Harnessing preexisting influenza virus-specific immunity increases antibody responses against SARS-CoV-2.

In pandemic scenarios involving novel human pathogenic viruses, it is highly desirable that vaccines induce strong neutralizing antibodies as quickly as possible. However, current vaccine strategies require multiple immunization doses to produce high titers of neutralizing antibodies and are poorly protective after a single vaccination. We therefore wished to design a vaccine candidate that would induce increased protective immune responses following the first vaccine dose. We hypothesized that antibodies against the receptor-binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein could be increased by drawing upon immunity to a previous infection. We generated a fusion protein containing the influenza H1N1 PR8 virus nucleoprotein (NP) and the SARS-CoV-2 spike RBD. Mice with or without preexisting immunity to PR8 were then vaccinated with NP/RBD. We observed significantly increased SARS-CoV-2 neutralizing antibodies in mice with PR8 immunity compared to mice without preexisting PR8 immunity. Vaccination with NP/RBD protected mice from SARS-CoV-2-induced morbidity and mortality after a single dose. Additionally, we compared SARS-CoV-2 virus titers in the lungs and nasal turbinates 4 days post-challenge of mice vaccinated with NP/RBD. SARS-CoV-2 virus was detectable in the lungs and nasal turbinate of mice without preexisting PR8 immunity, while SARS-CoV-2 virus was completely undetectable in mice with preexisting PR8 immunity. We also found that CD4-positive T cells in mice with preexisting immunity to PR8 play an essential role in producing the increased antibody response against RBD. This vaccine strategy potentially can be modified to target other pathogens of concern and offers extra value in future pandemic scenarios.IMPORTANCEIncreased globalization and changes in human interactions with wild animals has increased the likelihood of the emergence of novel viruses with pandemic potential. Vaccines can be effective in preventing severe disease caused by pandemic viruses. However, it takes time to develop protective immunity via prime-boost vaccination. More effective vaccine designs should quickly induce protective immunity. We propose leveraging preexisting immunity to a different pathogen to boost protection against emerging viruses. We targeted SARS-CoV-2 as a representative pandemic virus and generated a fusion protein vaccine that combines the nucleoprotein from influenza A virus and the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. Our vaccine design significantly increased the production of RBD-specific antibodies in mice that had previously been exposed to influenza virus, compared to those without previous exposure. This enhanced immunity reduced SARS-CoV-2 replication in mice. Our results offer a vaccine design that could be valuable in a future pandemic setting.

Report on influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza during 2022.

As part of its role in the World Health Organization's (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received a record total of 12,073 human influenza positive samples during 2022. Viruses were analysed for their antigenic, genetic and antiviral susceptibility properties. Selected viruses were propagated in qualified cells or embryonated hen's eggs for potential use in seasonal influenza virus vaccines. In 2022, influenza A(H3N2) viruses predominated over influenza A(H1N1)pdm09 and B viruses, accounting for 77% of all viruses analysed. The majority of A(H1N1)pdm09, A(H3N2) and influenza B viruses analysed at the Centre were found to be antigenically and genetically similar to the respective WHO recommended vaccine strains for the southern hemisphere in 2022. Of 3,372 samples tested for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir, two A(H1N1)pdm09 viruses showed highly reduced inhibition against oseltamivir.

Efficacy and effectiveness of influenza vaccination in healthy children. A review of current evidence / Eficacia y efectividad de la vacunación frente a la gripe en niños sanos. Una revisión de la evidencia actual

Influenza is common in healthy children and adolescents and is associated with a high rate of hospitalization in this group, especially for those <5 years. Although the WHO has recommended vaccination in children under 5 years of age since 2012, it is really implemented in few countries today. The aim of this paper was to review the available evidence on the efficacy/effectiveness of influenza vaccination in healthy children <18 years of age through a non-systematic search of studies conducted between 2010 and 2020. Despite the high variability in results due to differences in design, vaccine type and season included in the 41 selected studies, statistically significant studies show efficacy values for the influenza vaccine of between 25.6% and 74.2%, and effectiveness from 26% to 78.8%. Although a systematic review would be necessary to corroborate the evidence, this review suggests that paediatric vaccination is generally an effective measure for preventing influenza in healthy children in line with international organisms’ recommendations.(AU)

