Background Primary B cells are an important target for investigation and transfection of B cells is considered difficult. Electroporation is a very useful technology for transfection but its application on B cells has been unsatisfactory with low efficiency and low viability. The first reason is the small size of B cells compared to cell lines and the second reason is the low abundance of B cells in human PBMC. Since we had previous exprience with T cell electroporation, we sought to extend our knowledge on electroporation to B cells.

Methods Here we studied the B cell electroporation in PBMC samples and found that it is preferrable to electroporate the B cells in the PBMC mixture and B cells can be purified after electroporation if necessary. In this fashion, the total cell number in electroporation is boosted by other cell types in the PBMC and it helps B cell electroporation. Furthermore, we studied expanded B cells and found that they have a larger size than unstimulated B cells and the size increase is correlated to a decrease in electroporation voltage, consistent with the electroporation principle that larger cells need a lower voltage.

Results When B cells are expanded, the electroporation efficiency is similar to common cell lines and it becomes easy to do gene expression or genomic modification.

Conclusions Our studies elucidated the mechanism of difference between unstimulated B cells and expanded B cells and could be useful in helping the research on B cells.