BINDING OF IMMUNOGLOBULIN CLASSES TO SUB-POPULATIONS OF HUMAN RED-BLOOD-CELLS SEPARATED BY DENSITY-GRADIENT CENTRIFUGATION

  • 1 January 1980
    • journal article
    • research article
    • Vol. 55  (5) , 817-822
Abstract
Human erythrocytes (RBC) from whole blood were separated according to their specific densities by centrifugation on a polyvinyl-pyrrolidine-coated colloidal silica matrix (Percoll) into 4 major subpopulations. By indirect immunofluorescence assay the most dense RBC subpopulation, with specific density greater than 1.110 g/ml (3-5% of total RBC), was positive for membrane-bound immunoglobulin [Ig]; the remaining, less dense subpopulations were negative. IgG was present on 85-95%, IgM on 28-32% and IgA on 15-20% of the RBC in the most dense population. When these Ig were eluted, radiolabeled and used in binding studies with autologous RBC fractions subjected to thermal and/or enzymatic treatment, they reacted specifically with the less dense RBC subpopulations. Previously cryptic antigens were apparently revealed by the activity of neuraminidase on plasma membranes of the treated RBC.