Cariappa, AnnaiahTakematsu, HiromuLiu, HaoyuanDiaz, SandraHaider, KhaledaKalloo, GeetikaVarki, NissiVarki, AjitBoboila, CristianConnole, MichelleShi, HaiPillai, Shiv2011-04-182009Cariappa, Annaiah, Hiromu Takematsu, Haoyuan Liu, Sandra Diaz, Khaleda Haider, Cristian Boboila, Geetika Kalloo, et al. 2009. B cell antigen receptor signal strength and peripheral B cell development are regulated by a 9-O-acetyl sialic acid esterase. Journal of Experimental Medicine 206(1): 125-138.0022-1007http://nrs.harvard.edu/urn-3:HUL.InstRepos:4853404We show that the enzymatic acetylation and deacetylation of a cell surface carbohydrate controls B cell development, signaling, and immunological tolerance. Mice with a mutation in sialate:O-acetyl esterase, an enzyme that specifically removes acetyl moieties from the 9-OH position of α2–6-linked sialic acid, exhibit enhanced B cell receptor (BCR) activation, defects in peripheral B cell development, and spontaneously develop antichromatin autoantibodies and glomerular immune complex deposits. The 9-O-acetylation state of sialic acid regulates the function of CD22, a Siglec that functions in vivo as an inhibitor of BCR signaling. These results describe a novel catalytic regulator of B cell signaling and underscore the crucial role of inhibitory signaling in the maintenance of immunological tolerance in the B lineage.en-USJournal Article2011-04-1810.1084/jem.20081399