A new method for the simultaneous assay of rosette-forming and antibody-secreting cells, utilising immune adhesion reactions in monolayer.

Mixtures of sheep erythrocytes and immune spleen cells from mice were incubated in shallow slide chambers coated with erythrocyte ghosts or anti-mouse Ig, with poly L-lysine as a coupling agent. Antigen-binding cells and erythrocytes surrounding antibody-releasing lymphocytes became bound to the reactive surfaces by immunocytoagglutination and could be readily observed on inversion of the chambers. The sensitivity of the method compares with those currently in use for quantification of antibody-releasing cells, and resolution of rosettes is markedly superior to that obtainable in other assay systems. The advantages and limitations of the method are discussed.