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. Author manuscript; available in PMC: 2014 Jul 14.
Published in final edited form as: Sci Transl Med. 2013 Jul 17;5(194):194ra92. doi: 10.1126/scitranslmed.3005795

Fig. 1. AAV empty capsids prevent vector neutralization by anti-AAV NAbs in vivo in mice.

Fig. 1

(A) Anti-AAV8 antibody analysis in naïve mice injected intraperitoneally with PBS only or mice passively immunized intraperitoneally with 0.5, 5, 15, or 50 mg of IVIg (n = 5 per group). The analysis was performed 24 hours after immunization. “NAb titer” represents the reciprocal serum dilution at which <50% inhibition of the reporter vector signal was measured in the NAb assay. “% Inhibition undiluted serum” represents the inhibition of the reporter gene signal observed when undiluted test serum was mixed with an equal volume of a solution containing the reporter vector. #, range. (B) Male C57BL/6 mice (n = 5 per group) were injected intraperitoneally with 0.5 mg of IVIg (resulting in a NAb titer of 1:1 to 1:3) or injected with PBS (−). After 24 hours, animals received either 1 × 109 vg (gray bars) or 5 × 109 vg (black bars) of an AAV8-F.IX vector alone (0X) or formulated with a 10X excess of AAV8 empty capsids [1 × 1010 capsid particles (gray bars) or 5 × 1010 capsid particles (black bars)]. hF.IX transgene levels in plasma at week 8 after vector delivery are shown as averages; error bars, SEM. *P < 0.05 versus naïve mice (two-tailed, unpaired t test). (C) Vector gene copy number in mouse livers collected at week 12 after AAV8-F.IX gene transfer at a vector dose of 5 × 109 vg per animal. Results are shown as average copy number of five livers. Error bars, SEM. Experimental groups are the same as shown in (B). *P < 0.05 versus naïve mice (two-tailed, unpaired t test). (D) Empty capsids from alternate AAV serotypes protect AAV8-F.IX vector from NAb neutralization. Male C57BL/6 mice (n = 5 per group) were passively immunized with 0.5 mg of IVIg or injected with PBS (−) intraperitoneally. Twenty-four hours after, animals received 5 × 109 vg of an AAV8-F.IX vector alone (−) or formulated with a 10X excess of AAV8, AAV2, or AAV5 empty capsids. The percent residual expression is calculated relative to the F.IX transgene plasma levels in naïve animals receiving the AAV-F.IX vector only. *P < 0.05 versus naïve mice (two-tailed, unpaired t test).