cells of the mouse embryo.

	INTRODUCTION

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Permanent lines of pluripotent embryonic stem (ES) cells have now been established in culture from explanted human blastocysts [1,2]. They are able to differentiate into a wide range of cell types in vitro and form teratomas in immunosuppressed mice. They also share some features in common with murine embryos and ES cells, for example, high-level expression of alkaline phosphatase and the stem cell transcription factor, Oct4. Nevertheless, these human ES (hES) cells also exhibit marked differences from their murine counterparts, particularly with respect to their expression of several stage-specific embryonic antigens (SSEA). Such differences from the mouse have also been noted before in the case of human embryonal carcinoma (EC) cells, the stem cells of teratocarcinomas and the presumed malignant counterparts of embryo-derived ES cells [3–6].

Murine ES cells closely resemble cells of the late inner cell mass (ICM) of the blastocyst in their cell-surface antigen phenotype: SSEA1, a carbohydrate antigen, also known as Le^x, is a fucosylated derivative of type 2 polylactosamine and appears during late cleavage stages of mouse embryos [7,8]. It is strongly expressed by murine ICM and ES cells, as well as cells of the trophectoderm; it is absent from the primitive endoderm. Two other glycolipid antigens with globoseries carbohydrate core structures, SSEA3 and SSEA4, are expressed by unfertilized eggs and early cleavage embryos, but disappear by the blastocyst stage and are not expressed by cells of the ICM; these antigens are expressed by the primitive endoderm [9,10]. Likewise, murine ES cells also do not express either SSEA3 or SSEA4. In culture, the differentiation of murine EC and ES cells is typically characterized by the loss of SSEA1 expression and may be accompanied, in some instances, by the appearance of SSEA3 and SSEA4 [11,12].

By contrast, human EC cells typically express SSEA3 and SSEA4 but not SSEA1, while their differentiation is characterized by the downregulation of SSEA3 and SSEA4 and upregulation of SSEA1 [13,14]. The initial reports of hES cell lines have indicated that they too express SSEA3 and SSEA4 [1,2], as well as the keratan sulphate-associated antigens, TRA-1-60 and TRA-1-81, that are also characteristic of human EC cells [15,16]. So far, however, no direct comparison has been made between the surface-antigen phenotype of hES or EC cell lines and the embryonic cells to which they are thought to correspond within the human blastocyst. Thus, hitherto, it has been unclear whether these marked differences in surface-antigen expression indicate significant differences between human and mouse embryos, or whether ES/EC cells correspond to distinct cell types within the early embryos of each species.

We have now shown that hES cells in culture and the ICM cells from human blastocysts share expression of SSEA3, SSEA4, TRA-1-60, and TRA-1-81 and do not express SSEA1. These observations suggest that ES and EC cells do resemble ICM cells in humans as well as in the mouse, and that the differences between human and mouse ES/EC cells reflect differences between human and mouse embryos.

	MATERIALS AND METHODS

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Cell Culture
The hES cell lines, H7 and H14 [1], were cultured in Knockout-Dulbecco's modified Eagle's medium (GIBCO-BRL; Grand Island, NY; http://www.invitrogen.com) supplemented by 20% "serum replacement, SR" (GIBCO-BRL) on mouse embryo fibroblast feeder cells that had been inactivated by treatment with mitomycin C under a humidified atmosphere of 5% CO₂ in air. For subcultivation, the cells were harvested by treatment with 1 mg/ml collagenase IV and dispersed by scraping, to maintain the cells in small clumps. Differentiation was induced by incorporating all-trans-retinoic acid (Eastman-Kodak; Rochester, NY; http://www.kodak.com) (10^-5 M) into the medium as described for human EC cells [13].

Surface-Antigen Expression
Cell-surface-antigen expression of cultured cells was assessed by indirect immunofluorescence detected by flow cytofluorimetry after harvesting the cultures as single-cell suspensions using trypsin-EDTA, as described previously [14,17]. The following primary monoclonal antibodies were used to detect surface-antigen expression: MC631 (anti-SSEA3) [9], MC813-70 (anti-SSEA4) [10], MC480 (anti-SSEA1) [7], TRA-1-60 [15], TRA-1-81 [15], TRA-2-54 (anti-liver/kidney/bone alkaline phosphatase) [18], TRA-1-85 (anti-Ok(a)) [19], and anti-Thy1 [20]. Fluorescein isothiocyanate (FITC)-labeled goat anti-mouse IgM or anti-IgG was used as the secondary antibody, as appropriate to the isotype of the primary antibody. In some experiments, cells that were either positive or negative for SSEA3 and SSEA1 were isolated by fluorescence-activated cell sorting [17].

Surface-Antigen Expression by Preimplantation Embryos
Under license from the Human Fertilisation and Embryology Authority (HFEA) and with local ethical approval, frozen-thawed human embryos (n = 52), surplus to clinical needs, were obtained with fully informed consent from patients undergoing assisted conception treatment. Mouse embryos were recovered from superovulated and naturally mated Swiss mice. All embryos were fixed in 4% paraformaldehyde in phosphate-buffered saline (PBS) for 1 hour and washed twice in PBS. Blastocysts were permeabilized with 0.005% triton X-100 for 15 minutes and were washed twice in PBS. Incubations with primary and secondary (anti-mouse FITC-conjugated IgG or IgM) antibodies were for 1 hour, and embryos were mounted in mowiol/Dabco antifade solution before examination by epifluorescent microscopy.

RT-PCR Analysis of Gene Expression
Total RNA was extracted from ES cells, sorted for antigen expression using Tri Reagent (Sigma; Poole, Dorset, UK; http://www.sigmaaldrich.com), and treated with DNase (DNA-Free; Ambion; Austin, TX; http://www.ambion.com). Subsequently, no genomic contamination could be detected by polymerase chain reaction (PCR) (data not shown). One microgram of total RNA was used for each reverse transcription (RT)-PCR reaction as previously described [21]. Equal aliquots of RT product were then subjected to PCR using the primers and conditions summarized in Table 1. In all cases, 35 PCR cycles were used, except for Oct4 (28 cycles), Rex-1 (30 cycles), and ß-actin (20 cycles). The PCR primers for alpha-fetoprotein (AFP) were those reported by Schuldiner et al. [22]; those for NeuroD1 (ND-1) and ß-actin were reported by Duran et al. [21]. The remaining primers were designed by using the PRIMERSELECT package from the DNASTAR suite of programs, and the specificity of the RT-PCR products was confirmed by sequencing.

