Spontaneous rosette formation by mouse L cells.

Mouse fibroblasts form spontaneous rosettes with sheep erythrocytes and with red cells from several other species. They do not form C3 or Fc rosettes, and they do not bind small amounts of aggregated gammaglobulin. Spontaneous rosette formation is maximum at 37 degress and minimum at 4 degrees. The reaction is complete in 30 min. Antisera to fibroblast membrane components do not inhibit rosette formation. Rosetting is inhibited by fixation of the cells with formaldehyde or glutaraldehyde as well as by killing with phenol or by prolonged incubation with sodium azide. The rosette reaction is inhibited by vinblastine but not by cytochalasin B. From these data on the kinetics, temperature and drug sensitivities it is suggested that T cells and fibroblasts form spontaneous rosettes by different mechanisms.