scholarly journals Antigenic Pressure on H3N2 Influenza Virus Drift Strains Imposes Constraints on Binding to Sialylated Receptors but Not Phosphorylated Glycans

2019 ◽  
Vol 93 (22) ◽  
Author(s):  
Lauren Byrd-Leotis ◽  
Chao Gao ◽  
Nan Jia ◽  
Akul Y. Mehta ◽  
Jessica Trost ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Guinea Pig ◽  
Influenza A ◽  
Antigenic Drift ◽  
Protective Effects ◽  
Immune Pressure ◽  
Antigenic Properties ◽  
H3n2 Influenza ◽  
H3n2 Influenza Virus ◽  
Selection Of

ABSTRACT H3N2 strains of influenza A virus emerged in humans in 1968 and have continued to circulate, evolving in response to human immune pressure. During this process of “antigenic drift,” viruses have progressively lost the ability to agglutinate erythrocytes of various species and to replicate efficiently under the established conditions for amplifying clinical isolates and generating vaccine candidates. We have determined the glycome profiles of chicken and guinea pig erythrocytes to gain insights into reduced agglutination properties displayed by drifted strains and show that both chicken and guinea pig erythrocytes contain complex sialylated N-glycans but that they differ with respect to the extent of branching, core fucosylation, and the abundance of poly-N-acetyllactosamine (PL) [-3Galβ1-4GlcNAcβ1-]n structures. We also examined binding of the H3N2 viruses using three different glycan microarrays: the synthetic Consortium for Functional Glycomics array; the defined N-glycan array designed to reveal contributions to binding based on sialic acid linkage type, branched structures, and core modifications; and the human lung shotgun glycan microarray. The results demonstrate that H3N2 viruses have progressively lost their capacity to bind nearly all canonical sialylated receptors other than a selection of biantennary structures and PL structures with or without sialic acid. Significantly, all viruses displayed robust binding to nonsialylated high-mannose phosphorylated glycans, even as the recognition of sialylated structures is decreased through antigenic drift. IMPORTANCE Influenza subtype H3N2 viruses have circulated in humans for over 50 years, continuing to cause annual epidemics. Such viruses have undergone antigenic drift in response to immune pressure, reducing the protective effects of preexisting immunity to previously circulating H3N2 strains. The changes in hemagglutinin (HA) affiliated with drift have implications for the receptor binding properties of these viruses, affecting virus replication in the culture systems commonly used to generate and amplify vaccine strains. Therefore, the antigenic properties of the vaccines may not directly reflect those of the circulating strains from which they were derived, compromising vaccine efficacy. In order to reproducibly provide effective vaccines, it will be critical to understand the interrelationships between binding, antigenicity, and replication properties in different growth substrates.

scholarly journals PROBLEMS OF ISOLATION, IDENTIFICATION AND ANTIGENIC CHARACTERIZATION OF RECENT HUMAN A(H3N2) INFLUENZA VIRUSES

2018 ◽  
Vol 63 (4) ◽  
pp. 160-164
Author(s):  
P. A. Petrova ◽  
N. I. Konovalova ◽  
D. M. Danilenko ◽  
A. D. Vasilieva ◽  
M. Yu. Eropkin
Keyword(s):  
Influenza A ◽  
Influenza Viruses ◽  
High Rate ◽  
Influenza Vaccines ◽  
Antigenic Analysis ◽  
Hemagglutination Inhibition Test ◽  
Glycosylation Sites ◽  
Antigenic Properties ◽  
H3n2 Influenza ◽  
Selection Of

Human A (H3N2) influenza viruses are distinguished by a high rate of evolution and regularly cause epidemics around the world. Their ability to adapt and to escape from the host's immune response and to change their receptor specificity is very high. Over the past 20 years, these viruses have lost the ability to agglutinate red blood cells of chickens and turkeys and have practically ceased to propagate in chicken embryos - the main source of influenza vaccines. Isolation of viruses in the MDCK cell culture led to the selection of strains that lose one of the potential glycosylation sites. Many of the A (H3N2) strains have acquired mutations in neuraminidase, which distort the results of antigenic analysis in the hemagglutination inhibition test - the cornerstone method for the analysis of the match between viral isolates circulating in human population to strains selected for the influenza vaccines. In this regard, the characteristics of the antigenic properties of influenza A (H3N2) viruses by traditional methods become poorly informative, and the selection of vaccine strains of this subtype is erroneous, which is reflected in the discrepancy between vaccine and circulating A (H3N2) viruses in recent years (2013-2014, 2014 -2015, 2015-2016). The search, development and implementation of new algorithms for the isolation and antigen analysis of influenza A (H3N2) viruses are extremely urgent.

