To begin, divide the purified, undiluted mouse CNS cell suspension into two fractions for further isolations of microglia and oligodendrocytes. Then add magnetically labeled microbead specific for the surface antigen for different CNS cell types to the respective cell suspension. Place the column in the magnetic field, equate the column, and then add the resulting cell suspension onto the column.
Magnetically labeled cells will be retained within the column, and unlabeled cells will run through. After removing the column from the magnetic field, flush out magnetically labeled cells from the column into a tube as the positively selected cell fraction. Divide the negative flow through from the oligodendrocytes into two fractions for the further isolations of neurons and astrocytes.
Flow cytometry analysis using cell type specific markers combined with live or dead cell discrimination yielded microglia, oligodendrocytes, astrocytes, and neurons. Phenotypic characterization of the different cell populations proved that single cell suspensions with approximately 90%purity and viability were obtained for all main CNS resident cell types.