You searched for: ImmunoCult-XF T cell culture medium

Bispecific antibodies directed against tumor-associated target antigens and to surface receptors mediating T-cell activation, such as the TCR/CD3 complex and the costimulatory receptor CD28, are capable of mediating T-cell activation resulting in tumor cell killing. In this study, we used the B-cell-associated antigens CD19 and CD20 as target structures on human leukemic cells. We found that a combination of bispecific antibody fragments (bsFab2) with target x CD3 and target x CD28 specificity induces vigorous autologous T-cell activation and killing of malignant cells in peripheral blood and bone marrow cultures from patients with chronic lymphocytic leukemia and follicular lymphoma. The bsFab2 targeting CD20 were considerably more effective than those binding to CD19. The colony-forming capacity of treated bone marrow was impaired due to large amounts of tumor necrosis factor alpha produced during bsFab2-induced T-cell activation. Neutralizing tumor necrosis factor alpha antibodies were found to reverse this negative effect without affecting T-cell activation and tumor cell killing. CD20 x CD28 bsFab2, when used alone rather than in combination, markedly improved the recognition of leukemic cells by allogeneic T cells. Therefore, these reagents may be capable of enhancing the immunogenicity of leukemic cells in general and, in particular, of increasing the antileukemic activity of allogeneic donor buffy coat cells in relapsed bone marrow transplanted patients. View Publication

Conventionally, mesenchymal stem cells (MSC) are generated by plating cells from bone marrow (BM) or other sources into culture flasks and selecting plastic-adherent cells with fibroblastoid morphology. These cells express CD9, CD10, CD13, CD73, CD105, CD166, and other markers but show only a weak or no expression of the embryonic markers stage-specific embryonic antigen-4 (SSEA-4), Oct-4 and nanog-3. Using a novel protocol we prepared MSC from BM and non-amniotic placenta (PL) by culture of Ficoll-selected cells in gelatin-coated flasks in the presence of a serum-free, basic fibroblast growth factor (b-FGF)-containing medium that was originally designed for the expansion of human embryonic stem cells (ESC). MSC generated in gelatin-coated flasks in the presence of ESC medium revealed a four-to fivefold higher proliferation rate than conventionally prepared MSC which were grown in uncoated flasks in serum-containing medium. In contrast, the colony forming unit fibroblast number was only 1.5- to twofold increased in PL-MSC and not affected in BM-MSC. PL-MSC grown in ESC medium showed an increased surface expression of SSEA-4 and frizzled-9 (FZD-9), an increased Oct-4 and nestin mRNA expression, and an induced expression of nanog-3. BM-MSC showed an induced expression of FZD-9, nanog-3, and Oct-4. In contrast to PL-MSC, only BM-MSC expressed the MSC-specific W8B2 antigen. When cultured under appropriate conditions, these MSC gave rise to functional adipocytes and osteoblast-like cells (mesoderm), glucagon and insulin expressing pancreatic-like cells (endoderm), as well as cells expressing the neuronal markers neuron-specific enolase, glutamic acid decarboxylase-67 (GAD), or class III beta-tubulin, and the astrocyte marker glial fibrillary acidic protein (ectoderm). In conclusion, using a novel protocol we demonstrate that adult BM-and neonatal PL-derived MSC can be induced to express high levels of FZD-9, Oct-4, nanog-3, and nestin and are able of multi-lineage differentiation. View Publication

