Properties of bispecific rosette-forming cells. I.--Presence of T-lymphocyte markers.

Three T-cell markers have been used to determine the origin of bispecific rosette forming cells (RFC) observed after stimulation by two species of heterologous red cells. The inhibition by anti-theta serum (AOS), azathioprine (AZ) and anti-lymphocyte serum (ALS) of the majority of bispecific RFC indicates their T-cell origin. The study of their sensitivity to these inhibitors suggested that about half of the bispecific RFC belong to immature T1 cell subset and the other half to more mature T2 cells. Conversely, monospecific RFC include both B-celle RFC have characteristics different from monospecific RFC argues against the reaction of double RFC against a common antigenic determinant of the two erythrocyte types.