Fig. 4.

The early BCR intrinsic events in B cell activation are a novel target for FcγRIIB inhibition. When co-engaged with the FcγRIIB (bottom) through binding of immune complexes (grey colored IgG and orange colored antigen) the FcγRIIB (bright blue color) blocks the BCR’s ability to form stable oligomers (Liu et al., 2009) and associate with raft lipids (Sohn et al., 2008a). Blocking these early events does not require molecular proximity of the cytoplasmic domains of the BCR and FcγRIIB but relies on the rapid and sustained association of the FcγRIIB with raft lipids.