Human autologous rosette-forming cells. II. Specificity of the binding between lymphocytes and erythrocytes.

The relationship between autorosettes and allorosettes was investigated using a mixed rosette assay in which the origin of the erythrocytes was assessed by the fluorescein isothiocyanate (FITC) labeling of one type of erythrocyte. The data show that auto- and allorosettes belong to the same T-cell subset: in most of the subjects, the percentages of T cells binding autologous red blood cells (auto-RBC) are equivalent to those binding allogeneic RBC (allo-RBC); the percentage of rosettes formed after the simultaneous addition of auto- and allo-RBC is similar to that of autorosettes alone or allorosettes alone; and nearly 80% of the rosetting cells bind both types of RBC as directly visualized in the mixed rosette assay. The experiments in which the lymphocytes are rosetted first with one type of RBC, and then with the other type support the finding that auto- and allo-RBC may bind to the lymphocytes through a single receptor which exhibits a varying affinity for RBC according to their origin.