Dynabeads CD45 Beads are uniform, superparamagnetic beads (4.5-μm diameter) coated with a primary monoclonal mouse IgG2a antibody specific for all known isoforms of CD45, a membrane glycoprotein found on all human leukocytes. Dynabeads CD45 Beads can be used to easily and efficiently isolate or deplete CD45-positive cells from viscous samples such as whole blood and bone marrow in about 30 minutes. Isolated cells can then be used for downstream molecular or proteomic studies.

In cancer research, depletion of CD45+ cells is often used to enrich circulating epithelial tumor cells (CTCs) in liquid biopsy samples such as peripheral blood mononuclear cells (PBMC) and whole blood to obtain untouched and viable CTCs for detection and quantification studies. The untouched CTCs can be pelleted and lysed directly using the TaqMan Cells-to-CT Express Kit.

Benefits of Dynabeads CD45 Beads include:
• Efficient isolation of human leukocytes from whole blood or bone marrow
• Enrichment of viable and untouched CTCs by leukocyte depletion
• Automated script available for high throughput CTC enrichment on the KingFisher Apex instrument

Dynabeads-based enrichment of CTCs by CD45 depletion
For CTC enrichment, Dynabeads CD45 Beads are added to the PBMC sample under continuous mixing for 30 minutes to optimize the binding of the Dynabeads to the leukocytes. The sample is then placed on a DynaMag magnet for <2 minutes to separate the bead-bound leukocytes from the enriched CTCs. The supernatant containing the enriched CTCs is transferred to a new tube and the bead-bound leukocytes discarded. If enriching CTCs directly from whole blood, the red blood cells should be lysed prior to CD45 depletion. If the sample contains a lot of contaminating granulocytes, Dynabeads CD15 Beads can be added to improve the granulocyte depletion efficiency.

High throughput negative isolation of CTCs on KingFisher Apex purification system
Enrichment of circulating CTCs is a time-consuming process if working with many samples in parallel and can lead to increased manual handling errors. This can be avoided by automating the workflow using the KingFisher Apex purification system with 96 deep-well plates. With automation, high-throughput recovery of untouched CTCs can be achieved in ∼50 minutes after loading the sample and reagents into the plates. The resulting CTCs are viable and suitable for culture and downstream molecular or proteomic analysis.

Benefits of automated CTC enrichment using Dynabeads CD45 depletion include:
• Reduced hands-on time
• High reproducibility due to fewer manual handling errors
• Increased throughput
• Recovery of a heterogenous CTC population

Alternative positive isolation strategies for CTCs
If it is preferred to positively isolate CTCs for molecular downstream applications such as RT-qPCR, we recommend using Dynabeads Epithelial Enrich (EpCAM). To positively isolate bead-free CTCs for immunological applications such as cell culture or flow cytometry, we recommend using Dynabeads CELLection Epithelial Enrich (EpCAM). If you are using your own biotinylated antibody, we recommend using Dynabeads MyOne Streptavidin T1.

Commercial supply
Our manufacturing sites are ISO 13485-certified. Bead characteristics and manufacturing conditions help ensure consistency and batch reproducibility making them well suited for commercial supply. If you are in the process of customizing Dynabeads CD45 Beads in a commercial product or service or need a larger bulk volume of this product, please contact us at oemdynal@lifetech.com or read more on our Dynabeads OEM page.