Human T and B lymphocyte rosette tests: Effect of enzymatic modification of sheep erythrocytes (E) and the specificity of neuraminidase-treated E

Sheep erythrocytes (E) were treated with papain or neuraminidase to evaluate what effect these enzymes would have on the E rosette test for human T lymphocytes. Few or no rosettes were detected with sheep erythrocytes treated with papain (E_P). Sensitization of E_P with rabbit antibody and mouse complement resulted in a rosette indicator (E_PAC) which could be used to detect peripheral blood complement receptor lymphocytes (CRL) and thymocyte CRL without having to perform the rosette assay at 37 °C. Neuraminidase treatment of E (E_N) enabled the detection of approximately 20% more rosette-forming cells (RFC) in human peripheral blood lymphocyte (PBL) suspensions compared to untreated E. Rosette studies on a patient with severe combined immunodeficiency disease and on human lymphoblastoid cell lines showed that the additional rosettes detected with E_N were T lymphocytes.