Binding of Sheep Erythrocytes to Human Lymphocytes

The study concerned the binding of sheep red blood cells by human peripheral blood lymphocytes. The results indicate that the phenomenon (rosette formation) is probably dependent on thymus‐derived lymphocytes (T lymphocytes) and not due to bone marrow lymphocytes (B lymphocytes). These data were obtained by a gradient centrifugation technique separating B lymphocytes from rosette‐forming cells, by direct study of B lymphocytes and rosette‐forming cells in the same preparations, and from the study of patients with selective immunodeficiency diseases and chronic lymphocytic leukaemia. Furthermore, inhibition of rosette formation was absent or very weak after incubation of lymphocytes with anti‐immunoglobulin antisera, but considerable following their incubation with unspecific mitogens (phytohaemagglutinin, pokeweed mitogen, concanavalin A, anti‐lymphocyte antiserum) and also after trypsin treatment. Incubation temperature was important for the frequency of rosettes, and experiments with metabolic inhibitors showed that to form rosettes the lymphocytes required an intact energy production.