Characterization of thymus‐derived and bone marrow‐derived rosette‐forming lymphocytes

Abstract

Abstract An improved technique has been developed to accurately quantitate lymphoid rosette‐forming cells (RFC) and to assess the morphology and antigen‐binding ability of each RFC. Two essential features were involved. First, rosettes were fixed with glutaraldehyde (a concentration of 0.6 % minimized the formation of artefacts). This fixation prevented dissociation of rosettes; RFC of weak antigen‐binding ability could therefore consistently be preserved. Second, rosette preparations were stained, thus permitting morphological classification of RFC and the elimination of false rosettes. The antigen‐binding ability of each RFC was determined by the number of sheep red blood cells (SRBC) bound. By this technique, thymus‐derived (T) RFC were found to bind fewer erythrocytes than bone marrow‐derived (B) RFC. Pretreatment of the SRBC with neuraminidase increased the SRBC‐binding ability of B RFC, thus making the latter readily distinguishable from T RFC. Functionally different subpopulations of T and B RFC were suggested.