Evaluation of cytokine production by J774.G8 macrophages after treatment with biotherapics

2021 ◽  
Vol 10 (36) ◽  
pp. 167-169
Author(s):  
Camila Siqueira ◽  
Diogo Kuczera ◽  
Eneida Da Lozzo ◽  
Dorly Buchi ◽  
José Nelson Couceiro ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Viral Infection ◽  
Influenza A ◽  
Control Groups ◽  
Viral Particles ◽  
Significant Difference ◽  
Infected Cells ◽  
H3n2 Influenza ◽  
Aseptic Conditions ◽  
H3n2 Influenza Virus

Introduction: Strains of macrophages, such as murine J774.G8 macrophages, are susceptible to influenza A infection [1]. One of the responses to viral infection involves the production of various types of immunostimulatory cytokines by infected cells [2]. Methods: In the present study, the macrophage strain J774.G8, maintained in RPMI medium, was submitted to treatment with 10% V/V of two different biotherapics prepared from influenza H3N2, both at 30x. Additionally, two control groups were analyzed: macrophages stimulated with water 30x and macrophages without any treatment. Biotherapics were prepared from intact H3N2 influenza virus and H3N2 inactivated by alcohol 70%. The compounding of both biotherapics followed this procedure: one part of viral particles was diluted in 9 parts of sterile distilled water. The 1:10 sample was submitted to 100 mechanical succussions using Autic® Brazilian machine, originating the first dilution, named decimal (1x). 1 ml of this solution was diluted in 9 ml of solvent and was submitted to 100 succussions, generating biotherapic 2x. This procedure was successively repeated, according to Brazilian Homeopathic Pharmacopoeia, to obtain the biotherapic 30x. By the same technique, water vehicle was prepared in the potency of 30x to be used as control. All samples were prepared under sterile and aseptic conditions, using laminar flow cabinet, class II, and were stored in the refrigerator (8ºC), to avoid microbiological contamination. J774.G8 macrophages were stimulated for 2 days, in a total of six stimuli. Immediately before infection with 25 µl of H3N2 influenza virus, the supernatants were collected and frozen at -20 ºC for later analysis. Next, 24 hours after the virus infection, the supernatants were aliquoted and frozen under the same conditions. Three independent experiments were done in triplicate. Analysis of supernatants was performed by flow cytometry using the Mouse Inflammation Kit. The cytokines detected in this experiment were IL-10, IL 12, TNF-α and MCP1. Results: In all cases, there were no significant differences compared to control groups. However, the production of TNF-α detected in macrophages treated by intact and inactivated biotherapics presented a tendency to increase after infection. In fact, similar results were previously detected in other experiments conducted only with the intact biotherapic [3]. The release of the cytokine MCP1 in all experimental situations presented a tendency to decrease after the viral infection when compared to untreated macrophages. No statistically significant difference was detected in the production of IL 12 and IL 10. These experiments will be repeated to confirm the data obtained.

scholarly journals Divergent Human-Origin Influenza Viruses Detected in Australian Swine Populations

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Frank Y. K. Wong ◽  
Celeste Donato ◽  
Yi-Mo Deng ◽  
Don Teng ◽  
Naomi Komadina ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Antigenic Drift ◽  
Human Origin ◽  
Human Influenza ◽  
Influenza A Viruses ◽  
Data Set ◽  
Antigenic Properties

