scholarly journals New aspects of influenza viruses.

1992 ◽  
Vol 5 (1) ◽  
pp. 74-92 ◽  
Author(s):  
M W Shaw ◽  
N H Arden ◽  
H F Maassab
Keyword(s):  
Influenza Virus ◽  
Antigenic Variation ◽  
Antiviral Agents ◽  
Molecular Techniques ◽  
Influenza Viruses ◽  
Virus Infections ◽  
Promising Alternative ◽  
Live Attenuated Influenza Virus ◽  
Virus Strains ◽  
Substantial Morbidity

Influenza virus infections continue to cause substantial morbidity and mortality with a worldwide social and economic impact. The past five years have seen dramatic advances in our understanding of viral replication, evolution, and antigenic variation. Genetic analyses have clarified relationships between human and animal influenza virus strains, demonstrating the potential for the appearance of new pandemic reassortants as hemagglutinin and neuraminidase genes are exchanged in an intermediate host. Clinical trials of candidate live attenuated influenza virus vaccines have shown the cold-adapted reassortants to be a promising alternative to the currently available inactivated virus preparations. Modern molecular techniques have allowed serious consideration of new approaches to the development of antiviral agents and vaccines as the functions of the viral genes and proteins are further elucidated. The development of techniques whereby the genes of influenza viruses can be specifically altered to investigate those functions will undoubtedly accelerate the pace at which our knowledge expands.

scholarly journals Ethanol Extract of Caesalpinia decapetala Inhibits Influenza Virus Infection In Vitro and In Vivo

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 557 ◽  
Author(s):  
Li Zhang ◽  
Jungang Chen ◽  
Chang Ke ◽  
Haiwei Zhang ◽  
Shoujun Zhang ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Antiviral Agents ◽  
Influenza Virus Infection ◽  
Virus Titer ◽  
Ethanol Extract ◽  
Influenza Viruses ◽  
Virus Infections

Influenza virus infections can lead to viral pneumonia and acute respiratory distress syndrome in severe cases, causing significant morbidity and mortality and posing a great threat to human health. Because of the diversity of influenza virus strains and drug resistance to the current direct antiviral agents, there have been no effective drugs as yet to cure all patients infected by influenza viruses. Natural products from plants contain compounds with diverse structures that have the potential to interact with multiple host and virus factors. In this study, we identified the ethanol extract of Caesalpinia decapetala (Roth) Alston (EEC) as an inhibitor against the replication of a panel of influenza A and B viruses both on human pulmonary epithelial A549 and human monocytic U937 cells. The animal study revealed that EEC administration reduces the weight loss and improves the survival rate of mice infected with lethal influenza virus. Also, EEC treatment attenuated lung injury and reduced virus titer significantly. In conclusion, we showed that EEC has antiviral activity both in vitro and in vivo, suggesting that the plant C. decapetala has the potential to be further developed as a resource of new anti-influenza drugs.

scholarly journals Next generation methodology for updating HA vaccines against emerging human seasonal influenza A(H3N2) viruses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James D. Allen ◽  
Ted M. Ross
Keyword(s):  
Influenza Virus ◽  
Immune Responses ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Viruses ◽  
Next Generation ◽  
Virus Infections ◽  
Wild Type ◽  
Influenza Hemagglutinin ◽  
H3n2 Influenza

AbstractWhile vaccines remain the best tool for preventing influenza virus infections, they have demonstrated low to moderate effectiveness in recent years. Seasonal influenza vaccines typically consist of wild-type influenza A and B viruses that are limited in their ability to elicit protective immune responses against co-circulating influenza virus variant strains. Improved influenza virus vaccines need to elicit protective immune responses against multiple influenza virus drift variants within each season. Broadly reactive vaccine candidates potentially provide a solution to this problem, but their efficacy may begin to wane as influenza viruses naturally mutate through processes that mediates drift. Thus, it is necessary to develop a method that commercial vaccine manufacturers can use to update broadly reactive vaccine antigens to better protect against future and currently circulating viral variants. Building upon the COBRA technology, nine next-generation H3N2 influenza hemagglutinin (HA) vaccines were designed using a next generation algorithm and design methodology. These next-generation broadly reactive COBRA H3 HA vaccines were superior to wild-type HA vaccines at eliciting antibodies with high HAI activity against a panel of historical and co-circulating H3N2 influenza viruses isolated over the last 15 years, as well as the ability to neutralize future emerging H3N2 isolates.

