SARS-CoV-2 antibodies and COVID-19 severity

Background: The involvement of SARS-CoV-2 antibodies in mediating immunopathogenetic events in COVID-19 patients has been suggested. By using several experimental approaches, we investigated the potential association between SARS-CoV-2 IgGs recognizing the spike (S) protein receptor-binding domain (RBD), neutralizing antibodies (NtAb) targeting S, and COVID-19 severity. Patients and Methods: This unicenter, retrospective, observational study included 51 hospitalized patients (24 at the intensive care unit; ICU). A total of 93 sera from these patients collected at different time points from the onset of symptoms were analyzed. SARS-CoV-2 RBD IgGs were quantitated by ELISA and NtAb50 titers were measured in a GFP reporter-based pseudotyped virus platform. Demographic and clinical data, complete blood counts, as well as serum levels of ferritin, Dimer-D, C reactive protein (CRP), lactose dehydrogenase (LDH), and interleukin-6 (IL-6) were retrieved from clinical charts. Results: The overall correlation between levels of both antibody measurements was good (Rho=0.79; P=00.1). The percentage of patients who exhibited high NtAb50 titers (≥160) was similar (P=0.20) in ICU (79%) and non-ICU (60%) patients. Four ICU patients died; two of these achieved NtAb50 titers ≥1/160 while the other two exhibited a 1/80 titer. Very weak (Rho=>0.0-0.2-<0.4) correlations were observed between anti-RBD IgGs, NtAb50, and serum levels pro-inflammatory biomarkers. Conclusions: The data presented herein do not support an association between SARS-CoV-2 RBD IgG or NtAb50 levels and COVID-19 severityThis work was supported by a grant from the Generalitat Valenciana (Covid_19-SCI) to RG, and a grant by Valencian Government grant DIFEDER/2018/056 to JRD.N

Un ataque combinado químico, virológico, biofísico y estructural hace posible la obtención de nuevos inhibidores de entrada celular de SARS-CoV-2 y la caracterización de su mecanismo de inhibición

Resumen del trabajo presentado al 45º Congreso de la Sociedad Española de Bioquímica y Biología Molecular (SEBBM), celebrado en Zaragoza del 5 al 8 de septiembre de 2023.IBV-COVID19 Pipeline: C.Espinosa, N.Gougeard, M.P.Hernández-Sierra, A.Rubio-del-Campo, R.Ruiz-Partida, L.Villamayor.El virus SARS-CoV-2 causa el COVID-19 al infectar las células a través de la interacción de la proteína de su espícula (S) con el receptor celular enzima convertidora de angiotensina 2 (ACE2). Para buscar inhibidores de este paso clave en la infección viral, examinamos una biblioteca interna (IQM-CSIC, Madrid) de compuestos multivalentes derivados de triptófano, primero usando pseudopartículas de Virus de Estomatits Vesicular que expresaban S (I2SysBio, UV y CSIC, Valencia), identificando un compuesto como potente inhibidor de entrada no citotóxico. La optimización química (IQM-CSIC) generó otros dos potentes inhibidores de entrada no citotóxicos que, como 2, también inhibieron la entrada celular de SARS-CoV-2 genuino (I2SysBio). Los estudios con proteínas recombinantes puras (IBV-CSIC, Valencia) usando termofluor y termoforesis de microescala revelaron la unión de estos compuestos a S, y a su dominio de unión al receptor producido separadamente, probando interferencia con la interacción con ACE2. La criomicroscopía electrónica de S (IBV-CSIC), libre o unido al compuesto activo, arrojó luz sobre los mecanismos de inhibición por estos compuestos de la entrada viral a la célula. Esta actividad triinstitucional combinada ha identificado y caracterizado una nueva clase de inhibidores de entrada de SARS-CoV-2 de claro potencial preventivo o terapéutico de COVID-19.ECNextGeneration EUfund 2020/2094 de CSIC/PTI Salud Global; Crue/CSIC/Santander Fondo Supera Covid-19;CSIC-COV19-082; CIBERER-ISCIIICOV20/00437; Covid19-SCI/GValenciana (RG);PID2020- 120322RB-C21 (VR) y PID2020-116880GB-I00 (JLLl) Agenc. Estat Investig.Peer reviewe

