Glycolipid and p 40 are the binding sites in the sheep erythrocyte and T-lymphocyte membrane responsible for rosette formation.

By coupling the major glycoprotein and total glycolipid of the sheep erythrocyte membrane to agarose beads it could be demonstrated that only lipid-beads formed rosettes with peripheral blood lymphocytes. Lipid-beads and sheep erythrocytes formed double rosettes with peripheral blood lymphocytes. Trypsinization of lymphocytes destroyed the rosette formation with lipid-beads. Subfractionation of the lipid by thin-layer chromatography revealed 8 different subfractions, 3 of them when coupled to agarose beads showed rosette formation. When the lipid was coupled to radioactive albumin, a protection of molecular weight 40,000 was labeled in two T-lymphocyte plasma membranes but not in B-lymphocyte plasma membranes. It is concluded that a lipid-protection interaction, involving the lipid of the erythrocyte and the p40 of the lymphocyte membrane, is responsible for rosette formation of T-lymphocytes.