TABLE 2.

Summary of primary positive hits identified from Fc libraries

The Fc libraries were screened by a high throughput competition AlphaLISA® assay to find Fc mutants with improved binding to FcγRIIIA (Phe-158), after the first round of primary screen; Fc mutants with >20% inhibition to the interaction of regular IgG1/FcγRIIIA (Phe-158) were scored as positive hits. Two more rounds of competition AlphaLISA® assay were conducted to confirm the activity. Left panel, positive hits from Tier 1 and Tier 3 Fc libraries. Right panel, positive hits from Tier 2 Fc libraries. Amino acid residues with superscript “a” indicate they were identified previously by Shields et al. (12). Amino acid residues with superscript “b” indicate they were identified previously by Lazar et al. (13). Amino acid residues with superscript “c” indicate they were identified previously by Stavenhagen et al. (14).