I prefer the RosetteSep assay from Stemcell Technologies - the kit is a bit expensive, but avoids beads completely and gives a pretty good yield/purity

Hi Abdullah,

It really comes down to how pure you want your monocytes. Using a negative selection method will help ensure that your monocytes are not potentially activated, but positive selection will typically give you a more pure monocyte population. I use Miltenyi's CD14 paramagnetic microbeads to routinely to isolate monocytes via positive selection and don't have any activation issues for the assays I perform. In fact, I use Miltenyi's microbeads for most of my positive/negative selections, for the very reason that they don't typically activate my cells of interest - this is largly due to the fact that Miltenyi's beads are considerably smaller (

You can use the Miltenyi's "Monocyte Isolation Kit II" which indirectly isolates untouched monocytes from human PBMCs. I used this kit and it works well. However, using this negative selection you lose the CD16+ monocyte subpopulation. It depends on what kind of study you intend to do.

Dear Charles and Daniela, Thanks for scientific suggestions.

Hi,

I have used Miltenyi and StemCell reagents without any functional differences in the downstream application. Thanks to Daniela Latorre's comment on CD16+ monocytes. Currently, human monocytes are defined as CD14+CD16- classical, CD14+CD16+ transitional and CD14-D16+CD56- non-classical monocytes (i.e., inflammatory monocytes).

Hi All,

I Had a conversation with someone from MiltineyiBiotech over phone. According to her, monocytes loose CD14 following positive selection. The lady suggested that for microarray experiments it is better to choose negative selection otherwise loosing CD14 following isolation, it does not affect anything downstream application.