Electron microscope study on human lymphocyte-sheep erythrocyte rosettes

Nonimmune rosette formation of human peripheral blood lymphocytes and cultered MOLT 3 and MOLT 4 cells with sheep red blood cells was studied by transmission electron microscopy. At the cell contact area of the rosette, lymphoid and red cell membranes were parallel and 80-100 A apart. The inner leaflet of the lymphoid cell membrane seemed denser, and amorphous substance attached to its cytoplasmic face. The cell contact area was 100-1000 nm wide and frequently on the lymphoiid cell body rather than on microvilli, though some cells extended microvilli near red cells.