	RESULTS

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To confirm the initial reports of surface-antigen expression patterns of hES cells [1,2], we examined the two hES cell lines, H7 and H14. As anticipated, many cells in these cultures strongly expressed all four of the antigens, SSEA3, SSEA4, TRA-1-60, and TRA-1-81. They also expressed the liver/bone/kidney isozyme of alkaline phosphatase, detected by antibody TRA-2-54 [18], and human Thy1 [20] (Fig. 1). Murine EC and ES cells also strongly express alkaline phosphatase [25], but they do not express Thy1 [26], although human EC cells are Thy1⁺ [27]. This expression pattern was repeatedly observed in several assays carried out on cultures maintained by serial passaging over 6 months. When H14 hES cells were cultured in the presence of retinoic acid, marked downregulation of these antigens was seen, consistent with differentiation that is also seen with some human EC cell lines following exposure to retinoic acid (Fig. 1B) [13,14]. On the other hand, SSEA1 was expressed on relatively few cells in the H7 and H14 hES cultures and was slightly upregulated after exposure to retinoic acid.

View larger version (12K): [in this window] [in a new window]   Figure 1. The pattern of cell-surface-antigen expression by the hES cell lines, H7 and H14. The percentages of cells expressing SSEA1, SSEA3, SSEA4, TRA-1-60, TRA-1-81, TRA-2-54, and Thy1 were assayed by immunofluorescence and flow cytofluorimetry. A) The average level (+/- standard deviation) of antigen expression in five to seven assays of cells harvested from stock cultures of the H7 hES cell line over a period of 6 months. B) Antigen expression detected in a single assay of the ES cell line H14 cultured on feeder cells in the presence (RA) or absence (NI) of 10-5 M all-trans retinoic acid.

View larger version (69K): [in this window] [in a new window]   Figure 2. RT-PCR analysis of SSEA3+/- and SSEA1+/- subsets of H7 hES cells isolated using fluorescence-activated cell sorting. After screening for genomic contamination (data not shown), 1 µg total RNA was reverse transcribed into first-strand cDNA, which was then subjected to PCR using primers specific to human Oct4, Sox2, FGF4, Rex1, AFP, HBZ, HCG, ND-1, Sox1, and ß-actin (loading control).

After sorting for SSEA1 expression, Oct4 was similarly detected in the SSEA1⁺ and SSEA1^- subsets. However, Rex1, HCG, and Sox1 were more strongly expressed in the SSEA1⁺ subsets. The expression of HCG suggests that the SSEA1⁺ cells include the trophectodermal derivatives, a result consistent with earlier studies of the expression of SSEA1 by choriocarcinoma cell lines [6] and its expression by trophectoderm of mouse [7] and human (see below) blastocysts. The significant expression of Rex1 by the SSEA1⁺ cells is also consistent with trophoblastic differentiation, as previous reports have indicated that Rex1 is expressed by trophectoderm in the mouse [38]. SSEA1 was not significantly discriminatory with respect to the other genes investigated (data not shown).

Together, these results support the notion that hES cells exhibit a cell-surface-antigen phenotype distinct from murine ES cells and that their differentiation into extraembryonic and somatic derivatives is associated with a significant change in surface-antigen expression. To determine whether the surface-antigen phenotype of hES cells does, indeed, correspond to that of the ICM of human blastocysts, early human embryos (n = 52) at cleavage and blastocyst stages, produced after in vitro fertilization treatment of infertile couples, were fixed in 4% paraformaldehyde in PBS and stained by indirect immunofluorescence for the expression of SSEA1, SSEA3, SSEA4, TRA-1-60, and TRA-1-81 (Table 2, Fig. 3). TRA-1-60, TRA-1-81, SSEA3, and SSEA4 were all localized to the ICM in human expanded or hatching blastocysts, although they were absent from mouse embryos at these stages. Conversely, SSEA1 was expressed on the trophectoderm of human blastocysts but not at all on the ICM, though it was expressed on the murine ICM.

View larger version (143K): [in this window] [in a new window]   Figure 3. Typical immunolocalization of human and mouse embryos with stage-specific markers. Phase (left) and epifluorescent micrographs (right). A) SSEA-4/four-cell human embryo—no staining seen. B) SSEA1/expanded human blastocyst—note the surface trophoblast staining. C) TRA-1-60/hatching human blastocyst—note staining of the ICM. D) TRA-1-81/early human blastocyst, staining predominantly of ICM. E) SSEA4/human blastocyst, staining of ICM. F) SSEA4/four-cell mouse embryo—note the surface blastomere staining, contrasting with the absence of staining of four-cell human embryos (A, above). G) TRA-1-60/two-cell mouse embryo—note the staining of the inner surface of zona pellucida and perivitelline space but not of the blastomeres themselves. H) SSEA1/mouse expanded blastocyst, staining of ICM and slight staining of trophoblast.

	DISCUSSION

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Our results indicate that human ICM and cultured ES cells share a common antigen phenotype that resembles that of human EC cells but is distinct from that of murine ICM, EC, and ES cells. Unfortunately, the limited availability of human embryos precluded a direct study of their expression of TRA-2-54 (alkaline phosphatase) and Thy1. However, given all the other features in common, it seems likely that these antigens too are expressed by human ICM cells.