The structural role of SARS-CoV-2 genetic background in the emergence and success of spike mutations: The case of the spike A222V mutation

The S:A222V point mutation, within the G clade, was characteristic of the 20E (EU1) SARS-CoV-2 variant identified in Spain in early summer 2020. This mutation has since reappeared in the Delta subvariant AY.4.2, raising questions about its specific effect on viral infection. We report combined serological, functional, structural and computational studies characterizing the impact of this mutation. Our results reveal that S:A222V promotes an increased RBD opening and slightly increases ACE2 binding as compared to the parent S:D614G clade. Finally, S:A222V does not reduce sera neutralization capacity, suggesting it does not affect vaccine effectiveness

Preservation of anti-SARS-CoV-2 neutralising antibodies in convalescent plasma after pathogen reduction with methylene blue and visible light

Background - COVID-19 convalescent plasma (CCP) is an experimental treatment against SARS-CoV-2. Although there has so far been no evidence of transmission through transfusion, pathogen reduction technologies (PRT) have been applied to CCP to mitigate risk of infectious disease. This study aims to assess the impact of methylene blue (MB) plus visible light PRT on the virus-neutralising activity of the specific antibodies against SARS-CoV-2. Material and methods - Thirty-five plasma doses collected by plasmapheresis from COVID-19 convalescent donors were subjected to MB plus visible light PRT. Anti-SARS-CoV-2 RBD S1 epitope IgGs antibodies were quantified by ELISA. Titres of SARS-CoV-2 neutralising antibodies (NtAbs) were measured before and after the PRT process. A Spearman's correlation was run to determine the relationship between antibody neutralisation ability and SARS-CoV-2 IgG ELISA ratio. Pre- and post-inactivation neutralising antibody titres were evaluated using a Wilcoxon test. Results - The plasma pathogen reduction procedure did not diminish NtAbS titres and so did not cause a change in the viral neutralisation capacity of CCP. There was a strong correlation between pre-and post-PRT NtAbs and anti-SARS-CoV-2 IgGs titres. Discussion - Our results showed PRT with MB did not impair the CCP passive immunity preserving its potential therapeutic potency. Therefore, PRT of CCP should be recommended to mitigate the risk for transmission of transfusionassociated infectious disease. There is a good correlation between SARS-CoV-2 IgG titres determined by ELISA and the neutralising capacity. This allows blood centres to select CCP donors based on IgG ELISA titres avoiding the much more labour-intensive laboratory processes for determining neutralising antibodies.Peer reviewe

The structural role of SARS-CoV-2 genetic background in the emergence and success of spike mutations: the case of the spike A222V mutation

The S:A222V point mutation, within the G clade, was characteristic of the 20E (EU1) SARS-CoV-2 variant identified in Spain in early summer 2020. This mutation has now reappeared in the Delta subvariant AY.4.2, raising questions about its specific effect on viral infection. We report combined serological, functional, structural and computational studies characterizing the impact of this mutation. Our results reveal that S:A222V promotes an increased RBD opening and slightly increases ACE2 binding as compared to the parent S:D614G clade. Finally, S:A222V does not reduce sera neutralization capacity, suggesting it does not affect vaccine effectiveness.This research work was supported by the European Commission–NextGenerationEU through the CSIC Global Health Platform. Additionally, authors would like to acknowledge economic support from the Spanish Ministry of Science and Innovation through Grants: PID2019-104757RB-I00 funded by MCIN/AEI/ 10.13039/501100011033, RTI2018-094399-A-I00, and “ERDF A way of making Europe”, by the “European Union”, Grant SEV 2017-0712 funded by MCIN/AEI /10.13039/501100011033, the “Comunidad Autónoma de Madrid" through Grant: S2017/BMD3817, and the European Union (EU) and Horizon 2020 through grants: Marie-Curie Fellowship EnLaCES (MSCA IF 2020, Proposal: 101024130) (to JK), HighResCells (ERC - 2018 - SyG, Proposal: 810057), and iNEXT-Discovery (Proposal: 871037). AM, VR, JB and JLL are funded by CIBERER-ISCIII (proposal: COV20/00437), Fondo Supera COVID-19 (proposal: CSICCOVID19-082), Banco Santander (Proposal: BlockAce), and CSIC PTI Salud Global (Proposal: 202080E110). VR is funded by the Spanish Ministry of Science and Innovation through Grant PID2020-120322RB-C21. IC is funded by project PID2019-104477RB-100, Fondo COVID COV20/00140 and ERC CoG 101001038. MC is funded by the RyC program from the Spanish Ministry of Science and Innovation, the Generalitat Valenciana (SEJI/2019/011).N

