scholarly journals Examining the cross-reactivity and neutralization mechanisms of a panel of mAbs against adeno-associated virus serotypes 1 and 5

2012 ◽  
Vol 93 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Carole E. Harbison ◽  
Wendy S. Weichert ◽  
Brittney L. Gurda ◽  
John A. Chiorini ◽  
Mavis Agbandje-McKenna ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Gene Delivery ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Viral Infections ◽  
Cross Reactivity ◽  
Adeno Associated Virus ◽  
Viral Capsids ◽  
Serotype 1 ◽  
Antigenic Epitopes

Neutralizing antibodies play a central role in the prevention and clearance of viral infections, but can be detrimental to the use of viral capsids for gene delivery. Antibodies present a major hurdle for ongoing clinical trials using adeno-associated viruses (AAVs); however, relatively little is known about the antigenic epitopes of most AAV serotypes or the mechanism(s) of antibody-mediated neutralization. We developed panels of AAV mAbs by repeatedly immunizing mice with AAV serotype 1 (AAV1) capsids, or by sequentially immunizing with AAV1 followed by AAV5 capsids, in order to examine the efficiency and mechanisms of antibody-mediated neutralization. The antibodies were not cross-reactive between heterologous AAV serotypes except for a low level of recognition of AAV1 capsids by the AAV5 antibodies, probably due to the initial immunization with AAV1. The neutralization efficiency of different IgGs varied and Fab fragments derived from these antibodies were generally poorly neutralizing. The antibodies appeared to display various alternative mechanisms of neutralization, which included inhibition of receptor-binding and interference with a post-attachment step.

scholarly journals Adeno-Associated Virus Serotype 1 (AAV1)- and AAV5-Antibody Complex Structures Reveal Evolutionary Commonalities in Parvovirus Antigenic Reactivity

2014 ◽  
Vol 89 (3) ◽  
pp. 1794-1808 ◽  
Author(s):  
Yu-Shan Tseng ◽  
Brittney L. Gurda ◽  
Paul Chipman ◽  
Robert McKenna ◽  
Sandra Afione ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Clinical Trials ◽  
Image Reconstruction ◽  
Gene Delivery ◽  
Delivery System ◽  
Fold Axis ◽  
Adeno Associated Virus ◽  
Cryo Electron Microscopy ◽  
Antigenic Sites ◽  
Serotype 1

ABSTRACTThe clinical utility of the adeno-associated virus (AAV) gene delivery system has been validated by the regulatory approval of an AAV serotype 1 (AAV1) vector for the treatment of lipoprotein lipase deficiency. However, neutralization from preexisting antibodies is detrimental to AAV transduction efficiency. Hence, mapping of AAV antigenic sites and engineering of neutralization-escaping vectors are important for improving clinical efficacy. We report the structures of four AAV-monoclonal antibody fragment complexes, AAV1-ADK1a, AAV1-ADK1b, AAV5-ADK5a, and AAV5-ADK5b, determined by cryo-electron microscopy and image reconstruction to a resolution of ∼11 to 12 Å. Pseudoatomic modeling mapped the ADK1a epitope to the protrusions surrounding the icosahedral 3-fold axis and the ADK1b and ADK5a epitopes, which overlap, to the wall between depressions at the 2- and 5-fold axes (2/5-fold wall), and the ADK5b epitope spans both the 5-fold axis-facing wall of the 3-fold protrusion and portions of the 2/5-fold wall of the capsid. Combined with the six antigenic sites previously elucidated for different AAV serotypes through structural approaches, including AAV1 and AAV5, this study identified two common AAV epitopes: one on the 3-fold protrusions and one on the 2/5-fold wall. These epitopes coincide with regions with the highest sequence and structure diversity between AAV serotypes and correspond to regions determining receptor recognition and transduction phenotypes. Significantly, these locations overlap the two dominant epitopes reported for autonomous parvoviruses. Thus, rather than the amino acid sequence alone, the antigenic sites of parvoviruses appear to be dictated by structural features evolved to enable specific infectious functions.IMPORTANCEThe adeno-associated viruses (AAVs) are promising vectors forin vivotherapeutic gene delivery, with more than 20 years of intense research now realized in a number of successful human clinical trials that report therapeutic efficacy. However, a large percentage of the population has preexisting AAV capsid antibodies and therefore must be excluded from clinical trials or vector readministration. This report represents our continuing efforts to understand the antigenic structure of the AAVs, specifically, to obtain a picture of “polyclonal” reactivity as is the situation in humans. It describes the structures of four AAV-antibody complexes determined by cryo-electron microscopy and image reconstruction, increasing the number of mapped epitopes to four and three, respectively, for AAV1 and AAV5, two vectors currently in clinical trials. The results presented provide information essential for generating antigenic escape vectors to overcome a critical challenge remaining in the optimization of this highly promising vector delivery system.