La gripe tiene una elevada incidencia en niños y adolescentes sanos, y se asocia a una alta tasa de hospitalización, especialmente en los < 5 años. Desde 2012, la Organización Mundial de la Salud recomienda la vacunación en < 5 años, pero pocos países aplican hoy esta recomendación. El objetivo de este documento es revisar la evidencia disponible sobre la eficacia/efectividad de la vacunación antigripal en niños sanos < 18 años mediante una búsqueda no sistemática de estudios entre 2010-2020. A pesar de la gran variabilidad en los resultados debido a las diferencias de diseño, tipo de vacuna y temporada incluidos en los 41 estudios seleccionados, aquellos con significación estadística muestran valores de eficacia para la vacuna antigripal del 25,6% y al 74,2%, y de efectividad del 26% al 78,8%. Aunque sería necesaria una revisión sistemática para corroborar la evidencia, esta revisión sugiere que la vacunación pediátrica es globalmente una medida eficaz/efectiva para prevenir la gripe en niños sanos, en línea con las recomendaciones de organismos internacionales.(AU)

Acontecimientos adversos en embarazadas con la vacuna tetravalente contra la gripe obtenida de cultivos celulares / Adverse events in pregnant women with the tetravalent influenza vaccine obtained from cell cultures

La vacunación de la gripe en embarazadas muestra una clara relación beneficio/riesgo. En la actualidad se están desarrollando vacunas contra la gripe utilizando nuevas plataformas. Es imprescindible analizar la seguridad de estas nuevas vacunas en este grupo poblacional, infrarrepresentado en los ensayos clínicos. En la temporada 2019-2020 se aconsejó una vacuna obtenida en cultivo celular a las embarazadas en 2comunidades autónomas. Se recogió información de los centros de vacunación y de farmacovigilancia de ambas comunidades. La tasa de notificación de casos de acontecimientos adversos tras la vacunación en embarazadas fue de 4,02/100.000 dosis administradas y, en mujeres de 18 a 64 años no embarazadas, de 5,9/100.000 dosis administradas. La tasa de acontecimientos adversos notificados fue de 8,04 y 17,74, respectivamente. No se notificaron abortos espontáneos, prematuridad ni malformaciones fetales. Este análisis señala la seguridad en embarazadas de la vacuna de la gripe obtenida de cultivos celulares.(AU)

Influenza vaccination in pregnant women shows a clear benefit/risk ratio. Influenza vaccines are currently being developed using new platforms. It is essential to analyze the safety of these new vaccines in this population group, underrepresented in clinical trials. In the 2019-2020 season, a vaccine obtained in cell culture was recommended to pregnant women in 2autonomous communities. Information is collected from the vaccination and pharmacovigilance centers of both communities. The reporting rate of adverse events after vaccination in pregnant women was 4.02/100,000 doses administered, and in non-pregnant women aged 18-64 years it was 5.9/100,000 doses administered. The rate of adverse events reported was 8.04 and 17.74, respectively. No spontaneous abortions, prematurity or fetal malformations were reported. This analysis suggests the safety in pregnant women of the influenza vaccine obtained from cell cultures.(AU)

Endothelial AHR activity prevents lung barrier disruption in viral infection.

Disruption of the lung endothelial-epithelial cell barrier following respiratory virus infection causes cell and fluid accumulation in the air spaces and compromises vital gas exchange function1. Endothelial dysfunction can exacerbate tissue damage2,3, yet it is unclear whether the lung endothelium promotes host resistance against viral pathogens. Here we show that the environmental sensor aryl hydrocarbon receptor (AHR) is highly active in lung endothelial cells and protects against influenza-induced lung vascular leakage. Loss of AHR in endothelia exacerbates lung damage and promotes the infiltration of red blood cells and leukocytes into alveolar air spaces. Moreover, barrier protection is compromised and host susceptibility to secondary bacterial infections is increased when endothelial AHR is missing. AHR engages tissue-protective transcriptional networks in endothelia, including the vasoactive apelin-APJ peptide system4, to prevent a dysplastic and apoptotic response in airway epithelial cells. Finally, we show that protective AHR signalling in lung endothelial cells is dampened by the infection itself. Maintenance of protective AHR function requires a diet enriched in naturally occurring AHR ligands, which activate disease tolerance pathways in lung endothelia to prevent tissue damage. Our findings demonstrate the importance of endothelial function in lung barrier immunity. We identify a gut-lung axis that affects lung damage following encounters with viral pathogens, linking dietary composition and intake to host fitness and inter-individual variations in disease outcome.

