Lymphocyte subpopulations in man: ox erythrocytes as indicators in the EA- and EAC-rosette tests: serological and technical aspects

Serological properties of ox erythrocytes (ORBC) make it possible to select cells which exhibit weak agglutinability despite strong antibody sensitization. This property and the non-binding of unsensitized ORBC to lymphocyte surface membranes make these cells excellently suited as indicators in techniques for the identification of erythrocyte-antibody (EA) and erythrocyte-antibody-complement (EAC) rosette-forming lymphocytes (RFC). This report describes the relevant serology for the selection of appropriate cells and antisera. Further, some of the technical aspects of these tests are discussed. A simple method for the sensitization of ORBC with complement is described. The basis for this method is the naturally occurring complement-binding anti-ORBC antibodies of the IgM class in human sera. After zymosan treatment the sera are deficient in the fifth component of complement and hence non-haemolytic, which make these sufficient as sensitizing agents in the preparation of EAC indicator cells. The relations of EA- anc EAC-RFC to be established T and B lymphocyte subpopulations are revealed by the enrichment and depletion of lymphocytes rosetting with 2-aminoethylisothiouronium bromide (AET)-treated sheep erythrocytes (SRBC).