High-yield purification of rat monocytes by combined density gradient and immunomagnetic separation.

Satisfactory purification of rodent monocytes in suspension has not been achieved up to now because in rats and mice these cells occur as a minor population of peripheral blood leukocytes overlapping with lymphocytes in size and density. We describe a two-step procedure for the isolation of monocytes from rat blood with high yield and purity. This method permits the recovery of more than 90% of monocytes collected by perfusion of the vasculature and avoids loss of major subpopulations. Percoll density gradient centrifugation of perfusate cells is combined with subsequent indirect immunomagnetic depletion of lymphocytes using an antibody cocktail. The method described produces more than 90% pure rat monocytes.