Figure 2.
IgG1-2 chimera is inefficiently cleaved by IdeS. (A) Model of the F(ab′)2 region of antibody cAC10 modeled with MOE; light chain (gray), heavy chain (blue), interchain disulfide (orange), and lower hinge (magenta). The P1 position of IdeS is G236. Numbering of residues is according to EU numbering nomenclature. (B) Alignment of the lower hinge of IgG1 and the IgG1-2 chimera. Residues in cyan are IgG2 isotype residues introduced into the lower hinge of IgG2. (C) Cleavage efficiency of human IgG1 and IgG1-2 chimera. One mg/ml of IgG1 and IgG1-2 were incubated for 24 hours at 37°C with different IdeS amounts as indicated. Cleavage was analyzed by capillary electrophoresis. While IgG1 is efficiently cleaved into F(ab′)2 at an IdeS:IgG ratio of 1:500, IgG1-2 requires 50-fold higher IdeS concentrations for complete cleavage.