Immunological profile of mice immunized with a polyvalent virosome-based influenza vaccine.

BACKGROUND: Influenza A virus (IAV) causes respiratory disease in pigs and is a major concern for public health. Vaccination of pigs is the most successful measure to mitigate the impact of the disease in the herds. Influenza-based virosome is an effective immunomodulating carrier that replicates the natural antigen presentation pathway and has tolerability profile due to their purity and biocompatibility. METHODS: This study aimed to develop a polyvalent virosome influenza vaccine containing the hemagglutinin and neuraminidase proteins derived from the swine IAVs (swIAVs) H1N1, H1N2 and H3N2 subtypes, and to investigate its effectiveness in mice as a potential vaccine for swine. Mice were immunized with two vaccine doses (1 and 15 days), intramuscularly and intranasally. At 21 days and eight months later after the second vaccine dose, mice were euthanized. The humoral and cellular immune responses in mice vaccinated intranasally or intramuscularly with a polyvalent influenza virosomal vaccine were investigated. RESULTS: Only intramuscular vaccination induced high hemagglutination inhibition (HI) titers. Seroconversion and seroprotection (> 4-fold rise in HI antibody titers, reaching a titer of ≥ 1:40) were achieved in 80% of mice (intramuscularly vaccinated group) at 21 days after booster immunization. Virus-neutralizing antibody titers against IAV were detected at 8 months after vaccination, indicating long-lasting immunity. Overall, mice immunized with the virosome displayed greater ability for B, effector-T and memory-T cells from the spleen to respond to H1N1, H1N2 and H3N2 antigens. CONCLUSIONS: All findings showed an efficient immune response against IAVs in mice vaccinated with a polyvalent virosome-based influenza vaccine.

Exploring Influenza A Virus-Induced Lung Injury and Immune Response Based on Humanized Lung-on-Chip.

BACKGROUND: Influenza is an important respiratory tract pathogen that causes substantial seasonal and pandemic morbidity and mortality. The aim of this study was to systematically analyze the transcriptome characteristics of peripheral blood mononuclear cells (PBMCs) after influenza A virus infection by constructing a human lung microarray model composed of PBMCs to simulate the influenza A virus infection process. METHODS: A human lung microarray model was constructed using alveolar epithelial cells, vascular endothelial cells, alveolar macrophages and PBMCs, for simulation of the process of influenza A virus infection. The transcriptome characteristics of PBMCs after influenza A virus infection were analyzed by a single-cell RNA sequencing system. RESULTS: The study could realistically mimic the structure and physiological functions of the alveoli in vitro using immunofluorescence staining and expression of the specific marker. After the influenza A virus infected the upper lung chip channels, the epithelial cells underwent a high inflammatory response and spread to endothelial cells. Under experimental conditions, the Influenza A virus infection did not compromise the integrity of epithelial cells, but caused damage to endothelial cells and barrier dysfunction. Single-cell RNA sequencing of PBMCs showed that B and cluster of differentiation 4 (CD4) T cells played important immunomodulatory roles in response to influenza A virus infection, including significantly activating type I interferon signaling pathway, regulating cytokine and chemokine signaling pathway. Especially genes involved in cellular communication were significantly highly expressed post-infection. CONCLUSIONS: All these results suggested that the interactions among immune cells played a crucial role in endothelial cell injury and immune cell recruitment after influenza virus infection. This lung-on-chip infection model combined with single-cell RNA sequencing provided a unique platform that can closely investigate the lung immune response to influenza A virus infection and new therapeutic strategies for influenza.