ABSTRACTGlobal swine populations infected with influenza A viruses pose a persistent pandemic risk. With the exception of a few countries, our understanding of the genetic diversity of swine influenza viruses is limited, hampering control measures and pandemic risk assessment. Here we report the genomic characteristics and evolutionary history of influenza A viruses isolated in Australia from 2012 to 2016 from two geographically isolated swine populations in the states of Queensland and Western Australia. Phylogenetic analysis with an expansive human and swine influenza virus data set comprising >40,000 sequences sampled globally revealed evidence of the pervasive introduction and long-term establishment of gene segments derived from several human influenza viruses of past seasons, including the H1N1/1977, H1N1/1995, H3N2/1968, and H3N2/2003, and the H1N1 2009 pandemic (H1N1pdm09) influenza A viruses, and a genotype that contained gene segments derived from the past three pandemics (1968, reemerged 1977, and 2009). Of the six human-derived gene lineages, only one, comprising two viruses isolated in Queensland during 2012, was closely related to swine viruses detected from other regions, indicating a previously undetected circulation of Australian swine lineages for approximately 3 to 44 years. Although the date of introduction of these lineages into Australian swine populations could not be accurately ascertained, we found evidence of sustained transmission of two lineages in swine from 2012 to 2016. The continued detection of human-origin influenza virus lineages in swine over several decades with little or unpredictable antigenic drift indicates that isolated swine populations can act as antigenic archives of human influenza viruses, raising the risk of reemergence in humans when sufficient susceptible populations arise.IMPORTANCEWe describe the evolutionary origins and antigenic properties of influenza A viruses isolated from two separate Australian swine populations from 2012 to 2016, showing that these viruses are distinct from each other and from those isolated from swine globally. Whole-genome sequencing of virus isolates revealed a high genotypic diversity that had been generated exclusively through the introduction and establishment of human influenza viruses that circulated in past seasons. We detected six reassortants with gene segments derived from human H1N1/H1N1pdm09 and various human H3N2 viruses that circulated during various periods since 1968. We also found that these swine viruses were not related to swine viruses collected elsewhere, indicating independent circulation. The detection of unique lineages and genotypes in Australia suggests that isolated swine populations that are sufficiently large can sustain influenza virus for extensive periods; we show direct evidence of a sustained transmission for at least 4 years between 2012 and 2016.

scholarly journals In Vitro Characterization of A-315675, a Highly Potent Inhibitor of A and B Strain Influenza Virus Neuraminidases and Influenza Virus Replication

2002 ◽  
Vol 46 (4) ◽  
pp. 1014-1021 ◽  
Author(s):  
Warren M. Kati ◽  
Debra Montgomery ◽  
Robert Carrick ◽  
Larisa Gubareva ◽  
Clarence Maring ◽  
...  
Keyword(s):  
Cell Culture ◽  
Influenza Virus ◽  
Virus Replication ◽  
Influenza A ◽  
Strong Support ◽  
Oseltamivir Carboxylate ◽  
Influenza Virus Replication ◽  
H3n2 Influenza ◽  
H3n2 Influenza Virus

ABSTRACT A-315675 is a novel, pyrrolidine-based compound that was evaluated in this study for its ability to inhibit A and B strain influenza virus neuraminidases in enzyme assays and influenza virus replication in cell culture. A-315675 effectively inhibited influenza A N1, N2, and N9 and B strain neuraminidases with inhibitor constant (Ki ) values between 0.024 and 0.31 nM. These values were comparable to or lower than the Ki values measured for oseltamivir carboxylate (GS4071), zanamivir, and BCX-1812, except for the N1 enzymes that were found to be the most sensitive to BCX-1812. The time-dependent inhibition of neuraminidase catalytic activity observed with A-315675 is likely due to its very low rate of dissociation from the active site of neuraminidase. The half times for dissociation of A-315675 from B/Memphis/3/89 and A/Tokyo/3/67 (H3N2) influenza virus neuraminidases of 10 to 12 h are significantly slower than the half times measured for oseltamivir carboxylate (33 to 60 min). A-315675 inhibited the replication of several laboratory strains of influenza virus in cell culture with potencies that were comparable or superior to those for oseltamivir carboxylate and BCX-1812, except for the A/H1N1 viruses that were found to be two- to fourfold more susceptible to BCX-1812. A-315675 and oseltamivir carboxylate exhibited comparable potencies against a panel of A/H1N1 and A/H3N2 influenza virus clinical isolates, but A-315675 was found to be significantly more potent than oseltamivir carboxylate against the B strain isolates. The favorable in vitro results relative to other clinically effective agents provide strong support for the further investigation of A-315675 as a potential therapy for influenza virus infections.

scholarly journals A Pyrosequencing-Based Approach to High-Throughput Identification of Influenza A(H3N2) Virus Clades Harboring Antigenic Drift Variants

2016 ◽  
Vol 55 (1) ◽  
pp. 145-154 ◽  
Author(s):  
Vasiliy P. Mishin ◽  
Tatiana Baranovich ◽  
Rebecca Garten ◽  
Anton Chesnokov ◽  
Anwar I. Abd Elal ◽  
...  
Keyword(s):  
Influenza A ◽  
Epidemiological Studies ◽  
Antigenic Drift ◽  
H3n2 Virus ◽  
Snp Analysis ◽  
Analytical Sensitivity ◽  
Close Monitoring ◽  
Antigenic Properties ◽  
Respiratory Specimens ◽  
Virological Surveillance

