New look, same high quality and support! You may notice that your instrument or reagent packaging looks slightly different from images displayed on the website, or from previous orders. We are updating our look but rest assured, the products themselves and how you should use them have not changed. Learn more
Figure 1. Typical EasySep™ Human B Cell Isolation Profile
Starting with human PBMCs, the B cell (CD3-CD19+) content of the isolated fraction is typically 95.1 ± 1.4% (mean ± SD). In the example above, the final purities of the start and isolated fractions are 4.5% and 94.9%, respectively.
Can EasySep™ be used for either positive or negative selection?
Yes. The EasySep™ kits use either a negative selection approach by targeting and removing unwanted cells or a positive selection approach targeting desired cells. Depletion kits are also available for the removal of cells with a specific undesired marker (e.g. GlyA).
How does the separation work?
Magnetic particles are crosslinked to cells using Tetrameric Antibody Complexes (TAC). When placed in the EasySep™ Magnet, labeled cells migrate to the wall of the tube. The unlabeled cells are then poured off into a separate fraction.
Which columns do I use?
The EasySep™ procedure is column-free. That's right - no columns!
How can I analyze the purity of my enriched sample?
The Product Information Sheet provided with each EasySep™ kit contains detailed staining information.
Can EasySep™ separations be automated?
Yes. RoboSep™, the fully automated cell separator, automates all EasySep™ labeling and cell separation steps.
Can EasySep™ be used to isolate rare cells?
Yes. We recommend a cell concentration of 2x108 cells/mL and a minimum working volume of 100 µL. Samples containing 2x107 cells or fewer should be suspended in 100 µL of buffer.
Are the EasySep™ magnetic particles FACS-compatible?
Yes, the EasySep™ particles are flow cytometry-compatible, as they are very uniform in size and about 5000X smaller than other commercially available magnetic beads used with column-free systems.
Can the EasySep™ magnetic particles be removed after enrichment?
No, but due to the small size of these particles, they will not interfere with downstream applications.
Can I alter the separation time in the magnet?
Yes; however, this may impact the kit's performance. The provided EasySep™ protocols have already been optimized to balance purity, recovery and time spent on the isolation.
For positive selection, can I perform more than 3 separations to increase purity?
Yes, the purity of targeted cells will increase with additional rounds of separations; however, cell recovery will decrease.
How does the binding of the EasySep™ magnetic particle affect the cells? is the function of positively selected cells altered by the bound particles?
Hundreds of publications have used cells selected with EasySep™ positive selection kits for functional studies. Our in-house experiments also confirm that selected cells are not functionally altered by the EasySep™ magnetic particles.
If particle binding is a key concern, we offer two options for negative selection. The EasySep™ negative selection kits can isolate untouched cells with comparable purities, while RosetteSep™ can isolate untouched cells directly from whole blood without using particles or magnets.
Construction and characterization of chimeric FcγR T cells for universal T cell therapy
Experimental Hematology & Oncology 2025 Jan
Abstract
BackgroundSeveral approaches are being explored for engineering off-the-shelf chimeric antigen receptor (CAR) T cells. In this study, we engineered chimeric Fcγ receptor (FcγR) T cells and tested their potential as a versatile platform for universal T cell therapy.MethodsChimeric FcγR (CFR) constructs were generated using three distinct forms of FcγR, namely CD16A, CD32A, and CD64. The functionality of CFR T cells was evaluated through degranulation assays, specific target lysis experiments, in vitro cytokine production analysis, and assessment of tumor xenograft destruction specificity in mouse models using different monoclonal antibodies (MoAbs).ResultsThree types of CFR T cells were engineered, 16s3, 32-8a, 64-8a CFR T cells. In the presence of rituximab (RTX), cytotoxicity of all three types of CFR T cells against CD20+ Raji-wt, K562-CD20+, and primary tumor cells was significantly higher than that of the mock T cells (P < 0.001). When herceptin was used, all three types of CFR T cells exhibited significant cytotoxicity against HER2+ cell lines of SK-BR-3, SK-OV-3, and HCC1954 (P < 0.001). The cytotoxicity of 64-8a CFR T cells was significantly inhibited by free human IgG at a physiological dose (P < 0.001), which was not observed in 16s3, 32-8a CFR T cells. Compared to 32-8a CFR T cells, 16s3 CFR T cells exhibited more prolonged cytotoxicity than 32-8a CFR T cells (P < 0.01). In in vivo assays using xenograft models, 16s3 CFR T cells significantly prolonged the survival of mice xenografted with Raji-wt cells in the presence of RTX (P < 0.001), and effectively reduced tumor burden in mice xenografted with SK-OV-3 cells in the presence of herceptin (P < 0.05). No significant non-specific cytotoxicity of CFR T cells was found in vivo.ConclusionThe anti-tumor effects of the CFR T cells in vitro and in xenograft mouse models are mediated by specific MoAbs such as RTX and herceptin. The CFR T cells therefore have the features of universal T cells with specificity directed by MoAbs. 16s3 CFR T cells are chosen for clinical trials.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40164-025-00595-x.
