Studies on human T lymphocyte rosette formation with human and sheep erythrocytes

A large proportion of normal human blood lymphocytes forms rosettes with neuraminidase-treated autologous and allogeneic human erythrocytes (nHRBC) or sheep red blood cells (SRBC). In contrast, the percentage of rosette-forming cells is extremely reduced in the peripheral blood of patients with chronic lymphocytic leukemia. The formation of mixed rosettes after addition of nHRBC and SRBC suggests that most normal rosette-forming lymphocytes have receptor sites for both types of erythrocytes. Rosette formation with neuraminidase-untreated HRBC occurs only with a small fraction of normal lymphocytes, but can be increased by preincubating the lymphocytes with neuraminidase. Similar to rosette formation with SRBC. the binding of nHRBC is temperature-dependent, is prevented by pretreatment of the lymphocytes with proteolytic enzymes, but is not inhibited by EDTA. Rosette dissociation during incubation at 37 degree C is accompanied by conversion of ring- or morula-like rosettes into horseshoes or caps.