Hello Erica Weber

Did you mean that plasma cells and plasmablasts have specific markers like CD138 and not DC138?

CD138 is a marker for plasma cells, but not plasmablasts. Plasmablasts are more likely to express CD19 and CD20, while plasma cells are CD19- and CD20-. Plasmablasts, which are precursor cells to plasma cells, have lower levels of CD138 expression.

The primary marker used to isolate memory B cells is CD27. While CD27 is a strong indicator, it is important to note that CD27-negative memory B cells also exist. Other markers like the CD19 can be used in conjunction with CD27 for more precise B cell subset identification.

You may want to refer to the paper attached below for the isolation of CD27-positive human memory B cells.

https://academic.oup.com/jimmunol/article-abstract/198/Supplement_1/144.2/7970031?redirectedFrom=fulltext

The details of the commercial kits available for the isolation of human memory B cells may be found in the links provided below.

https://www.miltenyibiotec.com/IN-en/products/memory-b-cell-isolation-kit-human.html

https://www.stemcell.com/products/easysep-human-memory-b-cell-isolation-kit.html#section-protocols-and-documentation

Best,

Yes, memory B cells can be isolated using specific surface markers, though it’s a bit more complex than isolating plasma cells.

Common markers for memory B cells:

• CD19+ – General B cell marker
• CD27+ – A key marker for memory B cells
• IgD− or IgM− – Often used to distinguish memory from naïve B cells
• CD38low – Helps exclude plasmablasts and activated B cells
• CD138− – To exclude plasma cells

So, a typical memory B cell phenotype would be: CD19+ CD27+ IgD− CD38low CD138−

Are there commercial kits?

Yes, several companies offer commercial kits or antibody panels for isolating memory B cells, either by:

• Magnetic-activated cell sorting (MACS) – e.g., Miltenyi Biotec
• Fluorescence-activated cell sorting (FACS) – for more precise isolation

Miltenyi, STEMCELL Technologies, and BioLegend are some of the companies that provide reagents or pre-defined protocols for isolating memory B cells from blood or PBMCs.

Hello,

I just wanted to add to Yaying Pan's answer which mentioned CD38 - CD38 tends to be upregulated on germinal centre B cells in humans, but mouse B cells downregulate CD38 when they enter the germinal centre.

For mouse memory B cells, the surface phenotype (if sorting by FACS) could include CD138- CD19+ B220+ IgD− CD38+ (and bait-specific cells depending on the model).

Also note if you do use any of the magnetic purification kits, you could consider adding commercially sourced antibodies if they aren't included in the kit (such as IgD to remove IgD+ cells and improve the purity).