A rosette technique for identification of human mononuclear cells bearing Fc receptors

A rosette technique has been described which showed some human mononuclear cells to bind chicken red blood cells coated with rabbit anti-chicken erythrocyte antibodies (EA). Intact 7S Ig, but not their F(ab')2 fragments, were found to sensitize chicken erythrocytes; therefore it was concluded that this rosette technique detects cells bearing receptors for the Fc portion of IgG. Among the different parameters of the reaction which were studied, centrigugation at 4 degrees C appeared necessary for obtaining the maximum number of rosettes. Kinetics of rosette dissociation indicated low and heterogeneous binding avidities. Distribution of EA-rosette forming cells among different organs appeared extremely heterogeneous: 8-28% were found in blood, spleen and bone marrow, whereas about 3% were found in lymph nodes and less than 1% in tonsils and thymus; this suggests that EA-rosette forming cells are not restricted to a single subclass of either T or B lymphocytes.