On balance, the RT-PCR analysis of the expression of various developmentally regulated genes in the SSEA3- and SSEA1-sorted subpopulations of hES cell cultures supports the contention that SSEA3 marks the undifferentiated cells and that SSEA1 is expressed by some of their differentiated derivatives, notably putative trophectoderm. However, our analyses were limited by the semiquantitative character of the RT-PCR analyses possible on small populations of sorted cells, and do not permit a conclusion as to whether or not genes, such as Oct4 and Sox2, which appeared to show little difference between SSEA3⁺ and SSEA3^- subsets, might nevertheless show some downregulation upon differentiation in the SSEA3^- cells. Further, in this study, we have not considered the turnover rate of various markers that might permit the persistence of certain transcripts and their corresponding proteins as cells convert from one phenotype to another. Thus, we cannot rule out the presence of "intermediate" transitory cell types that coexpress some features of the undifferentiated stem cells and their differentiated derivatives. This could be particularly the case in the current study in which we have analyzed the subpopulations of cells in asynchronous, spontaneously differentiating cultures of ES cells.

The surface antigens studied in these experiments show marked developmental regulation in both mouse and human embryos. Why, then, the embryos of these two species differ with respect to the expression patterns of these cell surface antigens is unclear. Most of the epitopes studied are associated with oligosaccharides, and one idea is that the core structures of these represent the key functional parts of cell-surface carbohydrates, and that the terminal modifications, which are typically recognized by specific antibodies, are of less functional significance [14,40]. In this respect, it is notable that mouse EC and ICM cells also express the Forssman globoseries glycolipid antigen, as well as globoside itself [41,42], even though they do not express SSEA3 and SSEA4. Since humans lack the glycosyl transferase necessary for the terminal addition of galactosamine to globoside to yield the Forssman structure, the SSEA3 and SSEA4 antigens in humans might perform the same function as Forssman in the mouse. In this model, the key developmental changes would be the switches between synthesis of lactoseries, globoseries, and ganglioseries oligosaccharide core structures, rather than terminal monosaccharide additions recognized by the antibodies used [43].

The TRA-1-60 and TRA-1-81 antigens are keratan sulfate proteoglycans, rather than glycolipids [16,44]. Again, however, it seems likely that the antigenic epitopes are associated with the oligosaccharide components of these molecules. Their function is also unknown, and except for our current results indicating the presence of cross-reacting antigen in the zona pellucida, there is no evidence of expression of these epitopes associated with cell-surface antigens of mouse embryonic cells. However, the core oligosaccharides of keratan sulfate are polylactosamines, fucosylation of which can produce the SSEA1 epitope. Indeed, high-molecular-weight, SSEA1-reactive glycoproteins have been reported to be expressed by murine EC cells [45–47]. It is tempting to consider that the TRA-1-60- and TRA-1-81-reactive proteoglycans of human embryonic cells are members of an equivalent human family of glycoproteins and serve a similar function to the SSEA1-reactive glycoproteins of mouse embryos.

However, the function of these carbohydrate stage-specific embryonic antigens presents a conundrum. There is no doubt that their expression is closely regulated during early development and that changes in expression correlate well with cell differentiation. Further, the SSEA1/Le^x epitope has been reported to play a role in cell:cell adhesion between blastomeres at the morula stage in the mouse [48,49]. On the other hand, many of these carbohydrates are carried as glycolipids; in one study of embryos of the Medaka fish, it was reported that glycolipid expression can be almost extinguished with no evident effect upon embryonic development [50].

Nevertheless, whatever their role in normal development, these antigens could play a role in embryo pathology. The SSEA3 and SSEA4 antigens belong to the P-blood-group system, and those small number of individuals who lack the ability to synthesize the extended globoseries structures that form the basis of these antigens (p^k and pp individuals) lack expression not only of the P-blood-group antigen but also SSEA3 and SSEA4 on their erythrocytes [51]. It has been reported that women with pp and p^k phenotypes display a high rate of spontaneous early abortion, and that abortion in such women is provoked by an immune response to an embryonic antigen [52]. SSEA3 and SSEA4 are clearly obvious targets. Maybe of more significance is the observation that about 1% of Caucasians lack expression of SSEA4 (though not SSEA3 or P antigen), which has been suggested to equate to the Luke blood antigen [51]. This raises the question of whether women with the Luke^-/SSEA4^- phenotype may also be subject to early abortions due to immune responses to early embryonic cells, like pp and p^k women [51].

The contrast in antigen expression between human EC stem cells derived from teratocarcinomas and murine EC and ES cells is well known. That hES cells express a similar antigen phenotype to human EC cells as well as human ICM cells of the early embryo confirms that pluripotent EC and ES cells can provide complementary tools for investigating the molecular mechanisms that underlie cell differentiation in a way that is pertinent to understanding human development. It also suggests that human teratocarcinomas, one of the most common forms of cancer in young men, do indeed arise because of aberrations in the normal mechanisms that guide cell differentiation during embryogenesis [53]. Whatever the reason for the differences in antigen expression patterns seen in the current studies, the results highlight the potential problems in extrapolating results from mouse to human embryos.

	ACKNOWLEDGMENT

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This work was supported in part by a grant from The Wellcome Trust (grant number 016150). Dr. J.K. Henderson was supported by the Infertility Research Trust. We are grateful to Michelle Waknitz, Jessica Antosiewicz, and Christine Pigott for excellent technical assistance. J.K.H. and J.S.D. contributed equally to this work.

