2xa8

Publication Abstract from PubMed

Omalizumab, an anti-IgE antibody, used to treat severe allergic asthma and chronic idiopathic urticaria, binds to IgE in blood or membrane-bound on B lymphocytes but not to IgE bound to its high (FcepsilonRI) or low (CD23) affinity receptor. Mutagenesis studies indicate overlapping FcepsilonRI and omalizumab-binding sites in the Cepsilon3 domain, but crystallographic studies show FcepsilonRI and CD23-binding sites that are far apart, so how can omalizumab block IgE from binding both receptors? We report a 2.42-A omalizumab-Fab structure, a docked IgE-Fc/omalizumab-Fab structure consistent with available experimental data, and the free energy contributions of IgE residues to binding omalizumab, CD23, and FcepsilonRI. These results provide a structural and physical basis as to why omalizumab cannot bind receptor-bound IgE and why omalizumab-bound IgE cannot bind to CD23/FcepsilonRI. They reveal the key IgE residues and their roles in binding omalizumab, CD23, and FcepsilonRI.

Structural and Physical Basis for Anti-IgE Therapy.,Wright JD, Chu HM, Huang CH, Ma C, Chang TW, Lim C Sci Rep. 2015 Jun 26;5:11581. doi: 10.1038/srep11581. PMID:26113483^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.