The aim of this study was to standardize in vitro culture conditions for human acute lymphoblastic leukemia (ALL) cells. The cells were cultured in medium containing 10% fetal calf serum (FCS) and in the four serum-free media X-vivo 10, X-vivo 15, X-vivo 20 and Stem Span. Native ALL blasts could proliferate in all four serum-free media, but the strongest responses were usually observed with Stem Span. Native leukemia blasts were also cultured in the presence of various single cytokines or cytokine combinations. The highest proliferation was usually observed in the presence of Flt3-Ligand (Flt3-L) when single cytokines were examined, and these responses could be further increased especially by combining Flt3-L with interleukin 3 (IL3), IL7 or stem cell factor (SCF). Proliferation could also be increased when ALL blasts were cultured in the presence of two commercially available fibroblast cell lines (Hs27 and HFL1). Based on these results we suggest that in vitro culture conditions for native human ALL blasts can be standardized by using serum-free culture media supplemented with exogenous Flt3-L+IL3+SCF, and the use of accessory cells can also be standardized by using well-characterized fibroblast cell lines. Detectable ALL blast proliferation can then be observed for most patients. Our experimental model can thereby be used for in vitro evaluation of possible antileukemic treatment strategies, and it will then allow comparison of experimental results between different studies. View Publication

BACKGROUND: Ex vivo expansion of cord blood (CB) hematopoietic stem and progenitor cells increases cell dose and may reduce the severity and duration of neutropenia and thrombocytopenia after transplantation. This study's purpose was to establish a clinically applicable culture system by investigating the use of cytokines, serum-free media, and autologous plasma for the expansion of CB cells and the engraftment of expanded product in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. STUDY DESIGN AND METHODS: Enriched CB CD34+ cells were cultured in four media (Iscove's modified Dulbecco's medium with FCS, Gibco; X-Vivo-10, BioWhittaker; QBSF-60, Quality Biological; and StemSpan SFEM, Stem Cell Technologies) with four cytokine combinations (thrombopoietin [TPO], SCF, Flt-3 ligand [FL] with and without G-CSF, and/or IL-6). The effect of autologous CB plasma was also investigated. The read-out measures were evaluated on Days 8 and 12. After expansion at the optimized condition, cultured cells were transplanted into sublethally irradiated NOD/SCID mice. The engraftment of human CD45+ cells and subsets in the bone marrow, spleen, and peripheral blood was determined. RESULTS: QBSF-60 or StemSpan SFEM supported high yields of early progenitors (CD34+ cells, textlessor= 64.8-fold; CD34+CD38- cells, 330-fold; CFU-granulocyte erythroid macrophage megakaryocyte [GEMM], 248-fold) and CFUs of the myeloid (CFU-GM, 407-fold) and erythroid (BFU/CFU-E, 144-fold) lineages. The expansion of the megakaryocytic lineage was consistently higher in X-Vivo-10 (CFU-megakaryocyte, 684-fold). Autologous plasma promoted colony formation but reduced CD34+ cells and CFU-GEMM. The addition of G-CSF or IL-6 improved cell yields; G-CSF was more effective for committed progenitors. Expansion products from cultures in QBSF-60 with the cytokines engrafted and differentiated into the myeloid and lymphoid lineages in NOD/SCID mice. CONCLUSION: The data supported the strategy of expansion. The optimized condition may be applicable to clinical expansion for the abrogation or reduction of posttransplant cytopenia. View Publication

BACKGROUND Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are in the foreground as a preferable application for treating diseases. However, the safety of hUC-MSCs after long-term culturing in vitro in serum-free medium remains unclear. METHODS hUC-MSCs were separated by adherent tissue culture. hUC-MSCs were cultured in serum-free MesenCult-XF medium and FBS-bases DMEM complete medium. At the 1st, 3rd, 5th, 8th, 10th, and 15th passage, the differentiation of MSCs into osteogenic, chondrogenic, and adipogenic cells was detected, and MTT, surface antigens were measured. Tumorigenicity was analyzed at the 15th passage. Conventional karyotyping was performed at passage 0, 8, and 15. The telomerase activity of hUC-MSCs at passage 1-15 was analyzed. RESULTS Flow cytometry analysis showed that very high expression was detected for CD105, CD73, and CD90 and very low expression for CD45, CD34, CD14, CD79a, and HLA-DR. MSCs could differentiate into osteocytes, chondrocytes, and adipocytes in vitro. There was no obvious chromosome elimination, displacement, or chromosomal imbalance as determined from the guidelines of the International System for Human Cytogenetic Nomenclature. Telomerase activity was down-regulated significantly when the culture time was prolonged. Further, no tumors formed in rats injected with hUC-MSCs (P15) cultured in serum-free and in serum-containing conditions. CONCLUSION Our data showed that hUC-MSCs met the International Society for Cellular Therapy standards for conditions of long-term in vitro culturing at P15. Since hUC-MSCs can be safely expanded in vitro and are not susceptible to malignant transformation in serum-free medium, these cells are suitable for cell therapy. View Publication