	REFERENCES

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1. Thomson JA, Itskovitz-Eldor J, Shapiro SS et al. Embryonic stem cell lines derived from human blastocysts. Science 1998;282:1145–1147.[Abstract/Free Full Text]

2. Reubinoff BE, Pera MF, Fong CY et al. Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro. Nat Biotechnol 2000;18:399–404.[CrossRef][Medline]

3. Andrews PW, Bronson DL, Benham F et al. A comparative study of eight cell lines derived from human testicular teratocarcinoma. Int J Cancer 1980;26:269–280.[Medline]

4. Andrews PW, Goodfellow PN, Shevinsky LH et al. Cell-surface antigens of a clonal human embryonal carcinoma cell line: morphological and antigenic differentiation in culture. Int J Cancer 1982;29:523–531.[Medline]

5. Andrews PW, Damjanov I, Simon D et al. Pluripotent embryonal carcinoma clones derived from the human teratocarcinoma cell line Tera-2: differentiation in vivo and in vitro. Lab Invest 1984;50:147–162.[Medline]

6. Andrews PW, Casper J, Damjanov I et al. Comparative analysis of cell surface antigens expressed by cell lines derived from human germ cell tumours. Int J Cancer 1996;66:806–816.[CrossRef][Medline]

7. Solter D, Knowles BB. Monoclonal antibody defining a stage-specific mouse embryonic antigen (SSEA-1). Proc Natl Acad Sci USA 1978;75:5565–5569.[Abstract/Free Full Text]

8. Gooi HC, Feizi T, Kapadia A et al. Stage-specific embryonic antigen involves 13 fucosylated type 2 blood group chains. Nature 1981;292:156–158.[CrossRef][Medline]

9. Shevinsky LH, Knowles BB, Damjanov I et al. Monoclonal antibody to murine embryos defines a stage-specific embryonic antigen expressed on mouse embryos and human teratocarcinoma cells. Cell 1982;30:697–705.[CrossRef][Medline]

10. Kannagi R, Cochran NA, Ishigami F et al. Stage-specific embryonic antigens (SSEA-3 and -4) are epitopes of a unique globo-series ganglioside isolated from human teratocarcinoma cells. EMBO J 1983;2:2355–2361.[Medline]

11. Solter D, Shevinsky LH, Knowles BB et al. The induction of antigenic changes in a teratocarcinoma stem cell line (F9) by retinoic acid. Dev Biol 1979;70:515–521.[CrossRef][Medline]

12. Martin GR, Lock LF. Pluripotent cell lines derived from mouse embryos cultured in medium conditioned by teratocarcinoma stem cells, section 9. In: Silver LM, Martin GR, Strickland S, eds. Teratocarcinoma Stem Cells. Cold Spring Harbor, NY: Cold Spring Harbor Press, 1983:635-646.

13. Andrews PW. Retinoic acid induces neuronal differentiation of a cloned human embryonal carcinoma cell line in vitro. Dev Biol 1984;103:285–293.[CrossRef][Medline]

14. Fenderson BA, Andrews PW, Nudelman E et al. Glycolipid core structure switching from globo- to lacto- and ganglio-series during retinoic acid-induced differentiation of TERA-2-derived human embryonal carcinoma cells. Dev Biol 1987;122:21–34.[CrossRef][Medline]

15. Andrews PW, Banting GS, Damjanov I et al. Three monoclonal antibodies defining distinct differentiation antigens associated with different high molecular weight polypeptides on the surface of human embryonal carcinoma cells. Hybridoma 1984;3:347–361.[Medline]

16. Badcock G, Pigott C, Goepel J et al. The human embryonal carcinoma marker antigen TRA-1-60 is a sialylated keratan sulphate proteoglycan. Cancer Res 1999;59:4715–4719.[Abstract/Free Full Text]

17. Andrews PW, Oosterhuis JW, Damjanov I. Cell lines from human germ cell lines. In: Robertson EJ, ed. Teratocarcinomas and Embryonic Stem Cells: A Practical Approach. Oxford: IRL Press, 1987:207-248.

18. Andrews PW, Meyer LJ, Bednarz KL et al. Two monoclonal antibodies recognizing determinants on human embryonal carcinoma cells react specifically with the liver isozyme of human alkaline phosphatase. Hybridoma 1984;3:33–39.[Medline]

19. Williams BP, Daniels GL, Pym B et al. Biochemical and genetic analysis of the OKa blood group antigen. Immunogenetics 1988;27:322–329.[CrossRef][Medline]

20. McKenzie JL, Fabre JW. Human thy-1: unusual localization and possible functional significance in lymphoid tissues. J Immunol 1981;126:843–850.[Abstract]

21. Duran C, Talley PJ, Walsh J et al. Hybrids of pluripotent and nullipotent human embryonal carcinoma cells: partial retention of a pluripotent phenotype. Int J Cancer 2001;93:324–332.[CrossRef][Medline]

22. Schuldiner M, Yanuka O, Itskovitz-Eldor J et al. Effects of eight growth factors on the differentiation of cells derived from human embryonic stem cells. Proc Natl Acad Sci USA 2000;97:11307–11312.[Abstract/Free Full Text]

23. Altschul SF, Gish W, Miller W et al. Basic local alignment search tool. J Mol Biol 1990;215:403–410.[CrossRef][Medline]

24. Ben-Shushan E, Thompson JR, Gudas LJ et al. Rex-1, a gene encoding a transcription factor expressed in the early embryo, is regulated via Oct-3/4 and Oct-6 binding to an octamer site and a novel protein, Rox-1, binding to an adjacent site. Mol Cell Biol 1998;18:1866–1878.[Abstract/Free Full Text]

25. Berstine EG, Hooper ML, Grandchamp S et al. Alkaline phosphatase activity in mouse teratoma. Proc Natl Acad Sci USA 1973;70:3899–3903.[Abstract/Free Full Text]

26. Stern PL, Martin GR, Evans MJ. Cell surface antigens of clonal teratocarcinoma cells at various stages of differentiation. Cell 1975;6:455–465.[CrossRef]

27. Andrews PW, Goodfellow PN, Bronson DL. Cell surface characteristics and other markers of differentiation of human teratocarcinomas in culture. In: Silver LM, Martin GR, Strickland S, eds. Teratocarcinoma Stem Cells. Cold Spring Harbor Conferences on Cell Proliferation . 1983;10:579–590.

