Fig. 6.
Sheep erythrocyte rosette formation.
Highly purified BM MCs and HMC-1 cells (CD2+ and CD2− subsets) were incubated with sheep erythrocytes as described in the text. In the patient with SM, MCs were found to form rosettes with sheep erythrocytes (A), whereas no rosette formation was seen in a patient with reactive marrow (B). (C) A typical rosette of sheep erythrocytes on a CD2+ HMC-1 cell. In fact, in the CD2+ HMC-1 cell fraction, many sheep erythrocyte rosettes were found, whereas only few, if any, rosettes were found in the CD2− HMC-1 cell fraction (D). (E) A cluster of HMC-1 cells binding to sheep erythrocytes. In the same experiment, cluster and rosette formation were both inhibited by preincubating HMC-1 cells with the mAb 39C1.5 recognizing the T11-1 epitope of CD2 (F).