Successful Liver transduction by Re-administration of Different Adeno-Associated Virus Vector Serotypes in Mice

Abstract

Intravenous administration of adeno-associated virus (AAV) vector is a promising gene therapy approach for monogenic diseases. However, re-administration of the same AAV serotype is impossible due to the induction of anti-AAV neutralizing antibodies (NAbs). Here we examined the feasibility of re-administration of AAV vectors to change the serotypes. We administered AAV3B, AAV5, or AAV8 vectors targeting the liver of C57BL/6 mice intravenously, and then assessed the emergence of NAbs and the transduction efficacy with a second administration. For all serotypes, we confirmed that re-administration with the same serotype was not possible. Although the highest neutralizing activity of NAb was induced by AAV5; however, the NAbs elicited by AAV5 did not react with any other serotypes, resulting in success in re-administration with the other serotypes. The re-administration of AAV5 was also successful in all mice treated with AAV3B and AAV8. The effective secondary administration of AAV3B and AAV8 was observed in most mice treated with AAV8 and AAV3B, respectively. However, few mice developed NAbs cross-reactive with the other serotypes, especially the serotypes with close sequence homology. In summary, AAV vector administration induced NAbs relatively specific to the serotype administrated. Secondary administration of AAVs targeting liver transduction could be successfully achieved by switching AAV serotypes in mice.

Viral vector‐based cancer treatment and current clinical applications

“…109 Thus, readministration of different AAV serotypes is one of the strategies to reduce the immunogenicity of AAV vectors. 110,111 However, the immune cross-activity of different AAV serotypes-to a certain extent-limits such application. 110 Modification of the capsid is another strategy for escaping the host immune response.…”

“…110,111 However, the immune cross-activity of different AAV serotypes-to a certain extent-limits such application. 110 Modification of the capsid is another strategy for escaping the host immune response. The structures of host NAbs complexed with viral capsids, illustrating the key amino acids for their bindings.…”

“…Re‐administration of the same AAV serotype further enhances neutralizing antibodies (NAbs) titer, leading to low efficiency of treatment 109 . Thus, re‐administration of different AAV serotypes is one of the strategies to reduce the immunogenicity of AAV vectors 110,111 . However, the immune cross‐activity of different AAV serotypes—to a certain extent—limits such application 110 …”

The seroprevalence of neutralizing antibodies against the adeno-associated virus capsids in Japanese hemophiliacs

“…We confirmed that our AAV vector contained >80% of full particles by analytical ultracentrifugation (data not shown). Finally, the titer of the AAV vector was determined, as described previously 42 .…”

“…On the contrary, ND 50 to neutralize >50% vector transduction at 1:3000 dilution considered as 1:3000. We employed 1:1 as the cutoff value for NAb-positive in this study because our previous data showed that a low dose of AAV8 vector (5 × 10 11 vg/kg) was inhibited in mice whose serum NAb titer was 1:1 42 . We consistently used human immunoglobulin (GAMMAGARD ® , Shire plc, Dublin, Ireland) as a positive control and confirmed that the variation of ND 50 in each measurement was within 3-fold.…”