Membrane sialoglycolipids emerging as possible signal transducers for lymphocyte stimulation.

Biotin hydrazide was attached covalently to the aldehyde groups produced by periodate oxidation of bovine brain gangliosides. These modified gangliosides were incorporated into mature rat thymocytes by incubation of the biotinyl gangliosides in the culture medium containing these cells. Avidin, which binds strongly to biotin, agglutinated and stimulated DNA synthesis in thymocytes containing the incorporated biotin-tagged gangliosides. Avidin has no mitogenic effect on normal thymocytes or on cells that incorporate unmodified gangliosides. With fluoresceinated avidin, the incorporated biotinyl gangliosides are shown to be laterally redistributed into patches and caps. These results imply that gangliosides may be involved in transmembrane communication during lymphocyte stimulation.