Generation of an international standard serum to measure influenza virus hemagglutinin stalk-reactive antibodies

Current efforts towards the development of a universal influenza virus vaccine rely on induction of effective long-term antibody responses against conserved regions of the influenza virus glycoproteins. The stalk domain of the hemagglutinin has been targeted for this purpose due to its high degree of conservation among numerous influenza subtypes and strains. Several vaccine candidates targeting this domain are in late pre-clinical or early clinical stage of development. Currently assays to measure stalk-based immunity are not standardized and no international standard is available. As various vaccine developers are generating data from pre-clinical and clinical studies, harmonization of assay read-outs will help in the comparison of experiments conducted in different laboratories and increase confidence in results. Moreover, researchers will aim to define correlates of protection for new vaccines targeting the hemagglutinin stalk domain. Joint efforts between the Krammer Laboratory at the Icahn School of Medicine at Mount Sinai and the National Institute for Biological Standards and Control (NIBSC) led to a collaborative project to generate an international standard human serum to measure hemagglutinin stalk-reactive antibodies. The WHO Expert Committee on Biological Standardization (ECBS) is currently evaluating this project for its endorsement to generate the first international standard for antibodies to the influenza virus hemagglutinin stalk domain. Please click Download on the upper right corner to see the full abstract

Combined effect of temperature and salinity on embryonic survival of Galaxias maculatus

This study aims to evaluate the effect of temperature and salinity on Galaxias maculatus embryo survival. Embryos were incubated at 5, 10 and 15 degrees C and 0, 10 and 30 psu. At 5 degrees C all salinities induced 100% mortality. Furthermore, salinity of 30, regardless temperature, caused 100% mortality. In freshwater, embryos reached 74.7 and 69.3% survival at 10 degrees C and 15 degrees C, respectively. While, at 10 psu, the larvae survivals were higher, 88.7 and 80.0% with 10 and 15 degrees C respectively. These findings suggest that there is not a temperature- salinity interaction effect on embryonic development of G. maculatus. In conclusion the embryonic development of this fish is only possible at fresh and brackish waters and it is not viable at salt water

Effect of temperature on survival of embryos of puye Galaxias maculatus (Jenyns, 1842)

We evaluated the effect of six constant temperatures on embryonic survival, embryonic period and hatching period of Galaxias maculatus from 7 to 22 degrees C under laboratory conditions. The results of embryo survival were: 90.6 +/- 2.0, 88.7 +/- 8.6, 87.7 +/- 0.7, 89.7 +/- 4.2, 70.0 +/- 5.6 and 49.5 +/- 7.4% at temperatures of 7, 10, 13, 16, 19 and 22 degrees C. Except for the temperature of 22 C, there were no significant differences between them (P 87.7%) combined with embryonic periods of less than 27 days and hatching periods less than 6.3 days were obtained. These results will optimize embryo survival and eventually rearing of the species for commercial purposes or restocking

Effect of salinity on survival of embryos of jollytail Galaxias maculatus (Jenyns, 1842)

Eight different salinity effects on embryonic survival and embryonic and hatching phase time duration of jollytail (Galaxias maculatus) were assessed. Mean survival rates were higher at salinities values of 0, 4, 8, 12, 16 and 20 with 84.9, 84.0, 85.5, 86.1, 82.6 and 75.8% respectively with no significant differences between them; in contrast to salinity of 24 was obtained by 10.4%, significantly different from other treatments. Salinity of 28 caused 100% of mortality. According to results, the embryo is unable to resist ocean salinity and its tolerance limit is between 24 and 28. The highest larval survivals at 10 days after hatching occurred in those treatments in which embryos were performed to intermediate salinities of 8, 12 and 16 with 79.3, 80.3 and 74.6% respectively, with no significant differences between them. These results demonstrate high post-hatching viability. Embryonic time period (50%) were shorter at low salinities 0, 4, 8 and 12 with 28.7, 28.0, 29.7 and 29.7 days and the largest, in the treatments of salinities of 16 and 20 with 34.0 and 34.3 days. No significant differences were found between all of them. Regarding the average hatching time periods (50%) in the treatments of salinities of 0, 4, 8, 12, 16, 20 and 24 were 5.0, 5.5, 7.5, 8.8, 13, 0, 14.3 and 15.8 days respectively, without significant differences between them

