Rosette formation by canine peripheral blood lymphocytes

The surface membrane characteristics of canine peripheral blood lymphocytes were investigated using erythrocyte (E) and erythrocyte antibody complement (EAC) rosette assays and immunofluorescent staining techniques. Canine thymus-derived lymphocytes formed nonimmune E rosettes with human and guinea pig erythrocytes at approximately the same percentages (mean percentage 36.3 and 32.4, respectively). Rosettes did not form with erythrocytes from seven other animal species. Cell surface immunoglobulins were demonstrable in a small percentage (4%) of the E rosette-forming lymphocyte population. Fragments of human erythrocytes inhibited E rosette formation by intact human red cells, but did not result in a significant decrease in rosette formation by intact guinea pig erythrocytes; likewise, guinea pig fragments had no inhibitory effect on rosette formation by human erythrocytes, demonstrating that separate receptors were required for the two red cell types. EAC rosette formation was not affected by addition of intact or fragmented human and guinea pig erythrocytes. Canine bone marrow-derived lymphocytes were characterized by immunoglobulin on the cell surface and EAC rosette formation. Serial tests of lymphocytes from one dog revealed a wide variation in percentage of cells forming E and EAC rosettes. A close correlation was observed between the immunoglobulin-bearing cells (mean percentage 46.6) and those forming EAC rosettes (mean percentage 49.3).