Dystrophin Immunity in Duchenne's Muscular Dystrophy

The Joint Outcome Study Investigators 7Recombinant adeno-associated virus (rAAV) is a promising gene delivery vector and has recently been used in patients with hemophilia. One limitation of AAV application is that most humans have experienced wild-type AAV serotype 2 exposure, which frequently generates neutralizing antibodies (NAbs) that may inhibit rAAV2 vector transduction. Employing alternative serotypes of rAAV vectors may circumvent this problem. We investigated the development of NAbs in early childhood by examining sera gathered prospectively from 62 children with hemophilia A, participating in a multi-institutional hemophilia clinical trial (the Joint Outcome Study). Clinical applications in hemophilia therapy have been suggested for serotypes AAV2, AAV5 and AAV8, therefore NAbs against these serotypes were serially assayed over a median follow-up of 4 years. NAbs prevalence increased during early childhood for all serotypes. NAbs against AAV2 (43.5%) were observed more frequently and at higher titers compared with both AAV5 (25.8%) and AAV8 (22.6%). NAbs against AAV5 or AAV8 were rarely observed in the absence of co-prevalent and higher titer AAV2 NAbs, suggesting that NAbs to AAV5 and AAV8 were detected following AAV2 exposure due to partial cross-reactivity of AAV2-directed NAbs. The results may guide rational design of clinical trials using alternative AAV serotypes and suggest that younger patients who are given AAV gene therapy will benefit from the lower prevalence of NAbs.

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“…37,38 One such mutant designed in our lab has been used in patients with Duchenne muscular dystrophy in a Phase I human clinical trial. 39 …”

Section: Discussionmentioning

confidence: 99%

Neutralizing antibodies against adeno-associated virus examined prospectively in pediatric patients with hemophilia

Li¹,

Narkbunnam

Samulski³

et al. 2011

Gene Ther

195

191

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“…The majority of the human population has a natural AAV2 infection, and about half of these individuals have NAbs in the blood, which can prevent AAV transduction after systemic application. A number of surveys have demonstrated that NAb cross-activity exists among types of AAV (6,10,27,45). Most recent studies, including our own, have been focused on how to evade NAb activity, and our efforts have included modification of the AAV virion or blocking NAb activity with immunosuppressants.…”

Section: Discussionmentioning

confidence: 99%

“…Although 11 additional types of AAV have been isolated for gene therapy purposes, little to no cross-reactivity of NAbs is demonstrated among these types in animals (27,30,38,60,65). In humans, recent studies have shown that different degrees of NAb cross-reactivity exist between AAV2 and other types (6,10,27,45). There is a lower prevalence of NAbs against AAV1,10).…”

mentioning

confidence: 99%

Single Amino Acid Modification of Adeno-Associated Virus Capsid Changes Transduction and Humoral Immune Profiles

