Use of magnetic cell sorting to isolate blood neutrophils from rats

The difficulty in obtaining sufficient numbers of neutrophils from rat blood limits the usefulness of this species in studies involving neutrophil function. To increase the neutrophil yield from rats drinking alcohol on a long-term basis, which further decreases neutrophil yield, we developed a magnetic cell-sorting technique. The rats were exsanguinated and neutrophils were isolated, using either traditional density gradient centrifugation or magnetic cell sorting. In the latter method, the leukocytes were labeled with biotinylated anti-rat granulocyte antibodies, followed by addition of streptavidin-conjugated superparamagnetic microbeads. The labeled cell suspension was applied to a steel wool column suspended within a magnetic field. Unlabeled cells were washed through the column. Retained, labeled neutrophils were eluted after the column was removed from the magnetic field. Compared with density gradient centrifugation, magnetic cell sorting yielded two- to fivefold higher neutrophil numbers per rat with increased purity. Viability was comparable for neutrophils isolated by the two techniques. Magnetic cell sorting is a rapid, gentle method for isolation of rat blood neutrophils and enhances the potential usefulness of rats in neutrophil-related research.