Mesenchymal stem cells (MSCs) are multipotent adult stem cells that have an immunosuppressive effect. The biological stability of MSCs in serum-free medium during long-term culture in vitro has not been elucidated clearly. The morphology, immunophenotype and multi-lineage potential were analyzed at passages 3, 5, 10, 15, 20, and 25 (P3, P5, P10, P15, P20, and P25, respectively). The cell cycle distribution, apoptosis, and karyotype of human umbilical cord-derived (hUC)-MSCs were analyzed at P3, P5, P10, P15, P20, and P25. From P3 to P25, the three defining biological properties of hUC-MSCs [adherence to plastic, specific surface antigen expression, multipotent differentiation potential] met the standards proposed by the International Society for Cellular Therapy for definition of MSCs. The cell cycle distribution analysis at the P25 showed that the percentage of cells at G0/G1 was increased, compared with the cells at P3 (P textless 0.05). Cells at P25 displayed an increase in the apoptosis rate (to 183 %), compared to those at P3 (P textless 0.01). Within subculture generations 3-20 (P3-P20), the differences between the cell apoptotic rates were not statistically significant (P textgreater 0.05). There were no detectable chromosome eliminations, displacements, or chromosomal imbalances, as assessed by the karyotyping guidelines of the International System for Human Cytogenetic Nomenclature (ISCN, 2009). Long-term culture affects the biological stability of MSCs in serum-free MesenCult-XF medium. MSCs can be expanded up to the 25th passage without chromosomal changes by G-band. The best biological activity period and stability appeared between the third to 20th generations. View Publication

BACKGROUND: The presence of chromosomal abnormalities could have a negative impact for human embryonic stem cell (hESC) applications both in regenerative medicine and in research. A biomarker that allows the identification of chromosomal abnormalities induced in hESC in culture before they take over the culture would represent an important tool for defining optimal culture conditions for hESC. Here we investigate the expression of CD30, reported to be a biomarker of hESCs with abnormal karyotype, in undifferentiated and spontaneously differentiated hESC.backslashnbackslashnMETHODS AND RESULTS: hESC were derived and cultured on mouse fibroblasts in KO-SR containing medium (serum free media) and passaged mechanically. Our results based on analysis at mRNA (RT-PCR) and protein (fluorescence-activated cell sorting and immunocytochemistry) level show that CD30 is expressed in undifferentiated hESC, even at very early passages, without any correlation with the presence of chromosomal anomalies. We also show that the expression of CD30 is rapidly lost during early spontaneous differentiation of hESC.backslashnbackslashnCONCLUSION: We conclude that CD30 expression in hESC cultures is probably a consequence of culture conditions, and that KO-SR may play a role. In addition, the expression of so-called 'stemness' markers does not change in undifferentiated hESC during long-term culture or when cells acquire chromosomal abnormalities. View Publication