ABSTRACTThe rapid evolution of influenza A(H3N2) viruses necessitates close monitoring of their antigenic properties so the emergence and spread of antigenic drift variants can be rapidly identified. Changes in hemagglutinin (HA) acquired by contemporary A(H3N2) viruses hinder antigenic characterization by traditional methods, thus complicating vaccine strain selection. Sequence-based approaches have been used to infer virus antigenicity; however, they are time consuming and mid-throughput. To facilitate virological surveillance and epidemiological studies, we developed and validated a pyrosequencing approach that enables identification of six HA clades of contemporary A(H3N2) viruses. The identification scheme of viruses of the H3 clades 3C.2, 3C.2a, 3C.2b, 3C.3, 3C.3a, and 3C.3b is based on the interrogation of five single nucleotide polymorphisms (SNPs) within three neighboring HA regions, namely 412 to 431, 465 to 481, and 559 to 571. Two bioinformatics tools, IdentiFire (Qiagen) and FireComb (developed in-house), were utilized to expedite pyrosequencing data analysis. The assay's analytical sensitivity was 10 focus forming units, and respiratory specimens with threshold cycle (CT) values of <34 typically produced good quality pyrograms. When applied to 120 A(H3N2) virus isolates and 27 respiratory specimens, the assay displayed 100% agreement with clades determined by HA sequencing coupled with phylogenetics. The multi-SNP analysis described here was readily adopted by another laboratory with pyrosequencing capabilities. The implementation of this approach enhanced the findings from virological surveillance and epidemiological studies between 2013 and 2016, which examined more than 3,000 A(H3N2) viruses.

scholarly journals Structure of an H3N2 influenza virus nucleoprotein

2021 ◽  
Vol 77 (7) ◽  
Author(s):  
Michael L. Knight ◽  
Haitian Fan ◽  
David L. V. Bauer ◽  
Jonathan M. Grimes ◽  
Ervin Fodor ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Rna Binding ◽  
H3n2 Virus ◽  
Influenza A Viruses ◽  
Seasonal Epidemic ◽  
H3n2 Influenza ◽  
Structural Levels ◽  
Viral Genomic Rna ◽  
H3n2 Influenza Virus

Influenza A viruses of the H1N1 and H3N2 subtypes are responsible for seasonal epidemic events. The influenza nucleoprotein (NP) binds to the viral genomic RNA and is essential for its replication. Efforts are under way to produce therapeutics and vaccines targeting the NP. Despite this, no structure of an NP from an H3N2 virus has previously been determined. Here, the structure of the A/Northern Territory/60/1968 (H3N2) influenza virus NP is presented at 2.2 Å resolution. The structure is highly similar to those of the A/WSN/1933 (H1N1) and A/Hong Kong/483/97 (H5N1) NPs. Nonconserved amino acids are widely dispersed both at the sequence and structural levels. A movement of the 73–90 RNA-binding loop is observed to be the key difference between the structure determined here and previous structures. The data presented here increase the understanding of structural conservation amongst influenza NPs and may aid in the design of universal interventions against influenza.

scholarly journals A Mutant H3N2 Influenza Virus Uses an Alternative Activation Mechanism in TMPRSS2 Knockout Mice by Loss of an Oligosaccharide in the Hemagglutinin Stalk Region

2015 ◽  
Vol 89 (9) ◽  
pp. 5154-5158 ◽  
Author(s):  
Kouji Sakai ◽  
Tsuyoshi Sekizuka ◽  
Yasushi Ami ◽  
Noriko Nakajima ◽  
Minori Kitazawa ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Influenza A ◽  
Essential Role ◽  
Activation Mechanism ◽  
Alternative Activation ◽  
Proteolytic Activation ◽  
High Virulence ◽  
H3n2 Influenza ◽  
Ha Protein ◽  
H3n2 Influenza Virus

The host protease TMPRSS2 plays an essential role in proteolytic activation of the influenza A virus (IAV) hemagglutinin (HA) protein possessing a monobasic cleavage site. However, after passages in TMPRSS2 knockout mice, an H3N2 subtype IAV began to undergo cleavage activation of HA, showing high virulence in the mice due to the loss of an oligosaccharide at position 8 in the HA stalk region. Thus, the H3N2 IAV acquired cleavability by an alternative HA activation mechanism/protease(s).

