Atomic force microscopy to study the effects of ITIM-bearing FcγRIIB on the activation of RBL-2H3 cells

We have studied here the effects of ITIM-bearing FcγRIIB2 on the FcεRI-dependent activation of rat basophilic leukemia (RBL-2H3) cells by atomic force microscopy (AFM). AFM images showed that ruffling and degranulation of RBL-2H3 cells were significantly reduced but the cell spreading was not by the co-clustering of FcγRIIB2 and FcεRI. From the results it was shown that the co-clustering of ITIM-bearing negative co-receptors in a single RBL cell hardly induce the degranulation though the [Ca²⁺](i) increased transiently in the cell. This suggested that secretory responses and the membrane ruffling which were induced by the crosslinkng of FcγRII should be negatively controlled by the co-clustering of FcγRII. Copyright (C) 2000 Elsevier Science B.V.