Cell separation by staphylococcal protein A-coated erythrocytes.

A method for cell separation according to cell surface markers is described. Heat-aggregated human IgG or IgG antibodies, raised to surface markers of mouse lymphocytes-for example, Ig or theta antigen-are allowed to react with the lymphocytes. When these cells are incubated with sheep erythrocytes coated with protein A of Staphylococcus aureus, rosettes are formed. These rosettes can be separated from nonrosetted lymphocytes by density gradient centrifugation. The erythrocytes of the rosettes are disrupted by complement action or by osmotic shock, and the lymphocytes are recovered. Immunoglobulin-protein A complexes are shed off the cell surfaces by cultivation. In this way cells with, as well as those without, surface markers could be obtained with high purity (up to 80%) and with high viability.