scholarly journals Sequential Seasonal H1N1 Influenza Virus Infections Protect Ferrets against Novel 2009 H1N1 Influenza Virus

2012 ◽  
Vol 87 (3) ◽  
pp. 1400-1410 ◽  
Author(s):  
Donald M. Carter ◽  
Chalise E. Bloom ◽  
Eduardo J. M. Nascimento ◽  
Ernesto T. A. Marques ◽  
Jodi K. Craigo ◽  
...  
Keyword(s):  
Influenza Virus ◽  
H1n1 Influenza ◽  
Cross Reactivity ◽  
Influenza Viruses ◽  
The Novel ◽  
Virus Infections ◽  
H1n1 Influenza Virus ◽  
Virus Shedding ◽  
2009 H1n1 ◽  
Novel H1n1 Influenza

ABSTRACTIndividuals <60 years of age had the lowest incidence of infection, with ∼25% of these people having preexisting, cross-reactive antibodies to novel 2009 H1N1 influenza. Many people >60 years old also had preexisting antibodies to novel H1N1. These observations are puzzling because the seasonal H1N1 viruses circulating during the last 60 years were not antigenically similar to novel H1N1. We therefore hypothesized that a sequence of exposures to antigenically different seasonal H1N1 viruses can elicit an antibody response that protects against novel 2009 H1N1. Ferrets were preinfected with seasonal H1N1 viruses and assessed for cross-reactive antibodies to novel H1N1. Serum from infected ferrets was assayed for cross-reactivity to both seasonal and novel 2009 H1N1 strains. These results were compared to those of ferrets that were sequentially infected with H1N1 viruses isolated prior to 1957 or more-recently isolated viruses. Following seroconversion, ferrets were challenged with novel H1N1 influenza virus and assessed for viral titers in the nasal wash, morbidity, and mortality. There was no hemagglutination inhibition (HAI) cross-reactivity in ferrets infected with any single seasonal H1N1 influenza viruses, with limited protection to challenge. However, sequential H1N1 influenza infections reduced the incidence of disease and elicited cross-reactive antibodies to novel H1N1 isolates. The amount and duration of virus shedding and the frequency of transmission following novel H1N1 challenge were reduced. Exposure to multiple seasonal H1N1 influenza viruses, and not to any single H1N1 influenza virus, elicits a breadth of antibodies that neutralize novel H1N1 even though the host was never exposed to the novel H1N1 influenza viruses.

Inhibition of ciliary activity in organ cultures of ferret trachea in reference to genetic and biological characters of influenza virus strains

1982 ◽  
Vol 28 (7) ◽  
pp. 809-814 ◽  
Author(s):  
P. Diaz-Rodriguez ◽  
A. Boudreault
Keyword(s):  
Influenza Virus ◽  
Influenza Viruses ◽  
Influenza Vaccines ◽  
Ciliary Activity ◽  
Organ Cultures ◽  
Preliminary Screening ◽  
Cold Adapted ◽  
Activity Inhibition ◽  
Biological Characters ◽  
Virus Strains

As reported previously, attenuated stable inhibitor-resistant influenza viruses can be screened by a 50% ciliary activity inhibition test in ferret tracheal organ cultures. This test was further applied to 5 attenuated cold-adapted influenza strains and to 11 strains with known a percentage of RNA–RNA hybridization with the parental A/PR/8/34 (H0N1) virus strain. Again, with one exception, attenuated strains could be clearly differentiated from virulent ones. It was concluded that virulence of influenza strains for man can be detected using this test regardless of the techniques used to prepare attenuated variants. A preliminary screening of attenuated candidates for live influenza vaccines can be achieved with confidence on ferret tracheal organ cultures.

scholarly journals Historical H1N1 Influenza Virus Imprinting Increases Vaccine Protection by Influencing the Activity and Sustained Production of Antibodies Elicited at Vaccination in Ferrets

Vaccines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 133 ◽  
Author(s):  
Magen E. Francis ◽  
Mara McNeil ◽  
Nicholas J. Dawe ◽  
Mary K. Foley ◽  
Morgan L. King ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Immune Responses ◽  
Time Course ◽  
Recovery Period ◽  
Haemagglutination Inhibition ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Immune Memory ◽  
Sublethal Dose ◽  
Virus Infections

Influenza virus imprinting is now understood to significantly influence the immune responses and clinical outcome of influenza virus infections that occur later in life. Due to the yearly cycling of influenza viruses, humans are imprinted with the circulating virus of their birth year and subsequently build a complex influenza virus immune history. Despite this knowledge, little is known about how the imprinting strain influences vaccine responses. To investigate the immune responses of the imprinted host to split-virion vaccination, we imprinted ferrets with a sublethal dose of the historical seasonal H1N1 strain A/USSR/90/1977. After a +60-day recovery period to build immune memory, ferrets were immunized and then challenged on Day 123. Antibody specificity and recall were investigated throughout the time course. At challenge, the imprinted vaccinated ferrets did not experience significant disease, while naïve-vaccinated ferrets had significant weight loss. Haemagglutination inhibition assays showed that imprinted ferrets had a more robust antibody response post vaccination and increased virus neutralization activity. Imprinted-vaccinated animals had increased virus-specific IgG antibodies compared to the other experimental groups, suggesting B-cell maturity and plasticity at vaccination. These results should be considered when designing the next generation of influenza vaccines.

Association of Severe Influenza Virus Infections With CD226 (DNAM-1) Variants

2019 ◽  
Vol 220 (7) ◽  
pp. 1162-1165 ◽  
Author(s):  
Monika Redlberger-Fritz ◽  
Hannes Vietzen ◽  
Elisabeth Puchhammer-Stöckl
Keyword(s):  
Influenza Virus ◽  
Intensive Care ◽  
Cell Response ◽  
Nk Cell ◽  
Virus Disease ◽  
Cell Receptor ◽  
Influenza Viruses ◽  
Virus Infections ◽  
Severe Influenza ◽  
Nk Cell Receptor

Abstract Natural killer (NK)-cell response against influenza viruses partly depends on expression of CD112, a ligand for NK-cell receptor CD226 (DNAM-1). We analyzed whether particular CD226 variants were associated with influenza disease severity. Comparison between 145 patients hospitalized with severe influenza at intensive care units (ICU) with 139 matched influenza-positive outpatients showed that presence of the rs763362 G allele (GG, AG) was associated with occurrence of severe influenza infections (P = .0076). Also, a higher frequency of rs727088 G and rs763361 T alleles was observed in the ICU group. Thus, CD226 variants may contribute to the severity of influenza virus disease.

scholarly journals Increasing the breadth and potency of response to the seasonal influenza virus vaccine by immune complex immunization

2017 ◽  
Vol 114 (38) ◽  
pp. 10172-10177 ◽  
Author(s):  
Jad Maamary ◽  
Taia T. Wang ◽  
Gene S. Tan ◽  
Peter Palese ◽  
Jeffrey V. Ravetch
Keyword(s):  
Influenza Virus ◽  
Virus Vaccine ◽  
Seasonal Influenza ◽  
Influenza Virus Vaccine ◽  
Virus Infections ◽  
Flu Vaccine ◽  
Main Barrier ◽  
Divergent Virus ◽  
Virus Strains

The main barrier to reduction of morbidity caused by influenza is the absence of a vaccine that elicits broad protection against different virus strains. Studies in preclinical models of influenza virus infections have shown that antibodies alone are sufficient to provide broad protection against divergent virus strains in vivo. Here, we address the challenge of identifying an immunogen that can elicit potent, broadly protective, antiinfluenza antibodies by demonstrating that immune complexes composed of sialylated antihemagglutinin antibodies and seasonal inactivated flu vaccine (TIV) can elicit broadly protective antihemagglutinin antibodies. Further, we found that an Fc-modified, bispecific monoclonal antibody against conserved epitopes of the hemagglutinin can be combined with TIV to elicit broad protection, thus setting the stage for a universal influenza virus vaccine.

scholarly journals Influenza A Virus Vaccination: Immunity, Protection, and Recent Advances Toward A Universal Vaccine

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 434 ◽  
Author(s):  
Christopher E. Lopez ◽  
Kevin L. Legge
Keyword(s):  
Immune Response ◽  
Influenza Virus ◽  
Virus Infection ◽  
Influenza A ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Antigenic Drift ◽  
Influenza Vaccines ◽  
Virus Infections ◽  
Universal Vaccine

Influenza virus infections represent a serious public health threat and account for significant morbidity and mortality worldwide due to seasonal epidemics and periodic pandemics. Despite being an important countermeasure to combat influenza virus and being highly efficacious when matched to circulating influenza viruses, current preventative strategies of vaccination against influenza virus often provide incomplete protection due the continuous antigenic drift/shift of circulating strains of influenza virus. Prevention and control of influenza virus infection with vaccines is dependent on the host immune response induced by vaccination and the various vaccine platforms induce different components of the local and systemic immune response. This review focuses on the immune basis of current (inactivated influenza vaccines (IIV) and live attenuated influenza vaccines (LAIV)) as well as novel vaccine platforms against influenza virus. Particular emphasis will be placed on how each platform induces cross-protection against heterologous influenza viruses, as well as how this immunity compares to and contrasts from the “gold standard” of immunity generated by natural influenza virus infection.

scholarly journals Immunization with Live Attenuated Influenza Viruses That Express Altered NS1 Proteins Results in Potent and Protective Memory CD8+ T-Cell Responses

2009 ◽  
Vol 84 (4) ◽  
pp. 1847-1855 ◽  
Author(s):  
Scott N. Mueller ◽  
William A. Langley ◽  
Elena Carnero ◽  
Adolfo García-Sastre ◽  
Rafi Ahmed
Keyword(s):  
Influenza Virus ◽  
T Cell ◽  
B Cell ◽  
Protective Immunity ◽  
T Cell Responses ◽  
Influenza Viruses ◽  
Wild Type Virus ◽  
Virus Infections ◽  
Cell Responses ◽  
B Cell Responses

ABSTRACT The generation of vaccines that induce long-lived protective immunity against influenza virus infections remains a challenging goal. Ideally, vaccines should elicit effective humoral and cellular immunity to protect an individual from infection or disease. Cross-reactive T- and B-cell responses that are elicited by live virus infections may provide such broad protection. Optimal induction of T-cell responses involves the action of type I interferons (IFN-I). Influenza virus expressed nonstructural protein 1 (NS1) functions as an inhibitor of IFN-I and promotes viral growth. We wanted to examine the priming of CD8+ T-cell responses to influenza virus in the absence of this inhibition of IFN-I production. We generated recombinant mouse-adapted influenza A/PR/8/34 viruses with NS1 truncations and/or deletions that also express the gp33-41 epitope from lymphocytic choriomeningitis virus. Intranasal infection of mice with the attenuated viruses primed long-lived T- and B-cell responses despite significantly reduced viral replication in the lungs compared to wild-type virus. Antigen-specific CD8+ T cells expanded upon rechallenge and generated increased protective memory T-cell populations after boosting. These results show that live attenuated influenza viruses expressing truncated NS1 proteins can prime protective immunity and may have implications for the design of novel modified live influenza virus vaccines.

scholarly journals Immunomic Analysis of the Repertoire of T-Cell Specificities for Influenza A Virus in Humans

2008 ◽  
Vol 82 (24) ◽  
pp. 12241-12251 ◽  
Author(s):  
Erika Assarsson ◽  
Huynh-Hoa Bui ◽  
John Sidney ◽  
Qing Zhang ◽  
Jean Glenn ◽  
...  
Keyword(s):  
Influenza Virus ◽  
T Cell ◽  
Influenza A Virus ◽  
Influenza A ◽  
T Cell Responses ◽  
Class Ii ◽  
Influenza Viruses ◽  
Class I ◽  
Cell Responses ◽  
Virus Strains

ABSTRACT Continuing antigenic drift allows influenza viruses to escape antibody-mediated recognition, and as a consequence, the vaccine currently in use needs to be altered annually. Highly conserved epitopes recognized by effector T cells may represent an alternative approach for the generation of a more universal influenza virus vaccine. Relatively few highly conserved epitopes are currently known in humans, and relatively few epitopes have been identified from proteins other than hemagglutinin and nucleoprotein. This prompted us to perform a study aimed at identifying a set of human T-cell epitopes that would provide broad coverage against different virus strains and subtypes. To provide coverage across different ethnicities, seven different HLA supertypes were considered. More than 4,000 peptides were selected from a panel of 23 influenza A virus strains based on predicted high-affinity binding to HLA class I or class II and high conservancy levels. Peripheral blood mononuclear cells from 44 healthy human blood donors were tested for reactivity against HLA-matched peptides by using gamma interferon enzyme-linked immunospot assays. Interestingly, we found that PB1 was the major target for both CD4+ and CD8+ T-cell responses. The 54 nonredundant epitopes (38 class I and 16 class II) identified herein provided high coverage among different ethnicities, were conserved in the majority of the strains analyzed, and were consistently recognized in multiple individuals. These results enable further functional studies of T-cell responses during influenza virus infection and provide a potential base for the development of a universal influenza vaccine.

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