Microelectrode material and cell culture medium have significant roles in the signal-to-noise ratio and cell well-being in in vitro electrophysiological studies. Here, we report an ion beam assisted e-beam deposition (IBAD) based process as an alternative titanium nitride (TiN) deposition method for sputtering in the fabrication of state-of-the-art TiN microelectrode arrays (MEAs). The effects of evaporation and nitrogen flow rates were evaluated while developing the IBAD TiN deposition process. Moreover, the produced IBAD TiN microelectrodes were characterized by impedance, charge transfer capacity (CTC) and noise measurements for electrical properties, AFM and SEM for topological imaging, and EDS for material composition. The impedance (at 1 kHz) of brand new 30 $\mu$m IBAD TiN microelectrodes was found to be double but still below 100 k$\Omega$ compared with commercial reference MEAs with sputtered TiN microelectrodes of the same size. On the contrary, the noise level of IBAD TiN MEAs was lower compared with that of commercial sputtered TiN MEAs in equal conditions. In CTC IBAD TiN electrodes (3.3 mC/cm2) also outperformed the sputtered counterparts (2.0 mC/cm2). To verify the suitability of IBAD TiN microelectrodes for cell measurements, human pluripotent stem cell (hPSC)-derived neuronal networks were cultured on IBAD TiN MEAs and commercial sputtered TiN MEAs in two different media: neural differentiation medium (NDM) and BrainPhys (BPH). The effect of cell culture media to hPSC derived neuronal networks was evaluated to gain more stable and more active networks. Higher spontaneous activity levels were measured from the neuronal networks cultured in BPH compared with those in NDM in both MEA types. However, BPH caused more problems in cell survival in long-term cultures by inducing neuronal network retraction and clump formation after 1-2 weeks. In addition, BPH was found to corrode the Si3N4 insulator layer more than NDM medium. The developed IBAD TiN process gives MEA manufacturers more choices to choose which method to use to deposit TiN electrodes and the medium evaluation results remind that not only electrode material but also insulator layer and cell culturing medium have crucial role in successful long term MEA measurements. View Publication

Recently, induced pluripotent stem cells (iPSCs) were established as promising cell sources for revolutionary regenerative therapies. The initial culture system used for iPSC generation needed fetal calf serum in the culture medium and mouse embryonic fibroblast as a feeder layer, both of which could possibly transfer unknown exogenous antigens and pathogens into the iPSC population. Therefore, the development of culture systems designed to minimize such potential risks has become increasingly vital for future applications of iPSCs for clinical use. On another front, although donor cell types for generating iPSCs are wide-ranging, T cells have attracted attention as unique cell sources for iPSCs generation because T cell-derived iPSCs (TiPSCs) have a unique monoclonal T cell receptor genomic rearrangement that enables their differentiation into antigen-specific T cells, which can be applied to novel immunotherapies. In the present study, we generated transgene-free human TiPSCs using a combination of activated human T cells and Sendai virus under defined culture conditions. These TiPSCs expressed pluripotent markers by quantitative PCR and immunostaining, had a normal karyotype, and were capable of differentiating into cells from all three germ layers. This method of TiPSCs generation is more suitable for the therapeutic application of iPSC technology because it lowers the risks associated with the presence of undefined, animal-derived feeder cells and serum. Therefore this work will lead to establishment of safer iPSCs and extended clinical application. View Publication

The functional characteristics were compared for acute myelogenous leukemia (AML) cells (native blasts and AML cell lines) cultured in three serum-free media (X-vivo 10, X-vivo 15, [Bio-Whitacker, Walkersville, MD] and StemSpan [Stem Cell Technologies, Vancouver, BC, Canada]) and in medium containing 10% inactivated fetal calf serum (FCS). For native AML blasts the following functions were compared: (1) autonomous and cytokine-dependent proliferation; (2) frequency of clonogenic cell; and (3) constitutive cytokine secretion. AML blast proliferation differed between patients independent of the culture medium used, and clonogenic cells were maintained after in vitro culture in all media. In contrast, constitutive cytokine secretion was higher for cells cultured in StemSpan and FCS-containing medium than for cells cultured in the X-vivo media. Native AML blasts incubated in StemSpan also showed a low frequency of apoptotic cells. The three serum-free media could also be used for long-term expansion of well-characterized AML cell lines, but the optimal medium for cell expansion and cytokine secretion differed between cell lines. We conclude that standardized serum-free culture conditions can be used for in vitro studies of native AML blasts and AML cell lines. View Publication