28. Collignon J, Sockanathan S, Hacker A et al. A comparison of the properties of Sox-3 with Sry and two related genes, Sox-1 and Sox-2. Development 1996;122:509–520.[Abstract]

29. Rosner MH, Vigano MA, Ozato K et al. A POU-domain transcription factor in early stem cells and germ cells of the mammalian embryo. Nature 1990;345:686–692.[CrossRef][Medline]

30. Fraidenraich D, Lang R, Basilico C. Distinct regulatory elements govern Fgf4 gene expression in the mouse blastocyst, myotomes, and developing limb. Dev Biol 1998;204:197–209.[CrossRef][Medline]

31. Heikinheimo O, Dong KW, Lanzendorf SE et al. Primate reproductive organs reveal a novel pattern of proto-oncogene c-mos and transcription factor Oct-3 mRNA expression. Mol Reprod Dev 1995;42:397–406.[CrossRef][Medline]

32. Assady S, Maor G, Amit M et al. Insulin production by human embryonic stem cells. Diabetes 2001;50:1691–1697.[Abstract/Free Full Text]

33. Peschle C, Mavilio F, Care A et al. Haemoglobin switching in human embryos: asynchrony of zeta—alpha and epsilon—gamma-globin switches in primitive and definite erythropoietic lineage. Nature 1985;313:235–238.[CrossRef][Medline]

34. Gitlin D, Boesman MJ. Sites of serum alpha-fetoprotein synthesis in the human and in the rat. J Clin Invest 1967;46:1010–1016.

35. Midgley AR, Pierce GB. Immunohistochemical localization of human chorionic gonadotropin. J Exp Med 1962;115:284–294.

36. Pevny LH, Sockanathan S, Placzek M et al. A role for SOX1 in neural determination. Development 1998;125:1967–1978.[Abstract]

37. Lee JE, Hollenberg SM, Snider L et al. Conversion of Xenopus ectoderm into neurons by NeuroD, a basic helix-loop-helix protein. Science 1995;268:836–844.[Abstract/Free Full Text]

38. Rogers MB, Hosler BA, Gudas LJ. Specific expression of a retinoic acid-regulated, zinc-finger gene, Rex-1, in preimplantation embryos, trophoblast and spermatocytes. Development 1991;113:815–824.[Abstract]

39. McGrath J, Solter D. Nuclear transplantation in mouse embryos. J Exp Zool 1983;228:355–362.[CrossRef][Medline]

40. Fenderson BA, Andrews PW. Carbohydrate antigens of embryonal carcinoma cells: changes upon differentiation. APMIS 1992;100(suppl 27):109–118.

41. Willison KR, Karol RA, Suzuki A et al. Neutral glycolipid antigens as developmental markers of mouse teratocarcinoma and early embryos: an immunologic and chemical analysis. J Immunol 1982;129:603–609.[Abstract]

42. Krupnick JG, Damjanov I, Damjanov A et al. Globo-series carbohydrate antigens are expressed in different forms on human and murine teratocarcinoma-derived cells. Int J Cancer 1994;59:692–698.[Medline]

43. Chen C, Fenderson BA, Andrews PW et al. Glycolipid glycosyltransferases in human embryonal carcinoma cells during retinoic acid-induced differentiation. Biochemistry 1989;28:2229–2238.[CrossRef][Medline]

44. Fenderson BA, Radin N, Andrews PW. Differentiation antigens of human germ cell tumours: distribution of carbohydrate epitopes on glycolipids and glycoproteins analysed using PDMP, an inhibitor of glycolipid synthesis. Eur Urol 1993;2:30–37.

45. Childs RA, Pennington J, Uemura K et al. High-molecular-weight glycoproteins are the major carriers of the carbohydrate differentiation antigens I, i and SSEA-1 of mouse teratocarcinoma cells. Biochem J 1983;215:491–503.[Medline]

46. Ozawa M, Muramatsu T, Solter D. SSEA-1, a stage-specific embryonic antigen of the mouse, is carried by the glycoprotein-bound large carbohydrate in embryonal carcinoma cells. Cell Diff 1985;16:169–173.[Medline]

47. Rosenman SJ, Fenderson BA, Hakormori S-I. Murine embryonal carcinoma cell-surface sialyl LeX is present on a novel glycoprotein and on high-molecular-weight lactosaminoglycan. Exp Cell Res 1989;180:326–340.[CrossRef][Medline]

48. Fenderson BA, Zehavi U, Hakomori S. A multivalent lacto-n-fucopentaose III-lysyllysine conjugate decompacts preimplantation mouse embryos, while the free oligosaccharide is ineffective. J Exp Med 1984;160:1591–1596.[Abstract/Free Full Text]

49. Bird JM, Kimber SJ. Oligosaccharides containing fucose linked (13) and (14) to N-acetylglucosamine cause decompaction of mouse morulae. Dev Biol 1984;104:449–460.[CrossRef][Medline]

50. Fenderson BA, Ostrander GK, Hausken Z et al. A ceramide analogue (PDMP) inhibits glycolipid synthesis in fish embryos. Exp Cell Res 1992;198:362–366.[CrossRef][Medline]

51. Tippett P, Andrews PW, Knowles BB et al. Red cell antigens P (globoside) and Luke: identification by monoclonal antibodies defining the murine stage-specific embryonic antigens -3 and -4 (SSEA-3 and SSEA-4). Vox Sang 1986;51:53–56.[Medline]

52. Race RR, Sanger R. The P Blood Groups. In: Blood Groups in Man, Sixth Edition. Oxford, UK: Blackwell Scientific, 1975:139-168.

