Dog erythrocyte rosette-forming lymphocyte: blockage by OKT11 monoclonal antibody.

Human peripheral blood mononuclear cells (PBM) were separated into sheep erythrocyte rosette-forming (Es+) and non Es+ cells by the Ficoll-Hypaque gradient sedimentation method. Thirty-eight percent of the Es+ cells formed rosettes with dog erythrocytes and were designated as Es+Ed+ cells. The remaining Es+ cells were designated as Es+Ed- cells. Only a few non Es+ cells formed rosettes with dog erythrocytes. Among Es+Ed+ cells, T4 antigen-positive cells were observed approximately 1.7 times as often as T8 antigen-positive cells, when measured by staining with OKT4 or OKT8 monoclonal antibody. Among Es+Ed- cells, however, T4 and T8 antigen-positive cells were observed in almost equal proportion. Preincubation of PBM with OKT11 monoclonal antibody, but not with OKT4 monoclonal antibody, inhibited the rosette formation with dog as well as sheep erythrocytes. These results indicated that Es+Ed+ cells were a subpopulation of T-cells in which a majority of the cells were T4 antigen-positive, and that the binding sites of dog erythrocytes on human T-cells was closely linked with that of sheep erythrocytes.