Development of nanobodies against Mal de Río Cuarto virus major viroplasm protein P9‑1 for diagnostic sandwich ELISA and immunodetection

Mal de Río Cuarto virus (MRCV) is a member of the genus Fijivirus of the family Reoviridae that causes a devastating disease in maize and is persistently and propagatively transmitted by planthopper vectors. Virus replication and assembly occur within viroplasms formed by viral and host proteins. This work describes the isolation and characterization of llama-derived Nanobodies (Nbs) recognizing the major viral viroplasm component, P9-1. Specific Nbs were selected against recombinant P9-1, with affinities in the nanomolar range as measured by surface plasmon resonance. Three selected Nbs were fused to alkaline phosphatase and eGFP to develop a sandwich ELISA test which showed a high diagnostic sensitivity (99.12%, 95% CI 95.21–99.98) and specificity (100%, 95% CI 96.31–100) and a detection limit of 0.236 ng/ml. Interestingly, these Nanobodies recognized different P9-1 conformations and were successfully employed to detect P9-1 in pull-down assays of infected maize extracts. Finally, we demonstrated that fusions of the Nbs to eGFP and RFP allowed the immunodetection of virus present in phloem cells of leaf thin sections. The Nbs developed in this work will aid the study of MRCV epidemiology, assist maize breeding programs, and be valuable tools to boost fundamental research on viroplasm structure and maturation.Instituto de BiotecnologíaFil: Llauger, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Llauger, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Monti, Demian Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Monti, Demian Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aduriz Guerrero, Matí­as. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; ArgentinaFil: Aduriz Guerrero, Matí­as. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romão, Ema. Vrije Universiteit Brussel. Lab of Cellular and Molecular Immunology; BélgicaFil: Dumon, Analia Delina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Dumon, Analia Delina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mattio, Maria Fernanda. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Mattio, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wigdorovitz, Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). INCUINTA. Instituto de Virología e Innovaciones Tecnológicas; ArgentinaFil: Wigdorovitz, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Muyldermans, Serge. Vrije Universiteit Brussel. Lab of Cellular and Molecular Immunology; BélgicaFil: Muyldermans, Serge. Dalian University of Technology. School of Bioengineering. Liaoning Key Laboratory of Molecular Recognition and Imaging; ChinaFil: Vincke, Cécile. Vrije Universiteit Brussel. Lab of Cellular and Molecular Immunology; BélgicaFil: Vincke, Cécile. VIB Center for Inflammation Research. Myeloid Cell Immunology Lab; BélgicaFil: Parreño, Viviana. Instituto Nacional de Tecnología Agropecuaria (INTA). INCUINTA. Instituto de Virología e Innovaciones Tecnológicas; ArgentinaFil: Parreño, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Del Vas, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Del Vas, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Development of nanobodies against hemorrhagic and myotoxic components of Bothrops atrox snake venom

Snake envenoming is a globally neglected public health problem. Antivenoms produced using animal hyperimmune plasma remain the standard therapy for snakebites. Although effective against systemic effects, conventional antivenoms have limited efficacy against local tissue damage. In addition, potential hypersensitivity reactions, high costs for animal maintenance, and difficulties in obtaining batch-to-batch homogeneity are some of the factors that have motivated the search for innovative and improved therapeutic products against such envenoming. In this study, we have developed a set of nanobodies (recombinant single-domain antigen-binding fragments from camelid heavy chain-only antibodies) against Bothrops atrox snake venom hemorrhagic and myotoxic components. An immune library was constructed after immunizing a Lama glama with whole venom of B. atrox, from which nanobodies were selected by phage display using partially purified hemorrhagic and myotoxic proteins. Biopanning selections retrieved 18 and eight different nanobodies against the hemorrhagic and the myotoxic proteins, respectively. In vivo assays in mice showed that five nanobodies inhibited the hemorrhagic activity of the proteins; three neutralized the hemorrhagic activity of whole B. atrox venom, while four nanobodies inhibited the myotoxic protein. A mixture of the anti-hemorrhagic and anti-myotoxic nanobodies neutralized the local tissue hemorrhage and myonecrosis induced by the whole venom, although the nanobody mixture failed to prevent the venom lethality. Nevertheless, our results demonstrate the efficacy and usefulness of these nanobodies to neutralize important pathologies of the venom, highlighting their potential as innovative therapeutic agents against envenoming by B. atrox, a viperid species causing many casualties in South America.National Council of Science and Technology/[188-2015-FONDECYT]/CONCYTEC-FONDECYT/PerúUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

AAV-mediated delivery of an anti-BACE1 VHH alleviates pathology in an Alzheimer's disease model

Single domain antibodies (VHHs) are potentially disruptive therapeutics, with important biological value for treatment of several diseases, including neurological disorders. However, VHHs have not been widely used in the central nervous system (CNS), largely because of their restricted blood–brain barrier (BBB) penetration. Here, we propose a gene transfer strategy based on BBB-crossing adeno-associated virus (AAV)-based vectors to deliver VHH directly into the CNS. As a proof-of-concept, we explored the potential of AAV-delivered VHH to inhibit BACE1, a well-characterized target in Alzheimer’s disease. First, we generated a panel of VHHs targeting BACE1, one of which, VHH-B9, shows high selectivity for BACE1 and efficacy in lowering BACE1 activity in vitro. We further demonstrate that a single systemic dose of AAV-VHH-B9 produces positive long-term (12 months plus) effects on amyloid load, neuroinflammation, synaptic function, and cognitive performance, in the AppNL-G-F Alzheimer’s mouse model. These results constitute a novel therapeutic approach for neurodegenerative diseases, which is applicable to a range of CNS disease targets

