@article {1580500,
	title = {Engineering adeno-associated viral vectors to evade innate immune and inflammatory responses},
	journal = {Sci Transl Med},
	volume = {13},
	number = {580},
	year = {2021},
	month = {2021 Feb 10},
	abstract = {Nucleic acids are used in many therapeutic modalities, including gene therapy, but their ability to trigger host immune responses in vivo can lead to decreased safety and efficacy. In the case of adeno-associated viral (AAV) vectors, studies have shown that the genome of the vector activates Toll-like receptor 9 (TLR9), a pattern recognition receptor that senses foreign DNA. Here, we engineered AAV vectors to be intrinsically less immunogenic by incorporating short DNA oligonucleotides that antagonize TLR9 activation directly into the vector genome. The engineered vectors elicited markedly reduced innate immune and T cell responses and enhanced gene expression in clinically relevant mouse and pig models across different tissues, including liver, muscle, and retina. Subretinal administration of higher-dose AAV in pigs resulted in photoreceptor pathology with microglia and T cell infiltration. These adverse findings were avoided in the contralateral eyes of the same animals that were injected with the engineered vectors. However, intravitreal injection of higher-dose AAV in macaques, a more immunogenic route of administration, showed that the engineered vector delayed but did not prevent clinical uveitis, suggesting that other immune factors in addition to TLR9 may contribute to intraocular inflammation in this model. Our results demonstrate that linking specific immunomodulatory noncoding sequences to much longer therapeutic nucleic acids can "cloak" the vector from inducing unwanted immune responses in multiple, but not all, models. This "coupled immunomodulation" strategy may widen the therapeutic window for AAV therapies as well as other DNA-based gene transfer methods.},
	issn = {1946-6242},
	doi = {10.1126/scitranslmed.abd3438},
	author = {Chan, Ying Kai and Wang, Sean K and Chu, Colin J and Copland, David A and Letizia, Alexander J and Costa Verdera, Helena and Chiang, Jessica J and Sethi, Meher and Wang, May K and Neidermyer, William J and Chan, Yingleong and Lim, Elaine T and Graveline, Amanda R and Sanchez, Melinda and Boyd, Ryan F and Vihtelic, Thomas S and Inciong, Rolando Gian Carlo O and Slain, Jared M and Alphonse, Priscilla J and Xue, Yunlu and Robinson-McCarthy, Lindsey R and Tam, Jenny M and Jabbar, Maha H and Sahu, Bhubanananda and Adeniran, Janelle F and Muhuri, Manish and Tai, Phillip W L and Xie, Jun and Krause, Tyler B and Vernet, Andyna and Pezone, Matthew and Xiao, Ru and Liu, Tina and Wang, Wei and Kaplan, Henry J and Gao, Guangping and Dick, Andrew D and Mingozzi, Federico and McCall, Maureen A and Cepko, Constance L and Church, George M}
}
