Figure 1.

Despite the relatively low expression levels generated in primates, humoral immune tolerance to human α-galactosidase can be achieved after prolonged expression. Two juvenile male rhesus macaques (R-15, R-18) were injected intravenously with 2 × 10¹³ drp/kg AAV8-αgal; one juvenile male rhesus macaque (R-22) was a naive (non-transduced) control. (a) Serum α-galactosidase A (α-gal) and (b) anti-α-gal titers were determined over time. Day 0 levels represent background for each animal, i.e., before vector administration. All three monkeys were challenged with α-gal in complete Freund's adjuvant (CFA; arrows): R-22 at day 0, R-18 at day 84, and R-15 at day 112. Monkey R-15 was rechallenged with α-gal in incomplete Freund's adjuvant (IFA; arrows) at day 200. Three juvenile male cynomolgus macaques (C-1, C-2, C-3) were injected intravenously with 2 × 10¹³ drp/kg AAV8-αgal. (c) Serum α-gal and (d) anti-α-gal titers were determined over time. Day 0 levels represent background for each animal, i.e., before vector administration. One monkey (C-2) was challenged with α-gal in CFA at day 28, and the remaining two were challenged at day 84 (arrows).