Evaluación de una intervención comunitaria para incrementar la cobertura vacunal de la gripe en mujeres embarazadas / Evaluation of a community-based intervention to increase influenza vaccination coverage in pregnant women

Objetivo: Conocer el impacto de la intervención educativa realizada sobre los profesionales de una zona básica de salud y su grupo de participación comunitaria, que conforman el grupo intervención (GI), y analizar su repercusión en la cobertura vacunal alcanzada para gripe en el grupo de riesgo (gestantes y puérperas) comparándola con su zona básica vecina, que conforma el grupo control (GC), durante la temporada vacunal 2019/20. Diseño: Estudio cuasiexperimental de intervención comunitaria. Emplazamiento: Dos zonas básicas de salud pertenecientes al departamento de salud Elche-Crevillente, España. Participantes: Gestantes y puérperas de 2 zonas básicas de salud y el grupo de participación comunitaria. Los profesionales de salud directamente relacionados con la campaña vacunal de gripe. Intervenciones: Sesión formativa al GI previa a la campaña de gripe 2019/20. Mediciones principales: Actitudes hacia la vacunación de gripe en profesionales sanitarios mediante el cuestionario validado CAPSVA y la cobertura vacunal de las gestantes y puérperas a través del Registro de Vacunas Nominal y su aceptación a la vacuna en la consulta de la matrona. Resultados: Los datos de cobertura vacunal en gripe registrados en el Registro de Vacunas Nominal para las mujeres gestantes y puérperas fue del 26,4% (n=207) en el GI y del 19,7% (n=144) en el GC (p=0,001), con una razón de incidencia del 1,34, lográndose así un 34% más de vacunación en el GI. La aceptación para la vacunación en las consultas de la matrona también fue elevada, inmunizándose en el GI el 96,5% vs. el 89,0% en el GC, con un RR=1,09 (IC 95% 1,01-1,62).Conclusiones: Estrategias de formación conjunta a profesionales y activos de la comunidad mejoran los resultados de cobertura vacunal.

Objective: To know the impact of the educational intervention carried out on the professionals of a basic health area and their community participation group, which make up the intervention group (IG), and to analyze its repercussion on the vaccination coverage achieved for influenza in the risk group (pregnant and puerperal women) comparing it with its neighboring basic zone, which makes up the control group (CG), during the 2019/20 vaccination season. Design: Quasi-experimental study of community intervention. SiteTwo basic health zones belonging to the Elche-Crevillente health department, Spain. Participants: Pregnant and postpartum women from 2 basic health areas and the community participation group. Health professionals directly related to the flu vaccination campaign. Interventions: Training session for the IG prior to the 2019/20 flu campaign. Main measurements: Attitudes towards influenza vaccination in health professionals through the validated CAPSVA questionnaire and the vaccination coverage of pregnant and postpartum women through the Nominal Vaccine Registry and their acceptance of the vaccine in the midwife's office. Results: The influenza vaccination coverage data recorded in Nominal Vaccine Registry for pregnant and puerperal women was 26.4% (n=207) in the IG and 19.7% (n=144) in the CG (p=0.001), with an incidence ratio of 1.34, thus achieving 34% more vaccination in the IG. Acceptance for vaccination in the midwife's office was also high, with 96.5% immunization in IG vs. 89.0% in CG, with a RR=1.09 (95% CI 1.01-1.62). Conclusions: Joint training strategies for professionals and community assets improve the results of vaccination coverage.(AU)

A pan-influenza antibody inhibiting neuraminidase via receptor mimicry.

Rapidly evolving influenza A viruses (IAVs) and influenza B viruses (IBVs) are major causes of recurrent lower respiratory tract infections. Current influenza vaccines elicit antibodies predominantly to the highly variable head region of haemagglutinin and their effectiveness is limited by viral drift1 and suboptimal immune responses2. Here we describe a neuraminidase-targeting monoclonal antibody, FNI9, that potently inhibits the enzymatic activity of all group 1 and group 2 IAVs, as well as Victoria/2/87-like, Yamagata/16/88-like and ancestral IBVs. FNI9 broadly neutralizes seasonal IAVs and IBVs, including the immune-evading H3N2 strains bearing an N-glycan at position 245, and shows synergistic activity when combined with anti-haemagglutinin stem-directed antibodies. Structural analysis reveals that D107 in the FNI9 heavy chain complementarity-determinant region 3 mimics the interaction of the sialic acid carboxyl group with the three highly conserved arginine residues (R118, R292 and R371) of the neuraminidase catalytic site. FNI9 demonstrates potent prophylactic activity against lethal IAV and IBV infections in mice. The unprecedented breadth and potency of the FNI9 monoclonal antibody supports its development for the prevention of influenza illness by seasonal and pandemic viruses.