Development of a pentavalent broadly protective nucleoside-modified mRNA vaccine against influenza B viruses

Messenger RNA (mRNA) vaccines represent a new, effective vaccine platform with high capacity for rapid development. Generation of a universal influenza virus vaccine with the potential to elicit long-lasting, broadly cross-reactive immune responses is a necessity for reducing influenza-associated morbidity and mortality. Here we focus on the development of a universal influenza B virus vaccine based on the lipid nanoparticle-encapsulated nucleoside-modified mRNA (mRNA-LNP) platform. We evaluate vaccine candidates based on different target antigens that afford protection against challenge with ancestral and recent influenza B viruses from both antigenic lineages. A pentavalent vaccine combining all tested antigens protects mice from morbidity at a very low dose of 50 ng per antigen after a single vaccination. These findings support the further advancement of nucleoside-modified mRNA-LNPs expressing multiple conserved antigens as universal influenza virus vaccine candidates

Structure of a vaccine-induced, germline-encoded human antibody defines a neutralizing epitope on the SARS-CoV-2 spike N-terminal domain

Structural characterization of infection- and vaccination-elicited antibodies in complex with antigen provides insight into the evolutionary arms race between the host and the pathogen and informs rational vaccine immunogen design. We isolated a germ line-encoded monoclonal antibody (mAb) from plasmablasts activated upon mRNA vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and determined its structure in complex with the spike glycoprotein by electron cryomicroscopy (cryo-EM). We show that the mAb engages a previously uncharacterized neutralizing epitope on the spike N-terminal domain (NTD). The high-resolution structure reveals details of the intermolecular interactions and shows that the mAb inserts its heavy complementarity-determining region 3 (HCDR3) loop into a hydrophobic NTD cavity previously shown to bind a heme metabolite, biliverdin. We demonstrate direct competition with biliverdin and that, because of the conserved nature of the epitope, the mAb maintains binding to viral variants B.1.1.7 (alpha), B.1.351 (beta), B.1.617.2 (delta), and B.1.1.529 (omicron). Our study describes a novel conserved epitope on the NTD that is readily targeted by vaccine-induced antibody responses

Hybrid microchannel-solid state micropore device for fast and optical cell detection

This paper presents a methodology for cell detection and counting using a device that combines PDMS (polydimethylsiloxane) microfluidic multilayer channels with a single solid state micropore. Optimal conditions of solid-state micropore fabrication from crystalline silicon wafers are presented. Micropores of varying size can be obtained by directly etching using an etchant agent concentration of 50 wt% KOH, at varying temperatures (40, 60, 80 °C) and voltages (100, 500, 1000 mV). Scanning Electron Microscopy (SEM), and profilometry techniques have been used for the micropore characterization. In order to find optimal conditions for cell detection a COMSOL Multiphysics simulation was performed. Pressure drop, shear stress, fluid viscosities and flow rates parameters were evaluated. The potential viability of the device for cell detection and counting, avoiding cellular damage, is demonstrated.Fil: Olmos Carreno, Carol Maritza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Rosero Yánez, Gustavo Ivan. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández Cabada, Tamara. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Booth, Ross. MilliporeSigma Corporation; Estados UnidosFil: Der, Manuel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cabaleiro, Juan Martin. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Ingeniería Mecánica. Laboratorio de Fluidodinámica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Debut, Alexis. Universidad de Las Fuerzas Armadas; EcuadorFil: Cumbal Flores, Luis. Universidad de Las Fuerzas Armadas; EcuadorFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Florida International University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin