Dear Mónica Itzel Martínez Gutiérrez

I briefly wanted to reach out concerning your inquiry. I had very good results with the negative selection kits for B cells from Miltenyi, irrespective if you use mice or humans as per:

Article Isolation of B-cells using Miltenyi MACS bead isolation kits

They do provide nice yields for healthy, non-immunocompromised individuals in the paper.

You may also consider density gradient centrifugation for PBMC isolation, as per:

Article Optimization of Peripheral Blood Mononuclear Cell Extraction...

If you use the optimized protocol as an estimate you can expect 10 M cells/ per 10 mL blood (with up to 20 M being possible). In circulation you will have between 10-20% B cells, which should yield on ca. 1 M B cells per healthy individual and (and in the absolute best case 4 M B cells) per 10 mL blood. Again, these are ballpark numbers, which strongly depend on the health status of your study individuals.

For mice, please check the attached papers (for protocols, stimulation and functional readouts.

Article MYSM1-dependent checkpoints in B cell lineage differentiatio...

Article Regulation of B Lymphocyte Development by Histone H2A Deubiq...

All the best & good luck with your experiment!

Michael