Interferon alpha inducible protein 6 is a negative regulator of innate immune responses by modulating RIG-I activation.

Interferons (IFNs), IFN-stimulated genes (ISGs), and inflammatory cytokines mediate innate immune responses, and are essential to establish an antiviral response. Within the innate immune responses, retinoic acid-inducible gene I (RIG-I) is a key sensor of virus infections, mediating the transcriptional induction of IFNs and inflammatory proteins. Nevertheless, since excessive responses could be detrimental to the host, these responses need to be tightly regulated. In this work, we describe, for the first time, how knocking-down or knocking-out the expression of IFN alpha-inducible protein 6 (IFI6) increases IFN, ISG, and pro-inflammatory cytokine expression after the infections with Influenza A Virus (IAV), Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and Sendai Virus (SeV), or poly(I:C) transfection. We also show how overexpression of IFI6 produces the opposite effect, in vitro and in vivo, indicating that IFI6 negatively modulates the induction of innate immune responses. Knocking-out or knocking-down the expression of IFI6 diminishes the production of infectious IAV and SARS-CoV-2, most likely because of its effect on antiviral responses. Importantly, we report a novel interaction of IFI6 with RIG-I, most likely mediated through binding to RNA, that affects RIG-I activation, providing a molecular mechanism for the effect of IFI6 on negatively regulating innate immunity. Remarkably, these new functions of IFI6 could be targeted to treat diseases associated with an exacerbated induction of innate immune responses and to combat viral infections, such as IAV and SARS-CoV-2.

Influenza vaccination reveals sex dimorphic imprints of prior mild COVID-19.

Acute viral infections can have durable functional impacts on the immune system long after recovery, but how they affect homeostatic immune states and responses to future perturbations remain poorly understood1-4. Here we use systems immunology approaches, including longitudinal multimodal single-cell analysis (surface proteins, transcriptome and V(D)J sequences) to comparatively assess baseline immune statuses and responses to influenza vaccination in 33 healthy individuals after recovery from mild, non-hospitalized COVID-19 (mean, 151 days after diagnosis) and 40 age- and sex-matched control individuals who had never had COVID-19. At the baseline and independent of time after COVID-19, recoverees had elevated T cell activation signatures and lower expression of innate immune genes including Toll-like receptors in monocytes. Male individuals who had recovered from COVID-19 had coordinately higher innate, influenza-specific plasmablast, and antibody responses after vaccination compared with healthy male individuals and female individuals who had recovered from COVID-19, in part because male recoverees had monocytes with higher IL-15 responses early after vaccination coupled with elevated prevaccination frequencies of 'virtual memory'-like CD8+ T cells poised to produce more IFNγ after IL-15 stimulation. Moreover, the expression of the repressed innate immune genes in monocytes increased by day 1 to day 28 after vaccination in recoverees, therefore moving towards the prevaccination baseline of the healthy control individuals. By contrast, these genes decreased on day 1 and returned to the baseline by day 28 in the control individuals. Our study reveals sex-dimorphic effects of previous mild COVID-19 and suggests that viral infections in humans can establish new immunological set-points that affect future immune responses in an antigen-agnostic manner.

Sirtuin3 Alleviated Influenza A Virus-Induced Mitochondrial Oxidative Stress and Inflammation in Lung Epithelial Cells via Regulating Poly (ADP-Ribose) Polymerase 1 Activity.