53. Andrews PW. Teratocarcinomas and human embryology: pluripotent human EC cell lines. APMIS 1998;106:158–168.[Medline]

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				A. K. Vaags, S. Rosic-Kablar, C. J. Gartley, Y. Z. Zheng, A. Chesney, D. A.F. Villagomez, S. A. Kruth, and M. R. Hough Derivation and Characterization of Canine Embryonic Stem Cell Lines with In Vitro and In Vivo Differentiation Potential Stem Cells, February 1, 2009; 27(2): 329 - 340. [Abstract] [Full Text] [PDF]

				C. L. Bauwens, R. Peerani, S. Niebruegge, K. A. Woodhouse, E. Kumacheva, M. Husain, and P. W. Zandstra Control of Human Embryonic Stem Cell Colony and Aggregate Size Heterogeneity Influences Differentiation Trajectories Stem Cells, September 1, 2008; 26(9): 2300 - 2310. [Abstract] [Full Text] [PDF]

				C. M. Cameron, F. Harding, W.-S. Hu, and D. S. Kaufman Activation of Hypoxic Response in Human Embryonic Stem Cell-Derived Embryoid Bodies Experimental Biology and Medicine, August 1, 2008; 233(8): 1044 - 1057. [Abstract] [Full Text] [PDF]

				H. Fong, K. A. Hohenstein, and P. J. Donovan Regulation of Self-Renewal and Pluripotency by Sox2 in Human Embryonic Stem Cells Stem Cells, August 1, 2008; 26(8): 1931 - 1938. [Abstract] [Full Text] [PDF]

				M. D. O'Connor, M. D. Kardel, I. Iosfina, D. Youssef, M. Lu, M. M. Li, S. Vercauteren, A. Nagy, and C. J. Eaves Alkaline Phosphatase-Positive Colony Formation Is a Sensitive, Specific, and Quantitative Indicator of Undifferentiated Human Embryonic Stem Cells Stem Cells, May 1, 2008; 26(5): 1109 - 1116. [Abstract] [Full Text] [PDF]

				A. S. Boyd, D. C. Wu, Y. Higashi, and K. J. Wood A Comparison of Protocols Used to Generate Insulin-Producing Cell Clusters from Mouse Embryonic Stem Cells Stem Cells, May 1, 2008; 26(5): 1128 - 1137. [Abstract] [Full Text] [PDF]

				C. L. Kerr, C. M. Hill, P. D. Blumenthal, and J. D. Gearhart Expression of pluripotent stem cell markers in the human fetal ovary Hum. Reprod., March 1, 2008; 23(3): 589 - 599. [Abstract] [Full Text] [PDF]

				J. Pruszak, K.-C. Sonntag, M. H. Aung, R. Sanchez-Pernaute, and O. Isacson Markers and Methods for Cell Sorting of Human Embryonic Stem Cell-Derived Neural Cell Populations Stem Cells, September 1, 2007; 25(9): 2257 - 2268. [Abstract] [Full Text] [PDF]

				S. Ahmad, R. Stewart, S. Yung, S. Kolli, L. Armstrong, M. Stojkovic, F. Figueiredo, and M. Lako Differentiation of Human Embryonic Stem Cells into Corneal Epithelial-Like Cells by In Vitro Replication of the Corneal Epithelial Stem Cell Niche Stem Cells, May 1, 2007; 25(5): 1145 - 1155. [Abstract] [Full Text] [PDF]

				E. J. Gang, D. Bosnakovski, C. A. Figueiredo, J. W. Visser, and R. C. R. Perlingeiro SSEA-4 identifies mesenchymal stem cells from bone marrow Blood, February 15, 2007; 109(4): 1743 - 1751. [Abstract] [Full Text] [PDF]

				D. Rajesh, N. Chinnasamy, S. M. Mitalipov, D. P. Wolf, I. Slukvin, J. A. Thomson, and A. F. Shaaban Differential Requirements for Hematopoietic Commitment Between Human and Rhesus Embryonic Stem Cells Stem Cells, February 1, 2007; 25(2): 490 - 499. [Abstract] [Full Text] [PDF]

				M. Bhatia Hematopoietic Development from Human Embryonic Stem Cells Hematology, January 1, 2007; 2007(1): 11 - 16. [Abstract] [Full Text] [PDF]

				S. N. Brimble, E. S. Sherrer, E. W. Uhl, E. Wang, S. Kelly, A. H. Merrill Jr., A. J. Robins, and T. C. Schulz The Cell Surface Glycosphingolipids SSEA-3 and SSEA-4 Are Not Essential for Human ESC Pluripotency Stem Cells, January 1, 2007; 25(1): 54 - 62. [Abstract] [Full Text] [PDF]

				J. E. Huettner, A. Lu, Y. Qu, Y. Wu, M. Kim, and J. W. McDonald Gap Junctions and Connexon Hemichannels in Human Embryonic Stem Cells Stem Cells, July 1, 2006; 24(7): 1654 - 1667. [Abstract] [Full Text] [PDF]

				R. Harun, L. Ruban, M. Matin, J. Draper, N.M. Jenkins, G.C. Liew, P.W. Andrews, T.C. Li, S.M. Laird, and H.D.M. Moore Cytotrophoblast stem cell lines derived from human embryonic stem cells and their capacity to mimic invasive implantation events Hum. Reprod., June 1, 2006; 21(6): 1349 - 1358. [Abstract] [Full Text] [PDF]

				H. Shibata, N. Ageyama, Y. Tanaka, Y. Kishi, K. Sasaki, S. Nakamura, S.-i. Muramatsu, S. Hayashi, Y. Kitano, K. Terao, et al. Improved Safety of Hematopoietic Transplantation with Monkey Embryonic Stem Cells in the Allogeneic Setting Stem Cells, June 1, 2006; 24(6): 1450 - 1457. [Abstract] [Full Text] [PDF]

				E. Rajpert-De Meyts Developmental model for the pathogenesis of testicular carcinoma in situ: genetic and environmental aspects Hum. Reprod. Update, May 1, 2006; 12(3): 303 - 323. [Abstract] [Full Text] [PDF]

				J. D. Raman, N. P. Mongan, L. Liu, S. K. Tickoo, D. M. Nanus, D. S. Scherr, and L. J. Gudas Decreased expression of the human stem cell marker, Rex-1 (zfp-42), in renal cell carcinoma Carcinogenesis, March 1, 2006; 27(3): 499 - 507. [Abstract] [Full Text] [PDF]

				T. W. Plaia, R. Josephson, Y. Liu, X. Zeng, C. Ording, A. Toumadje, S. N. Brimble, E. S. Sherrer, E. W. Uhl, W. J. Freed, et al. Characterization of a New NIH-Registered Variant Human Embryonic Stem Cell Line, BG01V: A Tool for Human Embryonic Stem Cell Research Stem Cells, March 1, 2006; 24(3): 531 - 546. [Abstract] [Full Text] [PDF]

