Influence of Pre-existing Anti-capsid Neutralizing and Binding Antibodies on AAV Vector Transduction

Figures

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  Figure 1. Influence of Anti-AAV8 Neutralizing Antibodies on Transgene Expression and Vector Persistence in Blood and Liver (A) Experimental design; red symbols represent timing of blood collection. Sac., sacrifice. (B) FIX transgene plasma levels at 3 hr and 1, 3, 7, and 14 days post-gene transfer (n = 5) are shown. (C and D) Vector persistence in plasma (C) and liver (D) of animals starting at 3 hr post-vector infusion (n = 5/time point) is shown. Statistical significance over the PBS control group was determined using the Mann-Whitney test. **p < 0.01; ***p < 0.001; ****p < 0.0001; n.s., not significant. Data are represented as mean ± SEM.

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  Figure 2. AAV Vector Uptake by Both Liver Parenchymal and Non-parenchymal Cells (A) Experimental design; red symbols represent timing of blood collection. (B) Vector persistence in plasma 3 hr post-vector delivery is shown. (C) Vector genomes determined in liver parenchymal (PC) and non-parenchymal (NPC) cells 3 hr post-AAV8-FIX delivery are shown. The statistical significance over the PBS group was determined by the Mann-Whitney test. **p < 0.01; ***p < 0.001; vg, vector genomes. Data are represented as mean ± SEM.

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  Figure 3. Internalization of AAV2 Immune Complexes in a Murine Hepatocyte Cell Line (A) Luciferase transgene expression levels in the presence of different IVIg concentrations. Results are reported as % of maximum signal (0 mg/mL IVIg). (B and C) Frequency of cells positive for AAV2 (B) and human IgG (C) is shown. (D) Detection of the fluorescent spots representing the hIgG and AAV2 capsid internalized in hepatocytes is shown. Representative cell images of hIgG and AAV2 capsid presence in hepatocytes are shown for each IVIg concentration and the corresponding NAb titer. The percentage of the fluorescent spots representing AAV2 capsid that have an average area >2 (a.u.) is reported. Each experiment shown here was repeated and analyzed at least twice. IVIg, intravenous immunoglobulins. NAb, neutralizing antibody.

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  Figure 4. Effect of Neutralizing and Non-neutralizing Antibodies on the Entry of AAV8 Vector Particles in Hepa 1-6 and HEK293 Cells (A) Representative images of cells analyzed by imaging flow cytometry. The blue arrows show the presence of AAV8 particles and the red arrows the colocalization of AAV8 particles with human IgG staining. (B) Frequency of cells positive for AAV8 capsid is shown. (C) Frequency of cells positive for human IgG is shown. (D) Luciferase transgene expression (% of RLU) is shown. Statistical significance of BAb over the NAb, C, and PBS group was determined using Student’s t test. *p < 0.05; **p < 0.01; ***p < 0.001. (E) Fc block experiment is shown. Serum samples diluted 1:36.1 were pre-incubated with increasing concentrations of an anti-hIgG antibody, Fc fragment specific, before adding to the mix an AAV8-luciferase vector. Residual luciferase transgene expression after transduction of HEK293 cells at an MOI of 200 is shown. Data derived from experiments were performed in duplicate. Data are represented as mean ± SEM. BAb, binding antibodies; BF, bright field; C, children naive to AAV8; RLU, relative light units.

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  Figure 5. Liver Transduction Profile in Mice Passively Immunized with Pre-existing Neutralizing or Non-neutralizing Antibodies (A) Experimental design; red symbols represent timing of blood collection. (B) Treatment cohorts are shown. (C) FIX transgene expression levels assessed by ELISA are shown to be eliminated. Results are shown as % of PBS treated. (D) Vector genome copy number per diploid genome in the liver of animals by qPCR at the time of sacrifice is shown. Statistical significance of BAb over the NAb, C, and PBS group was determined using Student’s t test. *p < 0.05; **p < 0.01; ***p < 0.001. Data are represented as mean ± SEM.

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  Figure 6. Biodistribution of AAV8 Vector after Systemic Delivery in Mice Passively Immunized with Neutralizing or Non-neutralizing Antibodies Vector genome copy number in various tissues was determined. (A) Lungs are shown. (B) Skeletal muscle is shown. (C) Spleen is shown. (D) Inguinal lymph nodes are shown. Statistical significance of BAb over the NAb, C, and PBS group was determined using Student’s t test. *p < 0.05; ***p < 0.0001. TA, tibialis anterior. Data are represented as mean ± SEM.

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  Figure 7. Persistence of AAV8 Vector in the Bloodstream of Mice Harboring Pre-existing Neutralizing or Non-neutralizing Antibodies and Evaluation of the Anti-AAV8 Capsid Humoral Immune Response (A) Clearance of vector genomes from plasma over time. (B) Total anti-AAV8 capsid murine IgG (mIgG) at the time of sacrifice is shown. (C) Anti-AAV8 neutralizing antibodies at the time of sacrifice are shown. Statistical significance of BAb over the NAb, C, and PBS group was determined using Student’s t test. *p < 0.05; **p < 0.01; ***p < 0.001. Data are represented as mean ± SEM.