Humoral immune response after mesenteric or peripheral vein administration of scAAV vector. (A) Plasma obtained from macaques after peripheral (M5-sc, ○; M6-sc, □; M7-sc, ▵) or mesenteric vein (M1-sc, broken line and •; M2-sc, broken line and ♦; see Nathwani et al¹ ) administration of scAAV2/8-LP1-hFIXco was analyzed for the presence of AAV8-specific IgG by ELISA (left-hand panel). AAV5-specific IgG titers after peripheral (M8-sc, □; M9-sc, ○) or mesenteric vein (328, broken line and ▾; M4-sc, broken line and ▪) administration of scAAV2/5-LP1-hFIXco are shown in the right-hand panel. (B) Specific isotype profiles of the humoral immune response after administration of scAAV2/8-LP1-hFIXco and scAAV2/5-LP1-hFIXco, respectively (IgM, □; IgG₁, ○; IgG₂, ▵; IgG₄, ⋄).