Clinical Laboratory and Center for Clinical Studies, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
PLoS One. 2019 Mar 21;14(3):e0212811. doi: 10.1371/journal.pone.0212811. eCollection 2019.
Adeno-associated virus (AAV) vectors represent promising candidates for gene therapy; however, pre-existing neutralizing antibodies (NAb) may reduce AAV vector delivery efficiency. In this study, the presence of AAV NAb was investigated in cats, which serve as a larger and outbred animal model for the prediction of gene therapy outcomes in humans but also in cats.Serum/plasma samples from 230 client-owned Swiss cats and 20 specified pathogen-free cats were investigated for NAb to AAV1, AAV2, AAV5, AAV6, AAV7, AAV8 and AAV9 using in vitro transduction inhibition and a beta-galactosidase assay. NAb to all tested AAV serotypes were found. Of the client-owned cats, 53% had NAb to one or more of the AAV serotypes. NAb (≥1:10) were found at frequencies of 5% (AAV6) to 28% (AAV7). The highest titers were found against AAV7 (≥1:160). The NAb prevalence to AAV2, AAV7 and AAV9 differed geographically. Regarding titers ≥1:10 against single AAV serotypes, age, breed and sex of the cats were not associated with the NAb prevalence. Cats with titers ≥1:20 against AAV2 and titers ≥1:40 against AAV7 were significantly younger than cats with low/no titers, and purebred cats were significantly more likely than non-purebred cats to have NAb to AAV2 (≥1:40). Additionally, regarding NAb to all AAV combined, female cats were significantly more likely than male cats to have NAb titers ≥1:40. Preliminary data using AAV-DJ indicated that less pre-existing NAb to the hybrid AAV-DJ can be expected compared to the wild-type AAV serotypes. AAV NAb will need to be taken into account for future in vivo gene therapy studies in cats.
腺相关病毒 (AAV) 载体是基因治疗的有前途的候选者；然而，预先存在的中和抗体 (NAb) 可能会降低 AAV 载体的递送效率。在这项研究中，研究了猫体内 AAV NAb 的存在情况，猫作为一种更大的、远交的动物模型，可以预测人类基因治疗的结果，但也存在于猫体内。使用体外转导抑制和β-半乳糖苷酶测定法，检测了 230 只客户拥有的瑞士猫和 20 只特定病原体无猫的血清/血浆样本中对 AAV1、AAV2、AAV5、AAV6、AAV7、AAV8 和 AAV9 的 NAb。发现了针对所有测试 AAV 血清型的 NAb。在客户拥有的猫中，53%的猫对一种或多种 AAV 血清型具有 NAb。发现 NAb（≥1:10）的频率为 5%（AAV6）至 28%（AAV7）。针对 AAV7 的滴度最高（≥1:160）。AAV2、AAV7 和 AAV9 的 NAb 流行率在地理上有所不同。关于针对单个 AAV 血清型的 titers≥1:10，猫的年龄、品种和性别与 NAb 流行率无关。针对 AAV2 的 titers≥1:20 和针对 AAV7 的 titers≥1:40 的猫比低/无 titers 的猫明显年轻，纯种猫比非纯种猫更有可能对 AAV2（≥1:40）具有 NAb。此外，关于针对所有 AAV 的 NAb，与雄性猫相比，雌性猫更有可能具有 titers≥1:40 的 NAb。使用 AAV-DJ 的初步数据表明，与野生型 AAV 血清型相比，预计对杂交 AAV-DJ 的预先存在的 NAb 会更少。在未来的猫体内基因治疗研究中，需要考虑 AAV NAb。
