Exposure by phospholipase A of receptors for sheep erythrocytes on human B cells

Abstract

HUMAN T lymphocytes are known to form rosettes (Erosettes) with certain specific xenogeneic erythrocytes, including sheep erythrocytes (SRBCs). This rosette formation has been widely used as a specific marker for T cells and valuable information has been obtained^1–3. There is, however, increasing evidence that multiple factors influence the rosette formation; some of these factors can be related to an external effect^4,5 or to the active cell metabolism^6,7, whereas others are more intimately related to the processes operating during cell maturation⁸. Further, the presence of lymphoid cells carrying E rosette receptors, as well as markers for B cells, has been demonstrated⁹. It has also been demonstrated that neuraminidase treatment induced E rosette formation in a population of lymphocytes bearing B-cell characteristics¹⁰. Thus, it has not yet been established whether the ‘presence of receptor’ for E rosette is specific for T cells or not. For this reason, an elucidation of the factors that influence the receptor activity is important if the exact nature of the receptor and the population of cells with it is to be clarified. In the course of investigations on such factors, we have found that treatment of the cells with phospholipase A (PLA) from cobra venom induced the ability to form E rosette in human lymphoblastoid cells that are known to be B-cell line. The study also indicated that a population of presumed B cells from the peripheral blood also formed rosettes after such treatment.