High-resolution physicochemical characterization of different intravenous immunoglobulin products
Allotype distribution for the G1m1/nG1m1 isoallotypes by size-exclusion chromatography–time of flight–mass spectrometry (A) and heatmap of positive probes bound by intravenous immunoglobulin (IVIg) products on HuProt™ human proteome arrays (B). A total of 355 proteins on the HuProt™ arrays showed positive binding signals to the nine IVIg samples. These positive probes were clustered in the heatmap according to their A scores reflecting the signal intensities. Red color shows that a given sample has a higher-than-average A score for the given probe, and blue color reflects a lower-than-average A score. Each IVIg sample was probed on 2 arrays labeled as “–#a” and “–#b,” respectively. Single lots of each product were analyzed prior to or after the expiration date: Pri-1 (22 months after), Pri-2 (2 months prior), and Pri-3 (28 months after); Oct-1 (5 months prior), Oct-2 (12 months after), and Oct-3 (24 months after); Gam-1 (6 months after), Gam-2 (36 months prior), and Gam-3 (24 months after). Gam, Gammagard lot; Oct, Octagam lot; Pri, Privigen lot.