High-resolution physicochemical characterization of different intravenous immunoglobulin products
(A) Deconvoluted mass spectrum of papain cleaved Fc from Oct-1 (expired 5 months prior to analysis). Highlighted glycoforms labeled with “Hex,” “2Hex,” or “3Hex” indicate modified glycoforms with additional hexose units. (B) Relative quantitation of immunoglobulin G1 Fc glycoforms analysis of papain cleaved Fc from three lots of Octagam showing product age–related glycation; Oct-1 (5 months prior to expiration), Oct-2 (12 months after expiration), and Oct-3 (24 months after expiration). (C) Peptide liquid chromatography–mass spectrometry/mass spectrometry relative quantitation of nonenzymatic glycation of the peptide VSNK*ALPAPIEK from the CH2 domain of immunoglobulin G1. Data in panel C are displayed as mean ± standard deviation (n = 3 technical replicates). *Denotes glycated species. Gam, Gammagard lot; Oct, Octagam lot; Pri, Privigen lot.