INTRODUCTION: Influenza A virus (IAV) infection causes severe lung inflammation and injury, particularly in children. Sirtuin3 (Sirt3) was confirmed to be effective in protecting the lung against injury. This study aims to explore the function and mechanism of Sirt3 on influenza development in children. METHODS: The Sirt3 level in serum samples from IAV-infected children and lung epithelial cells were detected using RT-qPCR, ELISA, and Western blot assays. Cell viability and apoptosis were determined by MTT and flow cytometry assays. Virus titration was conducted by determining TCID50. Cell inflammatory response was detected by a battery of inflammatory cytokines. The contents of ROS and ATP, mitochondrial membrane potential level, and oxygen-consumption rate were examined to reflect on oxidative stress and mitochondrial dysfunction. The activity of poly (ADP-ribose) polymerase 1 (PARP-1) was measured by colorimetry. RESULTS: Sirt3 was downregulated in IAV-infected children's serum samples and BEAS-2B cells. Overexpression of Sirt3 alleviated IAV replication and IAV-induced inflammatory injury, oxidative stress, and mitochondrial dysfunction in lung epithelial cells. Moreover, upregulation of Sirt3 deacetylated SOD2 and PARP-1 and inhibited the PARP-1 activity. Notably, the Sirt3 inhibitor (3-TYP) and PARP-1 activity agonist (nicotinamide) reversed the effects of Sirt3 overexpression on IAV replication and IAV-induced injury. CONCLUSION: Overexpression of Sirt3 attenuated IAV-evoked inflammatory injury and mitochondrial oxidative stress through the inhibition of PARP-1 activity in lung epithelial cells.

Vacunación contra influenza y neumococo en pacientes con artritis reumatoide / Vaccination against influenza and pneumococus in patients with rheumatoid arthritis

Antecedentes: La vacunación contra agentes infecciosos como influenza y neumococo está ampliamente recomendada para pacientes con artritis reumatoide, no se conoce la prevalencia de adherencia a estos programas de vacunación en México. Métodos: Se realizó un estudio descriptivo trasversal, por medio de aplicación de encuesta a pacientes adultos con diagnóstico de artritis reumatoide atendidos en un hospital de tercer nivel en la Ciudad de México. Resultados: Se incluyeron 227 pacientes, se encontró una prevalencia de vacunación contra influenza en 31,3% y contra neumococo en 17,6% de los pacientes, los principales motivos para el no cumplimiento del esquema de vacunación estuvieron en relación con el desconocimiento y a la recomendación por parte de los médicos de no hacerlo. Conclusiones: El cumplimiento de los esquemas de vacunación recomendados en la población estudiada es más bajo que los reportados en otras poblaciones. Las intervenciones más importantes para mejorar la cobertura deben ir encaminadas a la educación tanto de pacientes, como de personal médico.(AU)

Background: Vaccination against pathogens such as influenza or pneumococcus is widely recommended for patients with rheumatoid arthritis; the prevalence of adherence to these vaccination programmes in Mexico is not known. Methods: A cross-sectional descriptive study was carried out, through the application of a survey to adult patients with a diagnosis of rheumatoid arthritis treated in a tertiary hospital in Mexico City. Results: 227 patients were included, vaccination against influenza was found in 31.3% and against pneumococcus in 17.6% of patients, the main reasons for non-compliance with the vaccination schedule were related to ignorance and the recommendation by doctors not to do so. Conclusions: Compliance with the recommended vaccination schedules in the studied population is lower than those reported in other populations. The most important interventions to improve coverage should be aimed at educating both patients and medical personnel.(AU)

Antigenic Characterization of Human Monoclonal Antibodies for Therapeutic Use against H7N9 Avian Influenza Virus.