The Development and Validation of a Novel Nanobody-Based Competitive ELISA for the Detection of Foot and Mouth Disease 3ABC Antibodies in Cattle

Effective management of foot and mouth disease (FMD) requires diagnostic tests to distinguish between infected and vaccinated animals (DIVA). To address this need, several enzyme-linked immunosorbent assay (ELISA) platforms have been developed, however, these tests vary in their sensitivity and specificity and are very expensive for developing countries. Camelid-derived single-domain antibodies fragments so-called Nanobodies, have demonstrated great efficacy for the development of serological diagnostics. This study describes the development of a novel Nanobody-based FMD 3ABC competitive ELISA, for the serological detection of antibodies against FMD Non-Structural Proteins (NSP) in Uganda cattle herds. This in-house ELISA was validated using more than 600 sera from different Uganda districts, and virus serotype specificities. The evaluation of the performance of the assay demonstrated high diagnostic sensitivity and specificity of 94 % (95 % CI: 88.9–97.2), and 97.67 % (95 % CI: 94.15–99.36) respectively, as well as the capability to detect NSP-specific antibodies against multiple FMD serotype infections. In comparison with the commercial PrioCHECK FMDV NSP-FMD test, there was a strong concordance and high correlation and agreement in the performance of the two tests. This new developed Nanobody based FMD 3ABC competitive ELISA could clearly benefit routine disease diagnosis, the establishment of disease-free zones, and the improvement of FMD management and control in endemically complex environments, such as those found in Africa

Inhibiting the Ca2+ Influx Induced by Human CSF.

One potential therapeutic strategy for Alzheimer's disease (AD) is to use antibodies that bind to small soluble protein aggregates to reduce their toxic effects. However, these therapies are rarely tested in human CSF before clinical trials because of the lack of sensitive methods that enable the measurement of aggregate-induced toxicity at low concentrations. We have developed highly sensitive single vesicle and single-cell-based assays that detect the Ca2+ influx caused by the CSF of individuals affected with AD and healthy controls, and we have found comparable effects for both types of samples. We also show that an extracellular chaperone clusterin; a nanobody specific to the amyloid-β peptide (Aβ); and bapineuzumab, a humanized monoclonal antibody raised against Aβ, could all reduce the Ca2+ influx caused by synthetic Aβ oligomers but are less effective in CSF. These assays could be used to characterize potential therapeutic agents in CSF before clinical trials

The Development and Validation of a Novel Nanobody-Based Competitive ELISA for the Detection of Foot and Mouth Disease 3ABC Antibodies in Cattle

Effective management of foot and mouth disease (FMD) requires diagnostic tests to distinguish between infected and vaccinated animals (DIVA). To address this need, several enzyme-linked immunosorbent assay (ELISA) platforms have been developed, however, these tests vary in their sensitivity and specificity and are very expensive for developing countries. Camelid-derived single-domain antibodies fragments so-called Nanobodies, have demonstrated great efficacy for the development of serological diagnostics. This study describes the development of a novel Nanobody-based FMD 3ABC competitive ELISA, for the serological detection of antibodies against FMD Non-Structural Proteins (NSP) in Uganda cattle herds. This in-house ELISA was validated using more than 600 sera from different Uganda districts, and virus serotype specificities. The evaluation of the performance of the assay demonstrated high diagnostic sensitivity and specificity of 94 % (95 % CI: 88.9-97.2), and 97.67 % (95 % CI: 94.15-99.36) respectively, as well as the capability to detect NSP-specific antibodies against multiple FMD serotype infections. In comparison with the commercial PrioCHECK FMDV NSP-FMD test, there was a strong concordance and high correlation and agreement in the performance of the two tests. This new developed Nanobody based FMD 3ABC competitive ELISA could clearly benefit routine disease diagnosis, the establishment of disease-free zones, and the improvement of FMD management and control in endemically complex environments, such as those found in Africa

Quand la délocalisation numérique d’une partie d’un dispositif d’apprentissage permet de recentrer le temps présentiel sur un obstacle : exemple de l’appropriation de la courbe de Gauss par la manipulation d’objets concrets

Les biostatistiques traitent les observations numériques réalisées sur le vivant. La référence à un modèle, telle la gaussienne, objet de cet article, représente pour notre public cible un obstacle épistémologique lié à son inaptitude à la modélisation mathématique. Les ostensifs graphiques interactifs sur lesquels repose notre dispositif didactique développé sur le Web lui restant encore peu accessibles, leur appropriation est assurée par la mesure d’objets et la transposition des données réelles d’un tableur en histogrammes concrets. Cette approche pratique n’a pu être mise en place que par la libération de temps didactique, inhérente à la délocalisation numérique d’une partie du dispositif original