Modification of blood-borne arrest properties of lymphoma cells by inhibitors of protein glycosylation suggests the existence of endogenous lectins.

The requirement for intact carbohydrates of glycoproteins at the cell surface was investigated after treatment of lymphoma cells with compounds which interfere at different steps in N-linked glycosylation: swainsonine and 1-deoxynojirimycin act at different levels during the processing, so that complex oligosaccharides cannot be formed; 2-deoxyglucose, beta-hydroxynorvaline, and tunicamycin completely prevent the formation of N-linked (high-mannose as well as complex) oligosaccharides. The role of sialic acid was investigated by treating the cells with neuraminidase. These treatments resulted in altered patterns of surface-labelled glycoproteins after SDS-polyacrylamide gel electrophoresis. Blood-borne arrest of lymphoma cells in the spleen was sensitive to neuraminidase and to treatments interfering with the processing of complex N-linked oligosaccharides. It is suggested that carbohydrates are signals for cellular interactions involved in the recirculation and homing behaviour of lymphoid cells and probably interact with endogenous lectins at their site of homing.