scholarly journals Broad cross-reactivity across sarbecoviruses exhibited by a subset of COVID-19 donor-derived neutralizing antibodies

2021 ◽  
Author(s):  
Claudia A. Jette ◽  
Alexander A. Cohen ◽  
Priyanthi N.P. Gnanapragasam ◽  
Frauke Muecksch ◽  
Yu E. Lee ◽  
...  
Keyword(s):  
Binding Site ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Cross Reactivity ◽  
Antibody Therapeutics ◽  
Binding Domains ◽  
Cryptic Epitope ◽  
Binding Antibody ◽  
Β Sheet ◽  
Potent Neutralization

SummaryMany anti-SARS-CoV-2 neutralizing antibodies target the ACE2-binding site on viral spike receptor-binding domains (RBDs). The most potent antibodies recognize exposed variable epitopes, often rendering them ineffective against other sarbecoviruses and SARS-CoV-2 variants. Class 4 anti-RBD antibodies against a less-exposed, but more-conserved, cryptic epitope could recognize newly-emergent zoonotic sarbecoviruses and variants, but usually show only weak neutralization potencies. We characterized two class 4 anti-RBD antibodies derived from COVID-19 donors that exhibited broad recognition and potent neutralization of zoonotic coronavirus and SARS-CoV-2 variants. C118-RBD and C022-RBD structures revealed CDRH3 mainchain H-bond interactions that extended an RBD β-sheet, thus reducing sensitivity to RBD sidechain changes, and epitopes that extended from the cryptic epitope to occlude ACE2 binding. A C118-spike trimer structure revealed rotated RBDs to allow cryptic epitope access and the potential for intra-spike crosslinking to increase avidity. These studies facilitate vaccine design and illustrate potential advantages of class 4 RBD-binding antibody therapeutics.

Structurally Mapping Antigenic Epitopes of Adeno-Associated Virus 9: Development of Antibody Escape Variants

2021 ◽  
Author(s):  
Shanan N. Emmanuel ◽  
J. Kennon Smith ◽  
Jane Hsi ◽  
Yu-Shan Tseng ◽  
Matias Kaplan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Gene Delivery ◽  
General Population ◽  
Neutralizing Antibodies ◽  
Rational Design ◽  
Transduction Efficiency ◽  
Viral Neutralization ◽  
Patient Cohort ◽  
Antigenic Epitopes

Adeno-associated viruses (AAV) serve as vectors for therapeutic gene delivery. AAV9 vectors have been FDA approved, as Zolgensma®, for the treatment of spinal muscular atrophy and is being evaluated in clinical trials for the treatment of neurotropic and musculotropic diseases. A major hurdle for AAV-mediated gene delivery is the presence of pre-existing neutralizing antibodies in 40 to 80% of the general population. These pre-existing antibodies can reduce therapeutic efficacy through viral neutralization, and the size of the patient cohort eligible for treatment. In this study, cryo-electron microscopy and image reconstruction was used to define the epitopes of five anti-AAV9 monoclonal antibodies (MAbs); ADK9, HL2368, HL2370, HL2372, and HL2374, on the capsid surface. Three of these, ADK9, HL2370, and HL2374, bound on or near the icosahedral 3-fold axes, HL2368 to the 2/5-fold wall, and HL2372 to the region surrounding the 5-fold axes. Pseudo-atomic modeling enabled the mapping and identification of antibody contact amino acids on the capsid, including S454 and P659. These epitopes overlap with previously defined parvovirus antigenic sites. Capsid amino acids critical for the interactions were confirmed by mutagenesis followed by biochemical assays testing recombinant AAV9 (rAAV9) variants capable of escaping recognition and neutralization by the parental MAbs. These variants retained parental tropism and had similar or improved transduction efficiency compared to AAV9. These engineered rAAV9 variants could expand the patient cohort eligible for AAV9-mediated gene delivery by avoiding pre-existing circulating neutralizing antibodies. IMPORTANCE The use of recombinant AAVs (rAAVs) as delivery vectors for therapeutic genes is becoming increasingly popular, especially following the FDA approval of Luxturna® and Zolgensma®, based on serotypes AAV2 and AAV9, respectively. However, high titer anti-AAV neutralizing antibodies in the general population, exempts patients from treatment. The goal of this study is to circumvent this issue by creating AAV variant vectors not recognized by pre-existing neutralizing antibodies. The mapping of the antigenic epitopes of five different monoclonal antibodies (MAbs) on AAV9, to recapitulate a polyclonal response, enabled the rational design of escape variants with minimal disruption to cell tropism and gene expression. This study, which included four newly developed and now commercially available MAbs, provides a platform for the engineering of rAAV9 vectors that can be used to deliver genes to patients with pre-exiting AAV antibodies.

