Antigenic drift in type A influenza virus: Peptide mapping and antigenic analysis of A/PR/8/34 (HON1) variants selected with monoclonal antibodies

Influenza virus infection causes significant morbidity and mortality worldwide. Humans fail to make a universally protective memory immune response to influenza A. Hemagglutinin and Neuraminidase undergo antigenic drift and shift, resulting in new influenza A strains to which humans are naive. Seasonal vaccines are often ineffective and escape mutants have been reported to all treatments for influenza A. In the absence of a universal influenza A vaccine or treatment, influenza A will remain a significant threat to human health. The extracellular domain of the M2-ion channel (M2e) is an ideal antigenic target for a universal therapeutic agent, as it is highly conserved across influenza A serotypes, has a low mutation rate, and is essential for viral entry and replication. Previous M2e-specific monoclonal antibodies (M2e-MAbs) show protective potential against influenza A, however, they are either strain specific or have limited efficacy. We generated seven murine M2e-MAbs and utilized in vitro and in vivo assays to validate the specificity of our novel M2e-MAbs and to explore the universality of their protective potential. Our data shows our M2e-MAbs bind to M2e peptide, HEK cells expressing the M2 channel, as well as, influenza virions and MDCK-ATL cells infected with influenza viruses of multiple serotypes. Our antibodies significantly protect highly influenza A virus susceptible BALB/c mice from lethal challenge with H1N1 A/PR/8/34, pH1N1 A/CA/07/2009, H5N1 A/Vietnam/1203/2004, and H7N9 A/Anhui/1/2013 by improving survival rates and weight loss. Based on these results, at least four of our seven M2e-MAbs show strong potential as universal influenza A treatments. IMPORTANCE Despite a seasonal vaccine and multiple therapeutic treatments, Influenza A remains a significant threat to human health. The biggest obstacle is producing a vaccine or treatment for influenza A is their universality or efficacy against not only seasonal variances in the influenza virus, but also against all human, avian, and swine serotypes and, therefore, potential pandemic strains. M2e has huge potential as a target for a vaccine or treatment against influenza A. It is the most conserved external protein on the virus. Antibodies against M2e have made it to clinical trials, but not succeeded. Here, we describe novel M2e antibodies produced in mice that are not only protective at low doses, but that we extensively test to determine their universality and found to be cross protective against all strains tested. Additionally, our work begins to elucidate the critical role of isotype for an influenza A monoclonal antibody therapeutic.

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Characteristics of Avian Influenza H9N2 Virus Isolated from Humans and its Seroprevalence Among Occupationally Exposed Populations in China

10.21203/rs.3.rs-568946/v1 ◽

2021 ◽

Author(s):

Jie Dong ◽

Hong Bo ◽

Libo Dong ◽

Ye Zhang ◽

Weijuan Huang ◽

...

Keyword(s):

Influenza Virus ◽

Receptor Binding ◽

H9n2 Virus ◽

Antigenic Drift ◽

Antigenic Analysis ◽

H9n2 Influenza Virus ◽

Binding Preference ◽

Significant Difference ◽

Occupationally Exposed ◽

Human Infections

Abstract Background: The first human-infected H9N2 influenza case can be traced back to 1998. Although the H9N2 influenza virus has low pathogenicity in animals, it donated partial or whole cassettes of internal genes to reassort novel viruses, such as H7N9, H10N8 and H5N6 viruses, that caused human infections with high fatality. Since 2013, sporadic but increasingly frequent human cases caused by H9N2 influenza virus have been confirmed globally, and most of them were from China. Methods: Information on human infections with H9N2 influenza virus was collected. Viral molecular determinants were determined by deep sequencing, and phylogenetic analysis was performed using MEGA 6.06. Antigenic analysis was performed by a hemagglutination inhibition (HI) assay. Receptor binding preference analysis was conducted based on a solid-phase binding assay with synthetic sialylglycopolymers. Antiviral susceptibility was determined by a fluorescence-based neuraminidase (NA) inhibition assay. Serological study of occupationally exposed populations was performed by HI assay screening and confirmed by microneutralization assay.Results: From 2013 to 2018, 33 human H9N2cases were reported in China, among them 75.7% were children under 10 years old .The 22 viruses were isolated and concentrated in the Y280/G9 lineage of the HA and NA genes. All human H9N2 viruses belonged to the Y280/G9 antigenic lineage, presented a human-like receptor binding preference and remained susceptible to NA inhibitors, but most demonstrated resistance to M2 inhibitors. The seroprevalence of occupationally exposed populations was 2.15%, 3.17%, 2.93% and 1.54% from 2015 to 2018, respectively. A significant difference in seroprevalence was shown between provinces with human cases (3.66%) and provinces without human cases (2.18%). Conclusions: The continuous antigenic drift and human-like receptor binding preference of the H9N2 virus enable it to have a high risk of causing human infections. The status of the seropositivity in occupationally exposed populations implies a substantial threat to public health. Research on human infection with H9N2 influenza virus should be strengthened to monitor the emergence of sustainable human-to-human transmission and the possibility of an endemic or a pandemic related to it.

