Project description:The significant economic burden and high mortality rates resulting from seasonal influenza outbreaks, especially in high risk groups such as the elderly, represent an important public health problem. The prevailing inadequate efficacy of seasonal vaccines, both conventional and elderly-tailored, is a crucial bottleneck. Consequentially, understanding immunological and molecular mechanisms resulting in differential influenza vaccine responsiveness is a prerequisite for the development of new or improved vaccination strategies. To assess differences within the specific risk group of the elderly, randomly selected individuals (≥ 65 years) were immunized with the adjuvanted influenza vaccine Fluad®. Samples were subjected to single cell transcriptome analysis. The analyses revealed profound features segregating vaccine responders from nonresponders as classified according to their vaccine-induced sero-conversion. Non-responders are characterized by a poorly functional, suppressive phenotype, showing a weaker humoral and cellular immune activation and more suppressive regulatory T and B cells. Triple responders display an efficient immune functionality characterized by the activation of humoral and cellular immunity and the up-regulation of genes related to signaling pathways, including those for anti-viral responses, protein processing and B cell activation. The generated comprehensive high dimensional dataset enables the identification of putative mechanisms and nodes responsible for vaccine non-responsiveness regardless of confounding age-dependent effects.
Project description:The significant economic burden and high mortality rates resulting from seasonal influenza outbreaks, especially in high risk groups such as the elderly, represent an important public health problem. The prevailing inadequate efficacy of seasonal vaccines, both conventional and elderly-tailored, is a crucial bottleneck. Consequentially, understanding immunological and molecular mechanisms resulting in differential influenza vaccine responsiveness is a prerequisite for the development of new or improved vaccination strategies. To assess differences within the specific risk group of the elderly, randomly selected individuals (≥ 65 years) were immunized with the adjuvanted influenza vaccine Fluad®. Samples were subjected to transcriptome analysis. The analyses revealed profound features segregating vaccine responders from nonresponders as classified according to their vaccine-induced sero-conversion. Non-responders are characterized by a poorly functional, suppressive phenotype, showing a weaker humoral and cellular immune activation and more suppressive regulatory T and B cells. Triple responders display an efficient immune functionality characterized by the activation of humoral and cellular immunity and the up-regulation of genes related to signaling pathways, including those for anti-viral responses, protein processing and B cell activation. The generated comprehensive high dimensional dataset enables the identification of putative mechanisms and nodes responsible for vaccine non-responsiveness regardless of confounding age-dependent effects.
Project description:Influenza virus vaccination remains the best strategy for combating virus infection, but vaccine efficacy is highly variable. An ideal influenza vaccine must have two attributes: one, it should be capable of inducing broadly cross-reactive antibodies that can neutralize diverse influenza virus strains; and two, it must induce long-lived antibody responses to maintain protective immunity for extended periods. Germinal center (GC) reactions are the major sites where diversification and affinity maturation of B cells occur. Whether a persistent GC response could expand the breadth of responding B cell clones following influenza vaccination in humans remains unknown. Here, we show that influenza virus vaccine-specific GC B cells persist for over nine weeks post vaccination in two out of seven individuals. These late vaccine-specific GC B cells exhibited increased somatic hypermutation (SHM) of their B cell receptors compared to early vaccine-specific GC B cells. After re-immunization with seasonal influenza virus vaccine, individuals with a persistent GC engaged vaccine-specific plasmablasts (PBs) with higher SHM frequency. Tracking the maturation of three clonally related GC B cell lineages over time revealed that late GC B cells had receptors that recognized and neutralized heterologous influenza virus strains. Thus, SHM induced by persistent GCs can broaden the antibody response to influenza virus vaccination. This indicates that seasonal influenza virus vaccination in humans can induce broadly cross-reactive antibodies that target diverse influenza virus strains.
Project description:Influenza virus vaccination remains the best strategy for combating virus infection, but vaccine efficacy is highly variable. An ideal influenza vaccine must have two attributes: one, it should be capable of inducing broadly cross-reactive antibodies that can neutralize diverse influenza virus strains; and two, it must induce long-lived antibody responses to maintain protective immunity for extended periods. Germinal center (GC) reactions are the major sites where diversification and affinity maturation of B cells occur. Whether a persistent GC response could expand the breadth of responding B cell clones following influenza vaccination in humans remains unknown. Here, we show that influenza virus vaccine-specific GC B cells persist for over nine weeks post vaccination in two out of seven individuals. These late vaccine-specific GC B cells exhibited increased somatic hypermutation (SHM) of their B cell receptors compared to early vaccine-specific GC B cells. After re-immunization with seasonal influenza virus vaccine, individuals with a persistent GC engaged vaccine-specific plasmablasts (PBs) with higher SHM frequency. Tracking the maturation of three clonally related GC B cell lineages over time revealed that late GC B cells had receptors that recognized and neutralized heterologous influenza virus strains. Thus, SHM induced by persistent GCs can broaden the antibody response to influenza virus vaccination. This indicates that seasonal influenza virus vaccination in humans can induce broadly cross-reactive antibodies that target diverse influenza virus strains.
2024-06-13 | GSE211869 | GEO
Project description:Center for Research on Influenza Pathogenesis (CRIP)
Project description:Background: Cell-based quadrivalent-inactivated influenza vaccine has been shown to have higher vaccine effectiveness than traditional egg-based quadrivalent-inactivated influenza vaccine. This is observed despite similar levels of serum hemagglutinin antibodies induced by each vaccine. Results: Cell-based influenza vaccine induced greater interferon-stimulated and innate immune gene activation compared with egg-based influenza vaccine. Participants who seroconverted had increased interferon-signaling activation versus those who did not seroconvert. Conclusions: These data suggest that cell-based influenza vaccine stimulates immune activation differently from egg-based influenza vaccine, shedding light on reported differences in vaccine effectiveness.
Project description:Influenza viruses (IV) infection is a public health concern worldwide. Currently, all available vaccines as well as antiviral drugs that target the virus itself are prone to resistance. Lessons learned from previous pandemic outbreaks is that people with a preexisting cellular immune response are either protected or developed less severe disease against the infection. Understanding CD8+ T cell immunity to IV across prominent HLA types is pivotal to rationally designing a universal influenza vaccine and generating protective immunity, especially for high-risk populations. Using mass spectroscopy, an immunopeptidomics analysis was carried out to characterize the entire landscape of peptides presented by MHC-I molecules post IV infection at different time points. We were able to identify sixteen naturally-presented MHC-I ligands restricted to different HLA allotypes including HLA-A*68, HLA-A*24, HLA-B*51, and HLA-B*07. Of these, nine peptides were immunogenic with multifunctional memory CD8 T cell response in different donors. These results highlight novel broadly protective IAV-derived CD8+ epitopes that reflect physiological peptide processing and presentation mechanisms that can work cooperatively with other distinct epitopes to provide optimal protection in particular against the newly-emerging variants.
Project description:Systems approaches have been used to describe molecular signatures driving immunity to influenza vaccination in humans. Whether such signatures are similar across multiple seasons, and in diverse populations is unknown. We applied systems approaches to study immune responses in young and, elderly subjects vaccinated with the seasonal influenza vaccine across 5 consecutive seasons.