scholarly journals Persistence and decay of human antibody responses to the receptor binding domain of SARS-CoV-2 spike protein in COVID-19 patients

2020 ◽  
Vol 5 (52) ◽  
pp. eabe0367 ◽  
Author(s):  
Anita S. Iyer ◽  
Forrest K. Jones ◽  
Ariana Nodoushani ◽  
Meagan Kelly ◽  
Margaret Becker ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Symptom Onset ◽  
Neutralizing Antibodies ◽  
Serum Antibody ◽  
Cross Reactivity ◽  
Binding Domain ◽  
Antibody Responses ◽  
Human Antibody ◽  
Receptor Binding Domain ◽  
Recent Infection

We measured plasma and/or serum antibody responses to the receptor-binding domain (RBD) of the spike (S) protein of SARS-CoV-2 in 343 North American patients infected with SARS-CoV-2 (of which 93% required hospitalization) up to 122 days after symptom onset and compared them to responses in 1548 individuals whose blood samples were obtained prior to the pandemic. After setting seropositivity thresholds for perfect specificity (100%), we estimated sensitivities of 95% for IgG, 90% for IgA, and 81% for IgM for detecting infected individuals between 15 and 28 days after symptom onset. While the median time to seroconversion was nearly 12 days across all three isotypes tested, IgA and IgM antibodies against RBD were short-lived with median times to seroreversion of 71 and 49 days after symptom onset. In contrast, anti-RBD IgG responses decayed slowly through 90 days with only 3 seropositive individuals seroreverting within this time period. IgG antibodies to SARS-CoV-2 RBD were strongly correlated with anti-S neutralizing antibody titers, which demonstrated little to no decrease over 75 days since symptom onset. We observed no cross-reactivity of the SARS-CoV-2 RBD-targeted antibodies with other widely circulating coronaviruses (HKU1, 229 E, OC43, NL63). These data suggest that RBD-targeted antibodies are excellent markers of previous and recent infection, that differential isotype measurements can help distinguish between recent and older infections, and that IgG responses persist over the first few months after infection and are highly correlated with neutralizing antibodies.

scholarly journals Chemical modification of the adeno-associated virus capsid to improve gene delivery

2020 ◽  
Vol 11 (4) ◽  
pp. 1122-1131 ◽  
Author(s):  
Mathieu Mével ◽  
Mohammed Bouzelha ◽  
Aurélien Leray ◽  
Simon Pacouret ◽  
Mickael Guilbaud ◽  
...  
Keyword(s):  
Gene Delivery ◽  
Chemical Modification ◽  
Neutralizing Antibodies ◽  
Cell Tropism ◽  
Amino Groups ◽  
Chemical Modifications ◽  
Virus Capsid ◽  
Adeno Associated Virus

Bioconjugated AAV vectors, achieved by coupling of ligands on amino groups of the capsid, are of great interest for gene delivery. Chemical modifications can be used to enhance cell tropism and to decrease interactions with neutralizing antibodies.

scholarly journals Enhancement of Muscle Gene Delivery with Pseudotyped Adeno-Associated Virus Type 5 Correlates with Myoblast Differentiation

2001 ◽  
Vol 75 (16) ◽  
pp. 7662-7671 ◽  
Author(s):  
Dongsheng Duan ◽  
Ziying Yan ◽  
Yongping Yue ◽  
Wei Ding ◽  
John F. Engelhardt
Keyword(s):  
Gene Therapy ◽  
Clinical Trials ◽  
Gene Delivery ◽  
Muscle Cells ◽  
Therapeutic Benefit ◽  
Transduction Efficiency ◽  
Great Promise ◽  
Adeno Associated Virus ◽  
Muscle Gene ◽  
Duchenne's Muscular Dystrophy

ABSTRACT Adeno-associated virus (AAV)-based muscle gene therapy has achieved tremendous success in numerous animal models of human diseases. Recent clinical trials with this vector have also demonstrated great promise. However, to achieve therapeutic benefit in patients, large inocula of virus will likely be necessary to establish the required level of transgene expression. For these reasons, efforts aimed at increasing the efficacy of AAV-mediated gene delivery to muscle have the potential for improving the safety and therapeutic benefit in clinical trials. In the present study, we compared the efficiency of gene delivery to mouse muscle cells for recombinant AAV type 2 (rAAV-2) and rAAV-2cap5 (AAV-2 genomes pseudo-packaged into AAV-5 capsids). Despite similar levels of transduction by these two vectors in undifferentiated myoblasts, pseudotyped rAAV-2cap5 demonstrated dramatically enhanced transduction in differentiated myocytes in vitro (>500-fold) and in skeletal muscle in vivo (>200-fold) compared to rAAV-2. Serotype-specific differences in transduction efficiency did not directly correlate with viral binding to muscle cells but rather appeared to involve endocytic or intracellular barriers to infection. Furthermore, application of this pseudotyped virus in a mouse model of Duchenne's muscular dystrophy also demonstrated significantly improved transduction efficiency. These findings should have a significant impact on improving rAAV-mediated gene therapy in muscle.

