A live attenuated H5N2 prime- inactivated H5N1 boost vaccination induces influenza virus hemagglutinin stalk specific antibody responses.

A live attenuated H5N2 prime- inactivated H5N1 boost vaccination induces influenza virus hemagglutinin stalk specific antibody responses. Vaccine. 2019 Nov 07;: Authors: Kongchanagul A, Samnuan K, Wirachwong P, Surichan S, Puthavathana P, Pitisuttithum P, Boonnak K Abstract BACKGROUND: The emergence and spread of highly pathogenic avian influenza (H5N1) viruses have raised global concerns of a possible human pandemic, spurring efforts towards H5N1 influenza vaccine development and improvements in vaccine administration methods. We previously showed that a prime-boost vaccination strategy induces robust and broadly cross-reactive antibody responses against the hemagglutinin globular head domain. Here, we specifically measure antibodies against the conserved hemagglutinin stem region in serum samples obtained from the prior study to determine whether stalk-reactive antibodies can also be induced by the prime-boost regimen. METHOD: Serum samples collected from 60 participants before vaccination and on days 7, 28 and 90 following boosting vaccination were used in this study. 40 participants received two doses of live attenuated H5N2 vaccine (LAIV H5N2) followed by one dose of inactivated H5N1 vaccine a year later, while 20 participants received only the inactivated H5N1 vaccine. We tested these serum samples for stalk-reactive antibodies via enzyme-linked immunosorbent (ELISA) and microneutralization assays. RESULTS: Stalk-specific antibody levels ...
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research

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In this study, we investigated the delivery of insect cell culture-derived recombinant hemagglutinin protein (HA) of A/H5N1/Vietnam/1203/2004 virus using CaPNP. We evaluated the vaccine immunogenicity in mice following two intramuscular doses of 3 μg antigen combined with escalating doses of CaPNP. Our data showed CaPNP-adjuvanted HA(H5N1) vaccines eliciting significantly higher IgG, hemagglutination inhibition, and virus neutralization titers compared to non-adjuvanted vaccine. Among the four adjuvant doses that were tested, CaPNP at 0.24% final concentration elicited the highest IgG and neutralizing antibody tite...
Source: AAPS PharmSciTech - Category: Drugs & Pharmacology Authors: Tags: AAPS PharmSciTech Source Type: research
The highly pathogenic (HP) avian influenza virus (AIV), H5N1 and reassortant H5-subtype HPAIVs, H5N2, H5N6, and H5N8, cause high mortality in domestic birds, resulting in economic losses in the poultry industry. H5N1 and H5N6 also pose significant public health risks and H5N1 viruses are a permanent pandemic threat. To control HPAIVs, eukaryotic expression systems have traditionally been exploited to produce vaccines based on hemagglutinin (HA), a protective viral antigen. In contrast, we used a bacterial expression system to produce vaccine targeting the HA protein. A fragment of the HA ectodomain from H5N1, with a multib...
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
Abstract Avian influenza virus (AIV) is an extraordinarily diverse pathogen that causes significant morbidity in domesticated poultry populations and threatens human life with looming pandemic potential. Controlling avian influenza in susceptible populations requires highly effective, economical and broadly reactive vaccines. Several AIV vaccines have proven insufficient despite their wide use, and better technologies are needed to improve their immunogenicity and broaden effectiveness. Previously, we developed a "mosaic" H5 subtype hemagglutinin (HA) AIV vaccine and demonstrated its broad protection aga...
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
Background: A/H5N1 influenza virus has significant pandemic potential, and vaccination is the main prophylactic measure. This phase 2, randomized, observer-blind, multicenter study evaluated the safety and immunogenicity of two MF59-adjuvanted, cell culture-derived H5N1 (aH5N1c) vaccine formulations in healthy pediatric subjects 6 months to 17 years old. Methods: Subjects (N = 662) received 2 aH5N1c doses 3 weeks apart, containing either 7.5 μg (full dose) or 3.75 μg (half dose) hemagglutinin antigen per dose. Local reactions and adverse events (AEs) were assessed by age. Antibody responses were measured by hema...
Source: The Pediatric Infectious Disease Journal - Category: Infectious Diseases Tags: Vaccine Reports Source Type: research
In conclusion, we have established reverse genetics to generate a qualified reassortant H5N2 vaccine virus for further development.
Source: Viruses - Category: Virology Authors: Tags: Article Source Type: research
ConclusionsThis Phase I trial showed the MDCK-derived H5N1 candidate vaccine is safe and immunogenic. The source of RBCs has a significant impact on the measurement of HAI titers (ClinicalTrials.gov number: NCT01675284.).
Source: Journal of Microbiology, Immunology and Infection - Category: Microbiology Source Type: research
In conclusion, the reported results highlight the importance of AIV attachment to trachea in many avian species. Finally, the importance of chickens and mallards in AIVs dynamics was illustrated by the abundant AIV attachment observed. Introduction Influenza A viruses (IAVs) are pathogens of global concern in both human and veterinary medicine (Webster et al., 1992; Stöhr, 2002; Olsen et al., 2006; Wiethoelter et al., 2015). Wild birds are well-described hosts of avian influenza viruses (AIVs) and longitudinal surveillance studies have demonstrated a plethora of low pathogenic AIVs (LPAIVs) circulating in wild...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
María Maximina B. Moreno-Altamirano1*, Simon E. Kolstoe2 and Francisco Javier Sánchez-García1* 1Laboratorio de Inmunorregulación, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico 2School of Health Sciences, University of Portsmouth, Portsmouth, United Kingdom Over the last decade, there has been significant advances in the understanding of the cross-talk between metabolism and immune responses. It is now evident that immune cell effector function strongly depends on the metabolic pathway in w...
Source: Frontiers in cellular and infection microbiology - Category: Microbiology Source Type: research
Conclusions: Human challenge studies and systems biology approaches are important tools that should be used in concert to advance our understanding of influenza infection and provide targets for novel therapeutics and immunizations. Introduction Although influenza virus was recognized as an important pathogen over a century ago, influenza continues to cause a significant burden of disease. In the United States alone, it's estimated that in the 2017–2018 season there were 959,000 hospitalizations related to influenza illness, and 79,400 deaths (CDC, 2018). Worldwide, WHO estimates that annual influenza...
Source: Frontiers in cellular and infection microbiology - Category: Microbiology Source Type: research
The objective of this preclinical study was to assess the protective immunity induced by immunization with group 1 hemagglutinin-specific influenza virus vaccines based on chimeric hemagglutinins (cHAs) in a ferret model of influenza. The experimental designs and immunization strategies are summarized in Figure 1. Since most human adults have a primed repertoire of B cells with specificity to the HA stalk domain (19, 30), we included an influenza B virus expressing cH9/1 (B-cH9/1) to mimic pre-existing HA stalk immunity. We then compared the ability of our sequential immunization strategies to boost antibody titers against...
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
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