Metabolic labeling with stable isotopes is a prominent technique for comparative quantitative proteomics, and stable isotope labeling with amino acids in cell culture (SILAC) is the most commonly used approach. SILAC is, however, traditionally limited to simple tissue culture regimens and only rarely employed in the context of complex culturing conditions as those required for human embryonic stem cells (hESCs). Classic hESC culture is based on the use of mouse embryonic fibroblasts (MEFs) as a feeder layer, and as a result, possible xenogeneic contamination, contribution of unlabeled amino acids by the feeders, interlaboratory variability of MEF preparation, and the overall complexity of the culture system are all of concern in conjunction with SILAC. We demonstrate a feeder-free SILAC culture system based on a customized version of a commonly used, chemically defined hESC medium developed by Ludwig et al. and commercially available as mTeSR1 [mTeSR1 is a trade mark of WiCell (Madison, WI) licensed to STEMCELL Technologies (Vancouver, Canada)]. This medium, together with adjustments to the culturing protocol, facilitates reproducible labeling that is easily scalable to the protein amounts required by proteomic work flows. It greatly enhances the usability of quantitative proteomics as a tool for the study of mechanisms underlying hESCs differentiation and self-renewal. Associated data have been deposited to the ProteomeXchange with the identifier PXD000151. View Publication

For human embryonic stem cells (ESC) to be used in cell replacement therapies, they must be grown under good manufacturing conditions in a chemically defined medium that lacks animal proteins. This study examined the ability of a newly designed medium containing the plant-derived serum replacement VegetaCell and other reagents of human origin to support undifferentiated growth and pluripotency of human ESC. This medium was tested in several culture systems, using human fibroblasts as a feeder layer or Matrigel in a feeder-free culture. Even under the most stringent feeder-free conditions without conditioned medium, human ESC exhibited an undifferentiated morphology, expressed markers of undifferentiated cells, demonstrated high alkaline phosphatase activity and multilineage differentiation and retained a normal karyotype. Compared with human ESC grown in standard culture conditions, human ESC maintained in humanized VegetaCell medium show longer cell cycles and decreased cell death. The availability of an animal protein-free medium supplemented with the low-cost VegetaCell reagent expands the repertoire of media for culturing human ESC as well as induced pluripotent stem cells for drug testing and cell replacement therapy. View Publication

It has been known for over 20 years that foetal calf serum can induce hypertrophy in cultured cardiomyocytes but this is rarely considered when examining cardiomyocytes derived from pluripotent stem cells (PSC). Here, we determined how serum affected cardiomyocytes from human embryonic- (hESC) and induced pluripotent stem cells (hiPSC) and hiPSC from patients with hypertrophic cardiomyopathy linked to a mutation in the MYBPC3 gene. We first confirmed previously published hypertrophic effects of serum on cultured neonatal rat cardiomyocytes demonstrated as increased cell surface area and beating frequency. We then found that serum increased the cell surface area of hESC- and hiPSC-derived cardiomyocytes and their spontaneous contraction rate. Phenylephrine, which normally induces cardiac hypertrophy, had no additional effects under serum conditions. Likewise, hiPSC-derived cardiomyocytes from three MYBPC3 patients which had a greater surface area than controls in the absence of serum as predicted by their genotype, did not show this difference in the presence of serum. Serum can thus alter the phenotype of human PSC derived cardiomyocytes under otherwise defined conditions such that the effects of hypertrophic drugs and gene mutations are underestimated. It is therefore pertinent to examine cardiac phenotypes in culture media without or in low concentrations of serum. View Publication