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Effect of Vaccine Use in the Evolution of Mexican Lineage H5N2 Avian Influenza Virus

Journal of Virology ◽

10.1128/jvi.78.15.8372-8381.2004 ◽

2004 ◽

Vol 78 (15) ◽

pp. 8372-8381 ◽

Cited By ~ 252

Author(s):

Chang-Won Lee ◽

Dennis A. Senne ◽

David L. Suarez

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Herd Immunity ◽

Type A ◽

Antigenic Drift ◽

Highly Pathogenic ◽

Virus Shedding ◽

First Case ◽

Pathogenic Virus

ABSTRACT An outbreak of avian influenza (AI) caused by a low-pathogenic H5N2 type A influenza virus began in Mexico in 1993 and several highly pathogenic strains of the virus emerged in 1994-1995. The highly pathogenic virus has not been reported since 1996, but the low-pathogenic virus remains endemic in Mexico and has spread to two adjacent countries, Guatemala and El Salvador. Measures implemented to control the outbreak and eradicate the virus in Mexico have included a widespread vaccination program in effect since 1995. Because this is the first case of long-term use of AI vaccines in poultry, the Mexican lineage virus presented us with a unique opportunity to examine the evolution of type A influenza virus circulating in poultry populations where there was elevated herd immunity due to maternal and active immunity. We analyzed the coding sequence of the HA1 subunit and the NS gene of 52 Mexican lineage viruses that were isolated between 1993 and 2002. Phylogenetic analysis indicated the presence of multiple sublineages of Mexican lineage isolates at the time vaccine was introduced. Further, most of the viruses isolated after the introduction of vaccine belonged to sublineages separate from the vaccine's sublineage. Serologic analysis using hemagglutination inhibition and virus neutralization tests showed major antigenic differences among isolates belonging to the different sublineages. Vaccine protection studies further confirmed the in vitro serologic results indicating that commercial vaccine was not able to prevent virus shedding when chickens were challenged with antigenically different isolates. These findings indicate that multilineage antigenic drift, which has not been observed in AI virus, is occurring in the Mexican lineage AI viruses and the persistence of the virus in the field is likely aided by its large antigenic difference from the vaccine strain.

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ANTIGENIC RELATIONSHIP OF BRITISH SWINE INFLUENZA STRAINS TO STANDARD HUMAN AND SWINE INFLUENZA VIRUSES

Journal of Experimental Medicine ◽

10.1084/jem.77.5.467 ◽

1943 ◽

Vol 77 (5) ◽

pp. 467-471 ◽

Cited By ~ 10

Author(s):

N. Paul Hudson ◽

M. Michael Sigel ◽

F. S. Markham

Keyword(s):

Influenza Virus ◽

Swine Influenza ◽

Type A ◽

Influenza Viruses ◽

Antigenic Relationship ◽

Type B ◽

Antigenic Analysis ◽

Cell Agglutination ◽

Virus Inhibition ◽

Relationship Of

The antigenic relationships of Type A (PR 8, WS) and Type B (Lee) human strains and the Shope and British (Cambridge, North Ireland) swine strains were studied by specific antiserum inhibition of chicken red cell agglutination by the influenza virus. The Cambridge and North Ireland strains were found to be closely related to the Type A strains and differentiated from the Shope virus. The distinctive antigenicity of the Lee strain of Type B was confirmed. Specific antibodies were developed in chickens following single intraperitoneal injections of influenza virus. Inhibition tests yielded results, in the antigenic analysis of the influenza viruses examined, comparable to those obtained with ferret antisera. Specific inhibition of hemagglutination by influenza virus proved an effective method for the study of strain relationships.

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Antigenic drift in influenza A viruses. I. Selection and characterization of antigenic variants of A/PR/8/34 [HON1] influenza virus with monoclonal antibodies

Journal of Experimental Medicine ◽

10.1084/jem.148.2.383 ◽

1978 ◽

Vol 148 (2) ◽

pp. 383-392 ◽

Cited By ~ 103

Author(s):

W Gerhard ◽

RG Webster

Keyword(s):

Influenza Virus ◽

Monoclonal Antibodies ◽

Amino Acid ◽

Influenza A ◽

Antigenic Drift ◽

Single Amino Acid ◽

Amino Acid Substitutions ◽

Parent Virus ◽

Influenza A Viruses

Antigenic variants of A/PR/8/34 [HON1] influenza virus were selected after a single passage of the parent virus in embryonated chicken eggs in the presence of monoclonal antibodies to this virus. The monoclonal antibodies were produced by a hybridoma and were specific for an antigenic determinant on the HA molecule of the parent virus. Seven antigenic variants were analyzed with 95 monoclonal anti-HA antibodies prepared in vitro in the splenic fragment culture system. Three subgroups of antigenic variants were distinguished. The antigenic changes were primarily recognized by monoclonal antibodies to the strain- specific determinants of the parental hemagglutinin (HA) molecule. Monoclonal antibodies to HA determinants shared (in an identical or cross-reactive form) by parental virus and more than three heterologous viruses of the HON1 and H1N1 subtypes were unable to recognize the antigenic change on the variants. Similarly, heterogeneous antibody preparations could not differentiate between parental and variant viruses. The results are compatible with the idea that the HA of PR8 has available a large repertoire of antigenic modifications that may result from single amino acid substitutions, and that antigenic changes can occur in the strain- specific determinants on the HA molecule in the absence of concomitant changes in the cross-reactive HA determinants. The findings suggest that antigenic drift, in order to be epidemiologically significant, probably requires a series of amino acid substitutions in, or close to, the antigenic area on the HA molecule.

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