DiPrimio

Bowles

et al. 2012

J Virol

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Adeno-associated virus (AAV) vectors have the potential to promote long-term gene expression. Unfortunately, humoral immunity restricts patient treatment and in addition provides an obstacle to the potential option of vector readministration. In this study, we describe a comprehensive characterization of the neutralizing antibody (NAb) response to AAV type 1 (AAV1) through AAV5 both in vitro and in vivo. These results demonstrated that NAbs generated from one AAV type are unable to neutralize the transduction of other types. We extended this observation by demonstrating that a rationally engineered, muscle-tropic AAV2 mutant containing 5 amino acid substitutions from AAV1 displayed a NAb profile different from those of parental AAV2 and AAV1. Here we found that a single insertion of Thr from AAV1 into AAV2 capsid at residue 265 preserved high muscle transduction, while also changing the immune profile. To better understand the role of Thr insertion at position 265, we replaced all 20 amino acids and evaluated both muscle transduction and the NAb response. Of these variants, 8 mutants induced higher muscle transduction than AAV2. Additionally, three classes of capsid NAb immune profile were defined based on the ability to inhibit transduction from AAV2 or mutants. While no relationship was found between transduction, amino acid properties, and NAb titer or its cross-reactivity, these studies map a critical capsid motif involved in all steps of AAV infectivity. Our results suggest that AAV types can be utilized not only as templates to generate mutants with enhanced transduction efficiency but also as substrates for repeat administration.A deno-associated virus (AAV) vectors have been safely and successfully used in phase I clinical trials (39,40,54). In particular, therapeutic effects have been achieved in patients with Leber's congenital amaurosis and hemophilia B. Among 30 patients with Leber's congenital amaurosis, 28 demonstrated remarkably improved eyesight after AAV type 2 (AAV2) delivery of the rpe65 gene to the retina. Regarding the recent hemophilia B trial, all six patients had therapeutic factor IX (FIX) expression within a beneficial 1% to 8% of normal levels as long as 18 months after intravenous delivery of an AAV vector encoding an optimized FIX cassette (54).AAV is a nonenveloped, single-stranded DNA virus that requires a helper virus, such as adenovirus (Ad) or herpes simplex virus, for efficient replication. Despite the lack of inflammation or other AAV-associated complications following administration of AAV2 vectors in several organs, neutralizing antibody (NAb) titers against the AAV2 capsid were found to be significantly increased following vector administration, particularly in the lung, muscle, and liver (7, 8, 43-45, 49, 54, 63). NAbs in circulation are able to block AAV transduction after systemic administration. Recently, Manno et al. (44) performed a phase I study of AAV-mediated FIX transgene delivery in patients with hemophilia B, in which one patient with a higher preexisting NAb ti...

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“…Next, we set up an Enzyme-linked immunosorbent spot (ELISPOT) assay to determine whether mdx mice possess specific antidystrophin reacting T-lymphocytes, similarly to those individuated in patients. 20,21 Reactive lymphocytes against the epitopes of dystrophin corresponding to the exons upstream the dystrophin mutation were found in DMD patients. 20 The mutation of the dystrophin gene of the mdx is a stop codon in exon 23.…”

Section: T-lymphocytes Priming In Dystrophic Micementioning

confidence: 99%

Therapeutic Potential of Immunoproteasome Inhibition in Duchenne Muscular Dystrophy

et al. 2016

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Duchenne muscular dystrophy is an inherited fatal genetic disease characterized by mutations in dystrophin gene, causing membrane fragility leading to myofiber necrosis and inflammatory cell recruitment in dystrophic muscles. The resulting environment enriched in proinflammatory cytokines, like IFN-γ and TNF-α, determines the transformation of myofiber constitutive proteasome into the immunoproteasome, a multisubunit complex involved in the activation of cell-mediate immunity. This event has a fundamental role in producing peptides for antigen presentation by MHC class I, for the immune response and also for cytokine production and T-cell differentiation. Here, we characterized for the first time the presence of T-lymphocytes activated against revertant dystrophin epitopes, in the animal model of Duchenne muscular dystrophy, the mdx mice. Moreover, we specifically blocked i-proteasome subunit LMP7, which was up-regulated in dystrophic skeletal muscles, and we demonstrated the rescue of the dystrophin expression and the amelioration of the dystrophic phenotype. The i-proteasome blocking lowered myofiber MHC class I expression and self-antigen presentation to T cells, thus reducing the specific antidystrophin T cell response, the muscular cell infiltrate, and proinflammatory cytokine production, together with muscle force recovery. We suggest that i-proteasome inhibition should be considered as new promising therapeutic approach for Duchenne muscular dystrophy pathology.

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Dystrophin Immunity in Duchenne's Muscular Dystrophy

Cited by 562 publications

References 23 publications

Neutralizing antibodies against adeno-associated virus examined prospectively in pediatric patients with hemophilia

Neutralizing antibodies against adeno-associated virus examined prospectively in pediatric patients with hemophilia

Single Amino Acid Modification of Adeno-Associated Virus Capsid Changes Transduction and Humoral Immune Profiles

Therapeutic Potential of Immunoproteasome Inhibition in Duchenne Muscular Dystrophy

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