CD32B also termed FcγRIIB is an 40 kDa glycoprotein coded by the FCGR2B gene on chromosome 1q23.3. CD32B is a type I transmembrane receptor with low affinity for monomeric IgG. CD32B is the only known inhibitory Fc gamma receptor.  It is expressed on subsets of lymphocytes, dendritic cells, and endothelial cells. CD32B reduces downstream signaling of co-localized activating receptors following ligand-induced crosslinking. CD32B is known as a critical regulatory element in B-cell homeostasis as it controls cell activation by counterbalancing the stimulatory activity of multiple receptors, including the B-cell antigen receptor (BCR). It down-regulates B cell activation by increasing the threshold for BCR activation and suppresses B cell-mediated Ag presentation to T cells. CD32B is of considerable therapeutic interest. On normal and malignant B cells, CD32B can play a role in internalizing the anti-CD20 antibody drug rituximab from the B cell surface which results in an abrogation of its cell-mediated anticancer mechanisms. Moreover, CD32B is involved in adaptation to all kinds of intravenous Ig treatments, and it can potentiate the immunostimulatory activities of certain therapeutic mAbs targeting TNFR family members. Therapeutic antibodies directly targeting CD32B are also under development. Suggested reading: https://jlb.onlinelibrary.wiley.com/doi/full/10.1002/jlb.2mir0917-354r.