Since 2013, H7N9 avian influenza viruses (AIVs) have caused more than 1,500 human infections and the culling of millions of poultry. Despite large-scale poultry vaccination, H7N9 AIVs continue to circulate among poultry in China and pose a threat to human health. Previously, we isolated and generated four monoclonal antibodies (mAbs) derived from humans naturally infected with H7N9 AIV. Here, we investigated the hemagglutinin (HA) epitopes of H7N9 AIV targeted by these mAbs (L3A-44, K9B-122, L4A-14, and L4B-18) using immune escape studies. Our results revealed four key antigenic epitopes at HA amino acid positions 125, 133, 149, and 217. The mutant H7N9 viruses representing escape mutations containing an alanine-to-threonine substitution at residue 125 (A125T), a glycine-to-glutamic acid substitution at residue 133 (G133E), an asparagine-to-aspartic acid substitution at residue 149 (N149D), or a leucine-to-glutamine substitution at residue 217 (L217Q) showed reduced or completely abolished cross-reactivity with the mAbs, as measured by a hemagglutination inhibition (HI) assay. We further assessed the potential risk of these mutants to humans should they emerge following mAb treatment by measuring the impact of these HA mutations on virus fitness and evasion of host adaptive immunity. Here, we showed that the L4A-14 mAb had broad neutralizing capabilities, and its escape mutant N149D had reduced viral stability and human receptor binding and could be neutralized by both postinfection and antigen-induced sera. Therefore, the L4A-14 mAb could be a therapeutic candidate for H7N9 AIV infection in humans and warrants further investigation for therapeutic applications. IMPORTANCE Avian influenza virus (AIV) H7N9 continues to circulate and evolve in birds, posing a credible threat to humans. Antiviral drugs have proven useful for the treatment of severe influenza infections in humans; however, concerns have been raised as antiviral-resistant mutants have emerged. Monoclonal antibodies (mAbs) have been studied for both prophylactic and therapeutic applications in infectious disease control and have demonstrated great potential. For example, mAb treatment has significantly reduced the risk of people developing severe disease with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition to the protection efficiency, we should also consider the potential risk of the escape mutants generated by mAb treatment to public health by assessing their viral fitness and potential to compromise host adaptive immunity. Considering these parameters, we assessed four human mAbs derived from humans naturally infected with H7N9 AIV and showed that the mAb L4A-14 displayed potential as a therapeutic candidate.

Adaptación y validación de la escala MoVac-flu sobre motivación hacia la vacuna de la gripe / Adaptation and validation of the MoVac-flu scale on motivation towards the flu vaccine

Objetivo: Realizar una traducción, adaptación y validación de las propiedades psicométricas de la escala MoVac-flu para ser utilizada en español. Método: Estudio observacional analítico de adaptación transcultural y validación al español de la escala MoVac-flu. Se llevó a cabo entre los meses de marzo y julio del año 2022. El tamaño muestral fue de 142 personas que se reclutaron mediante muestreo consecutivo. Los procesos utilizados para la adaptación fueron traducción, validación por comité de expertos, retrotraducción y prueba piloto. Para la validación se comprobaron las propiedades psicométricas de fiabilidad, consistencia interna, validez de apariencia, validez de contenido, utilidad y efecto techo-suelo. Resultados. La consistencia interna de la escala MoVac-flu en su versión traducida al español fue alta, con una ω de McDonald de 0,914. Conclusiones: La escala MoVac-flu en español permite medir el grado de motivación ante la vacunación frente a la gripe de la población adulta.(AU)

Objective: To translate, adapt and validate the psychometric properties of MoVac-flu scale in order to be used in Spanish. Method: The present research was an analytical observational study of cross-cultural adaptation and validation into Spanish of the MoVac-flu scale. It has been carried out between the months of March and July 2022. The sample size was 142 people who were obtained by consecutive sampling. The processes used for the adaptation have been translation, validation by a committee of experts, back-translation and pilot test. For validation, the psychometric properties of reliability, internal consistency, appearance validity, content validity, utility and ceiling-floor effect have been verified. Results: The internal consistency of the MoVac-flu scale in its version translated into Spanish was high, showing a McDonald's ω of 0.914. Conclusions: The MoVac-flu scale in Spanish allows to measure the degree of motivation towards vaccination against influenza in the adult population.(AU)

Antibodies targeting the neuraminidase active site inhibit influenza H3N2 viruses with an S245N glycosylation site.

Contemporary influenza A H3N2 viruses circulating since 2016 have acquired a glycosylation site in the neuraminidase in close proximity to the enzymatic active site. Here, we investigate if this S245N glycosylation site, as a result of antigenic evolution, can impact binding and function of human monoclonal antibodies that target the conserved active site. While we find that a reduction in the inhibitory ability of neuraminidase active site binders is measurable, this class of broadly reactive monoclonal antibodies maintains protective efficacy in vivo.

The E3 ligase subunit FBXO45 binds the interferon-λ receptor and promotes its degradation during influenza virus infection.