The role of SARS-CoV-2 genetic background in the emergence and success of spike mutations: the case of the spike A222V mutation

Resumen del trabajo presentado a las II Jornadas Científicas PTI + Salud Global, celebradas los días 5 y 6 de octubre de 2022 en el Auditorio Santiago Grisolía de Valencia (España).Peer reviewe

Evolutionary genomics of SARS-CoV-2: keys for viral success

Resumen del trabajo presentado al 44º Congreso de la Sociedad Española de Bioquímica y Biología Molecular, celebrado en Málaga del 6 al 9 de septiembre de 2022.Peer reviewe

Genomic surveillance and impact of SARS-CoV-2 mutations

Resumen del póster presentado a las II Jornadas Científicas PTI + Salud Global, celebradas los días 5 y 6 de octubre de 2022 en el Auditorio Santiago Grisolía de Valencia (España).Peer reviewe

Antigens from the Helminth Fasciola hepatica Exert Antiviral Effects against SARS-CoV-2 In Vitro

SARS-CoV-2, the causal agent of COVID-19, is a new coronavirus that has rapidly spread worldwide and significantly impacted human health by causing a severe acute respiratory syndrome boosted by a pulmonary hyperinflammatory response. Previous data from our lab showed that the newly excysted juveniles of the helminth parasite Fasciola hepatica (FhNEJ) modulate molecular routes within host cells related to vesicle-mediated transport and components of the innate immune response, which could potentially be relevant during viral infections. Therefore, the aim of the present study was to determine whether FhNEJ-derived molecules influence SARS-CoV-2 infection efficiency in Vero cells. Pre-treatment of Vero cells with a tegument-enriched antigenic extract of FhNEJ (FhNEJ-TEG) significantly reduced infection by both vesicular stomatitis virus particles pseudotyped with the SARS-CoV-2 Spike protein (VSV-S2) and live SARS-CoV-2. Pre-treatment of the virus itself with FhNEJ-TEG prior to infection also resulted in reduced infection efficiency similar to that obtained by remdesivir pre-treatment. Remarkably, treatment of Vero cells with FhNEJ-TEG after VSV-S2 entry also resulted in reduced infection efficiency, suggesting that FhNEJ-TEG may also affect post-entry steps of the VSV replication cycle. Altogether, our results could potentially encourage the production of FhNEJ-derived molecules in a safe, synthetic format for their application as therapeutic agents against SARS-CoV-2 and other related respiratory viruses

Bacteroides uniformis combined with fiber amplifies metabolic and immune benefits in obese mice

Gut microbiota represents a therapeutic target for obesity. We hypothesize that B. uniformis CECT 7771 combined with wheat bran extract (WBE), its preferred carbon source, may exert superior anti-obesity effects. We performed a 17-week intervention in diet-induced obese mice receiving either B. uniformis, WBE, or their combination to identify interactions and independent actions on metabolism and immunity. B. uniformis combined with WBE was the most effective intervention, curbing weight gain and adiposity, while exerting more modest effects separately. The combination restored insulin-dependent metabolic routes in fat and liver, although the bacterium was the primary driver for improving whole-body glucose disposal. Moreover, B. uniformis-combined with WBE caused the highest increases in butyrate and restored the proportion of induced intraepithelial lymphocytes and type-3 innate lymphoid cells in the intestinal epithelium. Thus, strengthening the first line of immune defense against unhealthy diets and associated dysbiosis in the intestine. This intervention also attenuated the altered IL22 signaling and liver inflammation. Our study shows opportunities for employing B. uniformis, combined with WBE, to aid in the treatment of obesity