TNF-alpha induces spreading of B-CLL via the CD11c/CD18 molecule

Activation of malignant B cells can lead to extensive morphological changes of these cells. A combination of PMA and TNF-α can induce adherence of purified B-CLL cells, which acquire a dendritic cell-like appearance. This phenomenon that we have termed spreading, is accompanied by upregulation of expression of both β1 and β2 integrin molecules. Spreading was inhibited by the addition of antibodies against CD18 or CD11c. In other B cell malignancies (HCL and NHL), morphological changes could be induced by PMA in the absence of TNF-α. Culturing in the presence of prednisolone resulted in an inhibition of spreading, most likely mediated via a down regulation of CD18 and CD11c expression. These data indicate that the CD11c/CD18 complex might be important for the adhesive properties of B cells. © 1993 Wiley-Liss, Inc.