				S. P. Raikwar, T. Mueller, and N. Zavazava Strategies for Developing Therapeutic Application of Human Embryonic Stem Cells Physiology, February 1, 2006; 21(1): 19 - 28. [Abstract] [Full Text] [PDF]

				T. Enver, S. Soneji, C. Joshi, J. Brown, F. Iborra, T. Orntoft, T. Thykjaer, E. Maltby, K. Smith, R. A. Dawud, et al. Cellular differentiation hierarchies in normal and culture-adapted human embryonic stem cells Hum. Mol. Genet., November 1, 2005; 14(21): 3129 - 3140. [Abstract] [Full Text] [PDF]

				L. Vallier, M. Alexander, and R. A. Pedersen Activin/Nodal and FGF pathways cooperate to maintain pluripotency of human embryonic stem cells J. Cell Sci., October 1, 2005; 118(19): 4495 - 4509. [Abstract] [Full Text] [PDF]

				T. Miki, T. Lehmann, H. Cai, D. B. Stolz, and S. C. Strom Stem Cell Characteristics of Amniotic Epithelial Cells Stem Cells, October 1, 2005; 23(10): 1549 - 1559. [Abstract] [Full Text] [PDF]

				A. Yanagisawa, C. Endo, K. Okawa, S. Shitara, H. Kugoh, M. Kakitani, M. Oshimura, and K. Tomizuka Generation of Chromosome-Specific Monoclonal Antibodies Using In Vitro-Differentiated Transchromosomic Mouse Embryonic Stem Cells Stem Cells, October 1, 2005; 23(10): 1479 - 1488. [Abstract] [Full Text] [PDF]

				Y. S. Son, J. H. Park, Y. K. Kang, J.-S. Park, H. S. Choi, J. Y. Lim, J. E. Lee, J. B. Lee, M. S. Ko, Y.-S. Kim, et al. Heat Shock 70-kDa Protein 8 Isoform 1 Is Expressed on the Surface of Human Embryonic Stem Cells and Downregulated upon Differentiation Stem Cells, October 1, 2005; 23(10): 1502 - 1513. [Abstract] [Full Text] [PDF]

				R. I. Skotheim, G. E. Lind, O. Monni, J. M. Nesland, V. M. Abeler, S. D. Fossa, N. Duale, G. Brunborg, O. Kallioniemi, P. W. Andrews, et al. Differentiation of Human Embryonal Carcinomas In vitro and In vivo Reveals Expression Profiles Relevant to Normal Development Cancer Res., July 1, 2005; 65(13): 5588 - 5598. [Abstract] [Full Text] [PDF]

				L. Wang, E. Duan, L.-y. Sung, B.-S. Jeong, X. Yang, and X. C. Tian Generation and Characterization of Pluripotent Stem Cells from Cloned Bovine Embryos Biol Reprod, July 1, 2005; 73(1): 149 - 155. [Abstract] [Full Text] [PDF]

				P. J. Tesar Derivation of germ-line-competent embryonic stem cell lines from preblastocyst mouse embryos PNAS, June 7, 2005; 102(23): 8239 - 8244. [Abstract] [Full Text] [PDF]

				A. M. Wobus and K. R. Boheler Embryonic Stem Cells: Prospects for Developmental Biology and Cell Therapy Physiol Rev, April 1, 2005; 85(2): 635 - 678. [Abstract] [Full Text] [PDF]

				G. M. Beattie, A. D. Lopez, N. Bucay, A. Hinton, M. T. Firpo, C. C. King, and A. Hayek Activin A Maintains Pluripotency of Human Embryonic Stem Cells in the Absence of Feeder Layers Stem Cells, April 1, 2005; 23(4): 489 - 495. [Abstract] [Full Text] [PDF]

				J. Inzunza, K. Gertow, M. A. Stromberg, E. Matilainen, E. Blennow, H. Skottman, S. Wolbank, L. Ahrlund-Richter, and O. Hovatta Derivation of Human Embryonic Stem Cell Lines in Serum Replacement Medium Using Postnatal Human Fibroblasts as Feeder Cells Stem Cells, April 1, 2005; 23(4): 544 - 549. [Abstract] [Full Text] [PDF]

				T. Ezashi, P. Das, and R. M. Roberts Low O2 tensions and the prevention of differentiation of hES cells PNAS, March 29, 2005; 102(13): 4783 - 4788. [Abstract] [Full Text] [PDF]

				P. Stojkovic, M. Lako, R. Stewart, S. Przyborski, L. Armstrong, J. Evans, A. Murdoch, T. Strachan, and M. Stojkovic An Autogeneic Feeder Cell System That Efficiently Supports Growth of Undifferentiated Human Embryonic Stem Cells Stem Cells, March 1, 2005; 23(3): 306 - 314. [Abstract] [Full Text] [PDF]

				G. Cauffman, H. Van de Velde, I. Liebaers, and A. Van Steirteghem Oct-4 mRNA and protein expression during human preimplantation development Mol. Hum. Reprod., March 1, 2005; 11(3): 173 - 181. [Abstract] [Full Text] [PDF]

				J. B. Lee, J. E. Lee, J. H. Park, S. J. Kim, M. K. Kim, S. I. Roh, and H. S. Yoon Establishment and Maintenance of Human Embryonic Stem Cell Lines on Human Feeder Cells Derived from Uterine Endometrium under Serum-Free Condition Biol Reprod, January 1, 2005; 72(1): 42 - 49. [Abstract] [Full Text] [PDF]

				H. Fulka, M. Mrazek, O. Tepla, and J. Fulka Jr DNA methylation pattern in human zygotes and developing embryos Reproduction, December 1, 2004; 128(6): 703 - 708. [Abstract] [Full Text] [PDF]

