Structural and functional characterization of capsid binding by anti-AAV9 monoclonal antibodies from infants after SMA gene therapy

• Published in: Molecular therapy Vol. 31; no. 7; pp. 1979 - 1993
• Main Authors: Logan, Grant J., Mietzsch, Mario, Khandekar, Neeta, D’Silva, Arlene, Anderson, Daniel, Mandwie, Mawj, Hsi, Jane, Nelson, Austin R., Chipman, Paul, Jackson, Jennifer, Schofield, Peter, Christ, Daniel, Goodnow, Christopher C., Reed, Joanne H., Farrar, Michelle A., McKenna, Robert, Alexander, Ian E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 05.07.2023; American Society of Gene & Cell Therapy
• Subjects: adeno-associated virus vector; affinity; Animals; anti-vector immunity; Antibodies, Monoclonal - genetics; Antibodies, Monoclonal - therapeutic use; capsid; Capsid - chemistry; Capsid Proteins - chemistry; capsid structure; Cryoelectron Microscopy; Dependovirus; Genetic Therapy; Genetic Vectors - genetics; Humans; Infant; Mice; monoclonal antibody; neutralization; Original; recombinant AAV; spinal muscular atrophy; Zolgensma; capsid structure; neutralization; Zolgensma; capsid; recombinant AAV; spinal muscular atrophy; monoclonal antibody; anti-vector immunity; adeno-associated virus vector; affinity
• ISSN: 1525-0016; 1525-0024; 1525-0024
• DOI: 10.1016/j.ymthe.2023.03.032

Success in the treatment of infants with spinal muscular atrophy (SMA) underscores the potential of vectors based on adeno-associated virus (AAV). However, a major obstacle to the full realization of this potential is pre-existing natural and therapy-induced anti-capsid humoral immunity. Structure-guided capsid engineering is one possible approach to surmounting this challenge but necessitates an understanding of capsid-antibody interactions at high molecular resolution. Currently, only mouse-derived monoclonal antibodies (mAbs) are available to structurally map these interactions, which presupposes that mouse and human-derived antibodies are functionally equivalent. In this study, we have characterized the polyclonal antibody responses of infants following AAV9-mediated gene therapy for SMA and recovered 35 anti-capsid mAbs from the abundance of switched-memory B (smB) cells present in these infants. For 21 of these mAbs, seven from each of three infants, we have undertaken functional and structural analysis measuring neutralization, affinities, and binding patterns by cryoelectron microscopy (cryo-EM). Four distinct patterns were observed akin to those reported for mouse-derived mAbs, but with early evidence of differing binding pattern preference and underlying molecular interactions. This is the first human and largest series of anti-capsid mAbs to have been comprehensively characterized and will prove to be powerful tools for basic discovery and applied purposes. [Display omitted] Logan and colleagues show that Zolgensma-treated infants mount robust and sustained anti-vector antibody responses. They also isolate the single largest collection of human anti-AAV monoclonal antibodies and functionally and structurally characterize their capsid-binding properties to provide valuable insights into host-vector responses as well as a powerful toolkit for scientific applications.