The developmental potential of human ES cells makes them an important tool in developmental, pharmacological, and clinical research. For human ES cell technology to be fully exploited, however, culture efficiency must be improved, large-scale culture enabled, and safety ensured. Traditional human ES cell culture systems have relied on serum products and mouse feeder layers, which limit the scale, present biological variability, and expose the cells to potential contaminants. Defined, feeder-independent culture systems improve the safety and efficiency of ES cell technology, enabling translational research. The protocols herein are designed with the standard research laboratory in mind. They contain recipes for the formulation of mTeSR (a defined medium for human ES cell culture) and detailed protocols for the culture, transfer, and passage of cells grown in these feeder-independent conditions. They provide a basis for routine feeder-independent culture, and a starting point for additional optimization of culture conditions. View Publication

This report describes the establishment directly from normal preimplantation mouse embryos of a cell line that forms teratocarcinomas when injected into mice. The pluripotency of these embryonic stem cells was demonstrated conclusively by the observation that subclonal cultures, derived from isolated single cells, can differentiate into a wide variety of cell types. Such embryonic stem cells were isolated from inner cell masses of late blastocysts cultured in medium conditioned by an established teratocarcinoma stem cell line. This suggests that such conditioned medium might contain a growth factor that stimulates the proliferation or inhibits the differentiation of normal pluripotent embryonic cells, or both. This method of obtaining embryonic stem cells makes feasible the isolation of pluripotent cells lines from various types of noninbred embryo, including those carrying mutant genes. The availability of such cell lines should made possible new approaches to the study of early mammalian development. View Publication

PURPOSE: Experimental in vitro models including well-characterised cell lines can be used to identify possible new therapeutic targets for the treatment of osteosarcoma. Culture media including inactivated serum is often recommended for in vitro culture of osteosarcoma cells, but the serum component then represents a nonstandardised parameter including a wide range of unidentified mediators. To improve the standardisation we have investigated whether serum-free culture media can be used in experimental in vitro studies of osteosarcoma cell lines. METHODS: The seven osteosarcoma cell lines Cal72, SJSA-1, Saos-2, SK-ES-1, U2OS, 143.98.2, and KHOS-32IH were cultured in vitro in various serum-free media and media supplemented with 10% heat-inactivated fetal calf serum (FCS). RESULTS: Although proliferation often was relatively low in serum-free media (X-vivo 10, X-vivo 15, X-vivo 20, Stem Span SFEM), some cell lines (Cal72, KHOS-32IH, Saos-2) showed proliferation comparable with the recommended FCS-containing media even when using serum-free conditions. The optimal serum-free medium then varied between cell lines. We also compared 6 different FCS-containing media (including Stem Span with 10% FCS) and the optimal FCS-containing medium varied between cell lines. However, all cell lines proliferated well in Stem Span with FCS, and this medium was regarded as optimal for four of the lines. FCS could not be replaced by fatty acids or low density lipoprotein when testing the Stem Span medium. The release of a wide range of soluble mediators showed only minor differences when using serum-free and FCS-containing media (including Stem Span with and without FCS), and serum-free Stem Span could also be used for in vitro studies of mitogen-stimulated T cell activation in the presence of accessory osteosarcoma cells. The use of Stem Span with 10% FCS allowed the release of a wide range of chemokines by osteosarcoma cell lines (Cal72, SJSA-1), and the chemokine release profile was very similar to the fibroblast lines Hs27 and HFL1. CONCLUSIONS: Serum-free culture media can be used for in vitro studies of several osteosarcoma cell lines, but the optimal medium varies between cell lines and thus depends on: (i) the cell lines to be investigated/compared; (ii) the functional characteristic that is evaluated (proliferation, cytokine release); and (iii) whether coculture experiments are included. View Publication

