IVIg Products classified by potential immunogenicity of class II “clusters” HCP sequences. Characterization of host cell proteins (HCPs) by immunogenicity metrics. Each subplot represents one of the four products. Within each subplot, individual epitope clusters are plotted using the JanusMatrix Score on the x-axis and the EpiMatrix Score on the y-axis. Clusters are epitope-dense regions within a protein. Each point represents a single cluster identified from any HCP sequence found in the product. Proteins containing multiple clusters contribute multiple points. To obtain cluster scores, proteins were first parsed into overlapping 9-mer peptides, and each 9-mer was evaluated using the EpiMatrix algorithm for MHC class II-binding potential. Epitope-dense regions (clusters) were then identified using ClustiMer. These were then characterized using the JanusMatrix algorithm to determine similarity to the human proteome. Red clusters have higher immunogenic potential than green clusters, which are highly conserved within the human proteome.