Influenza remains a major public health challenge, as the viral infection activates multiple biological networks linked to altered host innate immunity. Following infection, IFN-λ, a ligand crucial for the resolution of viral infections, is known to bind to its cognate receptor, IFNLR1, in lung epithelia. However, little is known regarding the molecular expression and regulation of IFNLR1. Here, we show that IFNLR1 is a labile protein in human airway epithelia that is rapidly degraded after influenza infection. Using an unbiased proximal ligation biotin screen, we first identified that the Skp-Cullin-F box E3 ligase subunit, FBXO45, binds to IFNLR1. We demonstrate that FBXO45, induced in response to influenza infection, mediates IFNLR1 protein polyubiquitination and degradation through the ubiquitin-proteasome system by docking with its intracellular receptor domain. Furthermore, we found ectopically expressed FBXO45 and its silencing in cells differentially regulated both IFNLR1 protein stability and interferon-stimulated gene expression. Mutagenesis studies also indicated that expression of a K319R/K320R IFNLR1 variant in cells exhibited reduced polyubiquitination, yet greater stability and proteolytic resistance to FBXO45 and influenza-mediated receptor degradation. These results indicate that the IFN-λ-IFNLR1 receptor axis is tightly regulated by the Skp-Cullin-F box ubiquitin machinery, a pathway that may be exploited by influenza infection as a means to limit antiviral responses.

Insights into pandemic respiratory viruses: manipulation of the antiviral interferon response by SARS-CoV-2 and influenza A virus.

The outbreak of the COVID-19 pandemic one year after the centennial of the 1918 influenza pandemic reaffirms the catastrophic impact respiratory viruses can have on global health and economy. A key feature of SARS-CoV-2 and influenza A viruses (IAV) is their remarkable ability to suppress or dysregulate human immune responses. Here, we summarize the growing knowledge about the interplay of SARS-CoV-2 and antiviral innate immunity, with an emphasis on the regulation of type-I or -III interferon responses that are critically implicated in COVID-19 pathogenesis. Furthermore, we draw parallels to IAV infection and discuss shared innate immune sensing mechanisms and the respective viral countermeasures.

Axin1: A novel scaffold protein joins the antiviral network of interferon.

Acute respiratory infection by influenza virus is a persistent and pervasive public health problem. Antiviral innate immunity initiated by type I interferon (IFN) is the first responder to pathogen invasion and provides the first line of defense. We discovered that Axin1, a scaffold protein, was reduced during influenza virus infection. We also found that overexpression of Axin1 and the chemical stabilizer of Axin1, XAV939, reduced influenza virus replication in lung epithelial cells. This effect was also observed with respiratory syncytial virus and vesicular stomatitis virus. Axin1 boosted type I IFN response to influenza virus infection and activated JNK/c-Jun and Smad3 signaling. XAV939 protected mice from influenza virus infection. Thus, our studies provide new mechanistic insights into the regulation of the type I IFN response and present a new potential therapeutic of targeting Axin1 against influenza virus infection.

[Phylogenetic and pathogenicity analysis of influenza B virus strain B/Guangxi-Jiangzhou/1352/2018].

Influenza B virus (IBV) is more likely to cause complications than influenza A virus (IAV) and even causes higher disease burden than IAV in a certain season, but IBV has received less attention. In order to analyze the genetic evolution characteristics of the clinical strain IBV (B/Guangxi-Jiangzhou/1352/2018), we constructed genetic evolution trees and analyzed the homology and different amino acids of hemagglutinin and neuraminidase referring to the vaccine strains recommended by World Health Organization (WHO). We found that strain B/Guangxi-Jiangzhou/1352/2018 was free of interlineage reassortment and poorly matched with the vaccine strain B/Colorado/06/2017 of the same year. We also determined the median lethal dose (LD50) and the pathogenicity of strain B/Guangxi-Jiangzhou/1352/2018 in mice. The results showed that the LD50 was 105.9 TCID50 (median tissue culture infective dose), the IBV titer in the lungs reached peak 1 d post infection and the mRNA level of the most of inflammatory cytokines in the lungs reached peak 12 h post infection. The alveoli in the lungs were severely damaged and a large number of inflammatory cells were infiltrated post infection. The study demonstrated that the clinical strain IBV (B/Guangxi-Jiangzhou/1352/2018) could infect mice and induce typical lung inflammation. This will facilitate the research on the pathogenesis and transmission mechanism of IBV, and provide an ideal animal model for evaluation of new vaccines, antiviral and anti-inflammatory drug.