A major goal of experimental and clinical hematology is the identification of mechanisms and conditions that support the expansion of transplantable hematopoietic stem cells. In normal marrow, such cells appear to be identical to (or represent a subset of) a population referred to as long-term-culture-initiating cells (LTC-ICs) so-named because of their ability to produce colony-forming cell (CFC) progeny for textgreater or = 5 weeks when cocultured with stromal fibroblasts. Some expansion of LTC-ICs in vitro has recently been described, but identification of the factors required and whether LTC-IC self-renewal divisions are involved have remained unresolved issues. To address these issues, we examined the maintenance and/or generation of LTC-ICs from single CD34+ CD38- cells cultured for variable periods under different culture conditions. Analysis of the progeny obtained from cultures containing a feeder layer of murine fibroblasts engineered to produce steel factor, interleukin (IL)-3, and granulocyte colony-stimulating factor showed that approximately 20% of the input LTC-ICs (representing approximately 2% of the original CD34+ CD38- cells) executed self-renewal divisions within a 6-week period. Incubation of the same CD34+ CD38- starting populations as single cells in a defined (serum free) liquid medium supplemented with Flt-3 ligand, steel factor, IL-3, IL-6, granulocyte colony-stimulating factor, and nerve growth factor resulted in the proliferation of initial cells to produce clones of from 4 to 1000 cells within 10 days, approximately 40% of which included textgreater or = 1 LTC-IC. In contrast, in similar cultures containing methylcellulose, input LTC-ICs appeared to persist but not divide. Overall the LTC-IC expansion in the liquid cultures was 30-fold in the first 10 days and 50-fold by the end of another 1-3 weeks. Documentation of human LTC-IC self-renewal in vitro and identification of defined conditions that permit their extensive and rapid amplification should facilitate analysis of the molecular mechanisms underlying these processes and their exploitation for a variety of therapeutic applications. View Publication

Human induced pluripotent stem cells (hiPSCs) secrete essential autocrine factors that are removed along with toxic metabolites when the growth medium is exchanged daily. In this study, after determining the minimum inhibitory level of lactic acid for hiPSCs, a medium refining system was constructed by which toxic metabolites were removed from used culture medium and autocrine factors as well as other growth factors were recycled. Specifically, about 87 % of the basic fibroblast growth factor and 80 % of transforming growth factor beta 1 were retained in the refined medium after dialysis. The refined medium efficiently potentiated the proliferation of hiPS cells in adherent culture. When the refining system was used to refresh medium in suspension culture, a final cell density of (1.1 ± 0.1) × 10(6) cells mL(-1) was obtained, with 99.5 ± 0.2 % OCT 3/4 and 78.3 ± 1.1 % TRA-1-60 expression, on day 4 of culture. These levels of expression were similar to those observed in the conventional suspension culture. With this method, culture medium refinement by dialysis was established to remove toxic metabolites, recycle autocrine factors as well as other growth factors, and reduce the use of macromolecules for the expansion of hiPSCs in suspension culture. View Publication

Human embryonic stem cells (hESCs) offer an inexhaustible supply of human somatic cell types through their ability to self-renew while retaining pluripotency. As such, hESC-derived cell types are important for applications ranging from in vitro modeling to therapeutic use. However, for their full potential to be realized, both the growth of the undifferentiated cells and their derivatives must be performed in defined culture conditions. Many research groups maintain hESCs using mouse embryonic fibroblasts (MEF) and MEF conditioned medium (CM). The use of murine systems to support hESCs has been imperative in developing hESC technology; however, they suffer from some major limitations including lack of definition, xenobiotic nature, batch-to-batch variation, and labor-intensive production. Therefore, hESC culture definition is essential if hESC lines, and their derivatives are to be quality assured and manufactured to GMP. We have initiated the process of standardizing hESC tissue culture and have employed two serum-free media: mTeSR (MT) and Stem Pro (SP). hESCs were maintained in a pluripotent state, for over 30 passages using MT and SP. Additionally, we present evidence that hESCs maintained in MT and SP generate equivalent levels of human hepatic endoderm as observed with CM. This data suggests that MT and SP are effective replacements for MEF-CM in hESC culture, contributing to the standardization of hESC in vitro models and ultimately their application. View Publication