Telomemore enables single-cell analysis of cell cycle and chromatin condensation
Nucleic Acids Research 2025 Jan
Abstract
Single-cell RNA-seq methods can be used to delineate cell types and states at unprecedented resolution but do little to explain why certain genes are expressed. Single-cell ATAC-seq and multiome (ATAC + RNA) have emerged to give a complementary view of the cell state. It is however unclear what additional information can be extracted from ATAC-seq data besides transcription factor binding sites. Here, we show that ATAC-seq telomere-like reads counter-inituively cannot be used to infer telomere length, as they mostly originate from the subtelomere, but can be used as a biomarker for chromatin condensation. Using long-read sequencing, we further show that modern hyperactive Tn5 does not duplicate 9 bp of its target sequence, contrary to common belief. We provide a new tool, Telomemore, which can quantify nonaligning subtelomeric reads. By analyzing several public datasets and generating new multiome fibroblast and B-cell atlases, we show how this new readout can aid single-cell data interpretation. We show how drivers of condensation processes can be inferred, and how it complements common RNA-seq-based cell cycle inference, which fails for monocytes. Telomemore-based analysis of the condensation state is thus a valuable complement to the single-cell analysis toolbox.
Immune counter-evolution: immortalized B cell clones can undergo ex vivo directed evolution to counteract viral escape
C. Marsman et al.
Frontiers in Immunology 2025 Aug
Abstract
IntroductionAmid the persistent threat of future pandemics, the continuous evolution of SARS-CoV-2 exposed critical challenges for vaccine efficacy and therapeutic interventions, highlighting the need for rapid and adaptable approaches to respond to immune escape variants.MethodsHere, we report the use of immortalized B cell libraries from human peripheral blood mononuclear cells (PBMCs) and tonsil tissues to uncover B cell clones exhibiting cross-reactive neutralization against various SARS-CoV-2 variants and perform directed evolution of immortalized B cell clones to produce antibodies with improved binding and neutralization against emerging SARS-CoV-2 variants.ResultsImmortalization of PBMC and tonsil-derived human B cells was achieved through transduction with retroviral vectors encoding apoptosis inhibitors, yielding transduction efficiencies of 67.5% for PBMCs and 50.2% for tonsil-derived cells. Analysis revealed that immortalized B cell libraries produced with this method retain diverse immunoglobulin isotype representations. Through high-throughput functional screening of approximately 40,000 B cells per library, we identified 12 unique clones with neutralization activity for SARS-CoV-2, leading to selection of monoclonal antibodies with robust neutralization activity against Delta and BA.5 variants. We applied our directed evolution approach to libraries generated by ex vivo AID-induced somatic hypermutation (SHM) of immortalized B cell clones to enhance the affinity and cross-reactivity, resulting in improved binding and neutralization potency to escape variants such as EG.5.1 and JN.1. Furthermore, we engineered a bi-paratopic antibody combining KBA2401, a broadly neutralizing antibody binding to highly conserved epitope on Spike-RBD, and KBA2402, a broadly binding non-neutralizing antibody, resulting in enhanced potency against SARS-CoV-2 variant JN.1 and KP.3.DiscussionOur findings illustrate the use of immortalized B cell libraries for development of therapeutics that adapt to viral evolution and highlight the application of ex vivo directed evolution in refining antibody responses against emerging immune escape SARS-CoV-2 variants. The approach here described offers a promising pathway for rapid therapeutic development in the face of evolving viral threats.
Thank you for your interest in IntestiCult™ Organoid Growth Medium (Human). Please provide us with your contact information and your local representative will contact you with a customized quote. Where appropriate, they
can also assist you with a(n):
Estimated delivery time for your area
Product sample or exclusive offer
In-lab demonstration
By submitting this form, you are providing your consent to STEMCELL Technologies Canada Inc. and its subsidiaries and affiliates (“STEMCELL”) to collect and use your information, and send you newsletters and emails in accordance with our
privacy policy. Please contact us with any questions that you may have. You can unsubscribe or change your email preferences at any time.
EasySep™小鼠TIL（CD45）正选试剂盒
沪公网安备31010102008431号