				T. Dvash, Y. Mayshar, H. Darr, M. McElhaney, D. Barker, O. Yanuka, K. J. Kotkow, L. L. Rubin, N. Benvenisty, and R. Eiges Temporal gene expression during differentiation of human embryonic stem cells and embryoid bodies Hum. Reprod., December 1, 2004; 19(12): 2875 - 2883. [Abstract] [Full Text] [PDF]

				D. P. Wolf, H.-C. Kuo, K.-Y. F. Pau, and L. Lester Progress with Nonhuman Primate Embryonic Stem Cells Biol Reprod, December 1, 2004; 71(6): 1766 - 1771. [Abstract] [Full Text] [PDF]

				M. F. Pera and A. O. Trounson Human embryonic stem cells: prospects for development Development, November 15, 2004; 131(22): 5515 - 5525. [Abstract] [Full Text] [PDF]

				D. Besser Expression of Nodal, Lefty-A, and Lefty-B in Undifferentiated Human Embryonic Stem Cells Requires Activation of Smad2/3 J. Biol. Chem., October 22, 2004; 279(43): 45076 - 45084. [Abstract] [Full Text] [PDF]

				M. Stojkovic, M. Lako, T. Strachan, and A. Murdoch Derivation, growth and applications of human embryonic stem cells Reproduction, September 1, 2004; 128(3): 259 - 267. [Abstract] [Full Text] [PDF]

				M. M. Matin, J. R. Walsh, P. J. Gokhale, J. S. Draper, A. R. Bahrami, I. Morton, H. D. Moore, and P. W. Andrews Specific Knockdown of Oct4 and {beta}2-microglobulin Expression by RNA Interference in Human Embryonic Stem Cells and Embryonic Carcinoma Cells Stem Cells, September 1, 2004; 22(5): 659 - 668. [Abstract] [Full Text] [PDF]

				H. Kubota, M. R. Avarbock, and R. L. Brinster Culture Conditions and Single Growth Factors Affect Fate Determination of Mouse Spermatogonial Stem Cells Biol Reprod, September 1, 2004; 71(3): 722 - 731. [Abstract] [Full Text] [PDF]

				S. K. Dhara and N. Benvenisty Gene trap as a tool for genome annotation and analysis of X chromosome inactivation in human embryonic stem cells Nucleic Acids Res., July 29, 2004; 32(13): 3995 - 4002. [Abstract] [Full Text] [PDF]

				J. Inzunza, S. Sahlen, K. Holmberg, A.-M. Stromberg, H. Teerijoki, E. Blennow, O. Hovatta, and H. Malmgren Comparative genomic hybridization and karyotyping of human embryonic stem cells reveals the occurrence of an isodicentric X chromosome after long-term cultivation Mol. Hum. Reprod., June 1, 2004; 10(6): 461 - 466. [Abstract] [Full Text] [PDF]

				M.-S. Tsai, J.-L. Lee, Y.-J. Chang, and S.-M. Hwang Isolation of human multipotent mesenchymal stem cells from second-trimester amniotic fluid using a novel two-stage culture protocol Hum. Reprod., June 1, 2004; 19(6): 1450 - 1456. [Abstract] [Full Text] [PDF]

				A. T. Clark, M. S. Bodnar, M. Fox, R. T. Rodriquez, M. J. Abeyta, M. T. Firpo, and R. A. R. Pera Spontaneous differentiation of germ cells from human embryonic stem cells in vitro Hum. Mol. Genet., April 1, 2004; 13(7): 727 - 739. [Abstract] [Full Text] [PDF]

				M. J. Abeyta, A. T. Clark, R. T. Rodriguez, M. S. Bodnar, R. A. R. Pera, and M. T. Firpo Unique gene expression signatures of independently-derived human embryonic stem cell lines Hum. Mol. Genet., March 15, 2004; 13(6): 601 - 608. [Abstract] [Full Text] [PDF]

				M. Richards, S.-P. Tan, J.-H. Tan, W.-K. Chan, and A. Bongso The Transcriptome Profile of Human Embryonic Stem Cells as Defined by SAGE Stem Cells, January 1, 2004; 22(1): 51 - 64. [Abstract] [Full Text] [PDF]

				J. M. Sperger, X. Chen, J. S. Draper, J. E. Antosiewicz, C. H. Chon, S. B. Jones, J. D. Brooks, P. W. Andrews, P. O. Brown, and J. A. Thomson Gene expression patterns in human embryonic stem cells and human pluripotent germ cell tumors PNAS, November 11, 2003; 100(23): 13350 - 13355. [Abstract] [Full Text] [PDF]

				C. Selden, S.-A. Chalmers, C. Jones, R. Standish, A. Quaglia, N. Rolando, A. K. Burroughs, K. Rolles, A. Dhillon, and H. J.F. Hodgson Epithelial Colonies Cultured from Human Explanted Liver in Subacute Hepatic Failure Exhibit Hepatocyte, Biliary Epithelial, and Stem Cell Phenotypic Markers Stem Cells, November 1, 2003; 21(6): 624 - 631. [Abstract] [Full Text] [PDF]

				M. Richards, S. Tan, C.-Y. Fong, A. Biswas, W.-K. Chan, and A. Bongso Comparative Evaluation of Various Human Feeders for Prolonged Undifferentiated Growth of Human Embryonic Stem Cells Stem Cells, September 1, 2003; 21(5): 546 - 556. [Abstract] [Full Text] [PDF]

				C. R. Cogle, S. M. Guthrie, R. C. Sanders, W. L. Allen, E. W. Scott, and B. E. Petersen An Overview of Stem Cell Research and Regulatory Issues Mayo Clin. Proc., August 1, 2003; 78(8): 993 - 1003. [Abstract] [PDF]

				L. Cheng, H. Hammond, Z. Ye, X. Zhan, and G. Dravid Human Adult Marrow Cells Support Prolonged Expansion of Human Embryonic Stem Cells in Culture Stem Cells, March 1, 2003; 21(2): 131 - 142. [Abstract] [Full Text] [PDF]

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