scholarly journals Epidemic mechanisms of Type A influenza

1979 ◽  
Vol 83 (1) ◽  
pp. 11-26 ◽  
Author(s):  
R. E. Hope-simpson
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Latent Virus ◽  
Antigenic Drift ◽  
Specific Immunity ◽  
Free Interval ◽  
Serial Interval ◽  
Minor Variant ◽  
Tentative Hypothesis ◽  
H3n2 Influenza

SUMMARYThe antigenic varieties of influenza A virus isolated from 1968 to 1976 in a surveillance of a small, rather remote population were similar to those from England and Wales as a whole, despite frequent antigenic changes during the period. Household studies in the first two H3N2 influenza A epidemics found low attack rates within households, a high proportion (70%) of affected households with only one case of influenza, similar distributions of affected households in the two epidemics by the number of cases of influenza and similar distributions of the influenza cases by the day of their onset in the household outbreak. No serial interval could be demonstrated by cumulating household outbreaks. More than one minor variant was causing influenza contemporaneously in the same villages in several seasons, and different variants were on one occasion found on successive days in bedfellows. The regular occurrence of epidemics in winter was often accompanied by the disappearance of the epidemic variants and their replacement, after a virus-free interval, by new variants.These epidemiological findings seem best interpreted on the following tentative hypothesis. Influenza A sufferers do not transmit the virus during their illness; instead it rapidly becomes latent in their tissues so that they become symptomless carrier-hosts and develop specific immunity. Next season an extraneous seasonally mediated stimulus reactivates the latent virus residues so that the carrier-host becomes briefly infectious, though symptomless. Antigenic drift occurs because particles reconstituted to be identical with the progenitor virus cannot escape the specific immunity it has provoked in the carrier host. He can shed only mutants also determined by the progenitor virus. From the assortment of mutants shed by the carrier-host, his non-immune companions select that (those) which is best fitted to survive, and it rapidly causes influenzal illness. Epidemics consist largely or entirely of such persons sick with influenza caused by reactivated virus caught from symptomless carrier-hosts.

scholarly journals Evolution of H3N2 Influenza Virus in a Guinea Pig Model

PLoS ONE ◽  
2011 ◽  
Vol 6 (7) ◽  
pp. e20130 ◽  
Author(s):  
Jinxue Long ◽  
Ruth V. Bushnell ◽  
John K. Tobin ◽  
Keyao Pan ◽  
Michael W. Deem ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Guinea Pig ◽  
Pig Model ◽  
H3n2 Influenza ◽  
Guinea Pig Model ◽  
H3n2 Influenza Virus

scholarly journals Infection with influenza A/Victoria virus in Houston families, 1976

1981 ◽  
Vol 86 (3) ◽  
pp. 303-313 ◽  
Author(s):  
L. H. Taber ◽  
A. Paredes ◽  
W. P. Glezen ◽  
R. B. Couch
Keyword(s):  
Influenza Virus ◽  
Low Income ◽  
Influenza A ◽  
Direct Consequence ◽  
School Aged Children ◽  
Low Income Groups ◽  
H3n2 Influenza ◽  
One Year ◽  
Original Antigenic Sin ◽  
H3n2 Influenza Virus

SUMMARYIn 1976, an epidemic caused by infections with an influenza virus antigenically similar to A/Victoria/75 (H3N2) occurred in Houston, Texas. During this outbreak, 37 families (155 members) enrolled in the Houston Family Study were under observation. The families lived throughout the metropolitan area (Houston, Texas), and were representative of low income groups. The overall frequency of infection in family members was 27·7%. The frequency of infection was the highest for infants under one year of age and for their older siblings, 14 (37·8%) of 37 and 17 (33·3%) of 51, respectively. Eighteen (48·6%) of the 37 families had at least one infected member. Twelve of the 18 ‘infected’ families had school aged children, whereas only three of the 19 ‘non-infected’ families had school aged children (P < 0·01). These infected families were also larger and had increased household density (persons/rooms). The levels of pre-existing HI antibodies to A/Victoria/75 and A/Port Chalmers/73 were inversely related to frequencies of infection and illness associated with A/Victoria/75 virus. Three children required hospitalization as direct consequence of their infection with this H3N2 influenza virus. Antibody response to infection was related to previous experience with antigenically-related influenza A (H3N2) viruses according to Francis', ‘doctrine of original antigenic sin.’

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