Schematics of C2-2b-2b and its constituent DNL modules. Structures and expression cassettes of CH3-AD2-IgG-hL243 (A) and IFNα2b-DDD2 (B), and C2-2b-2b (C). Blue and red helices represent DDD2 and AD2, respectively; SH indicates sulfhydryl groups of engineered cyseines; hL243 V, variable (green); C, constant (gray); G, hinge; L, linker; and hL, 6-His-linker.