scholarly journals Universal protection against influenza infection by a multidomain antibody to influenza hemagglutinin

Science ◽  
2018 ◽  
Vol 362 (6414) ◽  
pp. 598-602 ◽  
Author(s):  
Nick S. Laursen ◽  
Robert H. E. Friesen ◽  
Xueyong Zhu ◽  
Mandy Jongeneelen ◽  
Sven Blokland ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Neutralizing Antibodies ◽  
Influenza A ◽  
Influenza Infection ◽  
Cross Reactivity ◽  
Broadly Neutralizing Antibodies ◽  
Adeno Associated Virus ◽  
Influenza Hemagglutinin ◽  
Influenza Virus Hemagglutinin ◽  
Single Domain Antibodies

Broadly neutralizing antibodies against highly variable pathogens have stimulated the design of vaccines and therapeutics. We report the use of diverse camelid single-domain antibodies to influenza virus hemagglutinin to generate multidomain antibodies with impressive breadth and potency. Multidomain antibody MD3606 protects mice against influenza A and B infection when administered intravenously or expressed locally from a recombinant adeno-associated virus vector. Crystal and single-particle electron microscopy structures of these antibodies with hemagglutinins from influenza A and B viruses reveal binding to highly conserved epitopes. Collectively, our findings demonstrate that multidomain antibodies targeting multiple epitopes exhibit enhanced virus cross-reactivity and potency. In combination with adeno-associated virus–mediated gene delivery, they may provide an effective strategy to prevent infection with influenza virus and other highly variable pathogens.

scholarly journals 727. Characterizing the Adeno-Associated Virus 1 Sialic Receptor Binding Site and Its Overlap with Antigenic Epitopes

2016 ◽  
Vol 24 ◽  
pp. S287
Author(s):  
Lin-Ya Huang ◽  
Ami Patel ◽  
Robert Ng ◽  
Edward B. Miller ◽  
Sujata Halder ◽  
...  
Keyword(s):  
Binding Site ◽  
Receptor Binding ◽  
Receptor Binding Site ◽  
Adeno Associated Virus ◽  
Antigenic Epitopes

scholarly journals Assessment of Romiplostim Immunogenicity in Pediatric Patients in Clinical Trials and in a Global Postmarketing Registry

2021 ◽  
Author(s):  
Charles Bowers ◽  
Daniel T. Mytych ◽  
Tatiana Cristina Lawrence ◽  
Kejia Wang ◽  
Troy E. Barger ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Platelet Count ◽  
Neutralizing Antibodies ◽  
Receptor Agonist ◽  
Immune Thrombocytopenia ◽  
First Generation ◽  
Pediatric Patients ◽  
Cross Reactivity ◽  
Platelet Response ◽  
Primary Immune Thrombocytopenia

Development of first-generation thrombopoietins (TPOs) was halted due to antibodies that neutralized endogenous TPO, causing protracted thrombocytopenia in some patients. The second-generation TPO receptor agonist romiplostim, having no homology to TPO, was developed to circumvent potential immunogenicity. We examined development of binding and neutralizing antibodies to romiplostim and TPO among pediatric patients with primary immune thrombocytopenia (ITP) in 5 trials and a global postmarketing registry. In the trials, 25/280 (8.9%) patients developed anti-romiplostim binding antibodies. The first positive result was detected 67 weeks (median) after starting romiplostim; median romiplostim dose was 8 µg/kg and median platelet count 87 x 109/L. Most patients who developed anti-romiplostim binding antibodies (18/25 [72%]) had ≥ 90% platelet assessments showing response. Anti-romiplostim neutralizing antibodies developed in 8/280 (2.9%) patients; this was unrelated to romiplostim dose, and most patients who developed anti-romiplostim neutralizing antibodies (7/8 [88%]) had platelet response. Nine of 279 (3.2%) patients developed anti-TPO binding antibodies, and 1 (0.4%) developed transient anti-TPO neutralizing antibodies. In 8 patients who developed anti-romiplostim neutralizing antibodies, no TPO cross-reactivity was observed. In the postmarketing registry, 3/19 (15.8%) patients had anti-romiplostim binding antibodies; 1 (5.3%) had anti-romiplostim neutralizing antibodies. These results show that immunogenicity to romiplostim occurs infrequently in children with ITP and is generally not associated with loss of platelet response or other negative clinical sequelae.

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