Cross-Protective Potential of a Novel Monoclonal Antibody Directed against Antigenic Site B of the Hemagglutinin of Influenza A Viruses

The hemagglutinin (HA) of influenza A viruses has been classified into sixteen distinct subtypes (H1–H16) to date. The HA subtypes of influenza A viruses are principally defined as serotypes determined by neutralization or hemagglutination inhibition tests using polyclonal antisera to the respective HA subtypes, which have little cross-reactivity to the other HA subtypes. Thus, it is generally believed that the neutralizing antibodies are not broadly cross-reactive among HA subtypes. In this study, we generated a novel monoclonal antibody (MAb) specific to HA, designated MAb S139/1, which showed heterosubtypic cross-reactive neutralization and hemagglutination inhibition of influenza A viruses. This MAb was found to have broad reactivity to many other viruses (H1, H2, H3, H5, H9, and H13 subtypes) in enzyme-linked immunosorbent assays. We further found that MAb S139/1 showed neutralization and hemagglutination-inhibition activities against particular strains of H1, H2, H3, and H13 subtypes of influenza A viruses. Mutant viruses that escaped neutralization by MAb S139/1 were selected from the A/Aichi/2/68 (H3N2), A/Adachi/2/57 (H2N2), and A/WSN/33 (H1N1) strains, and sequence analysis of the HA genes of these escape mutants revealed amino acid substitutions at positions 156, 158, and 193 (H3 numbering). A molecular modeling study showed that these amino acids were located on the globular head of the HA and formed a novel conformational epitope adjacent to the receptor-binding domain of HA. Furthermore, passive immunization of mice with MAb S139/1 provided heterosubtypic protection. These results demonstrate that MAb S139/1 binds to a common antigenic site shared among a variety of HA subtypes and neutralizes viral infectivity in vitro and in vivo by affecting viral attachment to cells. The present study supports the notion that cross-reactive antibodies play some roles in heterosubtypic immunity against influenza A virus infection, and underscores the potential therapeutic utility of cross-reactive antibodies against influenza

Novel Swine Influenza Virus Subtype H3N1, United States

A new subtype H3N1 may have arisen from reassortment of a H3N2 turkey isolate, a human H1N1 isolate, and currently circulating swine viruses

Influenza AH1N2 Viruses, United Kingdom, 2001–02 Influenza Season

During the winter of 2001–02, influenza AH1N2 viruses were detected for the first time in humans in the U.K. The H1N2 viruses co-circulated with H3N2 viruses and a very small number of H1N1 viruses and were isolated in the community and hospitalized patients, predominantly from children <15 years of age. Characterization of H1N2 viruses indicated that they were antigenically and genetically homogeneous, deriving the hemagglutinin (HA) gene from recently circulating A/New Caledonia/20/99-like H1N1 viruses, whereas the other seven genes originated from recently circulating H3N2 viruses. Retrospective reverse transcription-polymerase chain reaction analysis of influenza A H1 viruses isolated in the U.K. during the previous winter identified a single H1N2 virus, isolated in March 2001, indicating that H1N2 viruses did not widely circulate in the U.K. before September 2001. The reassortment event is estimated to have occurred between 1999 and early 2001, and the emergence of H1N2 viruses in humans reinforces the need for frequent surveillance of circulating viruses

Стратегия производства электрической и тепловой энергии в условиях ограниченного количества топлива

Исследован обособленный генерирующий комплекс, главная особенность которого – функционирование в течение контрольного периода при жестком ограничении топливного ресурса. Назначение комплекса – производство электрической и тепловой энергии для нужд потребителя. Предложена модель управления производством для двух сценариев: при безусловном обеспечении нужд потребителя электрической энергией и обязательной реализации графика отпуска тепловой энергии. Рассмотрены особенности реализации модели для обособленной теплоэлектроцентрали (мини-ТЭЦ) с гарантированным отпуском электрической энергии потребителю, обоснованы режимы когенерации в условиях ограниченного запаса топлива безотносительно к категории потребителя. Показано, что в таких режимах общий отпуск тепловой энергии за контрольный период времени при ограниченном на данный период запасе топлива не зависит от заданного производства этого вида энергии в режимах максимальной и минимальной электрических нагрузок. Показан вариант оптимизации при выборе дополнительного источника теплоты для удовлетворения нужд потребителя. В случае выбора возобновляемого источника энергии (ВИЭ) управление комплексом когенерация – ВИЭ согласно предлагаемой стратегии позволяет минимизировать необходимую мощность ВИЭ. Основой управления производством является математическая модель генерирующего комплекса, представленная в настоящей работе. В части описания поведения сложной физической системы в целом использован энергетический подход (метод Гамильтона), который оказался весьма удобным для решения поставленной задачи, поскольку вариационные принципы не зависят от выбора системы координат. Описание турбоустановки как объекта, входящего в генерирующий комплекс и во многом определяющего связь расхода топлива и количества произведенной электрической и тепловой энергии, произведено с безусловным выполнением требования: расход топлива есть функция состояния системы. Предлагаемая стратегия когенерации в условиях жесткого ограничения количества топлива не зависит от вида используемого органического топлива и не привязана к календарным датам контрольного периода.Исследован обособленный генерирующий комплекс, главная особенность которого – функционирование в течение контрольного периода при жестком ограничении топливного ресурса. Назначение комплекса – производство электрической и тепловой энергии для нужд потребителя. Предложена модель управления производством для двух сценариев: при безусловном обеспечении нужд потребителя электрической энергией и обязательной реализации графика отпуска тепловой энергии. Рассмотрены особенности реализации модели для обособленной теплоэлектроцентрали (мини-ТЭЦ) с гарантированным отпуском электрической энергии потребителю, обоснованы режимы когенерации в условиях ограниченного запаса топлива безотносительно к категории потребителя. Показано, что в таких режимах общий отпуск тепловой энергии за контрольный период времени при ограниченном на данный период запасе топлива не зависит от заданного производства этого вида энергии в режимах максимальной и минимальной электрических нагрузок. Показан вариант оптимизации при выборе дополнительного источника теплоты для удовлетворения нужд потребителя. В случае выбора возобновляемого источника энергии (ВИЭ) управление комплексом когенерация – ВИЭ согласно предлагаемой стратегии позволяет минимизировать необходимую мощность ВИЭ. Основой управления производством является математическая модель генерирующего комплекса, представленная в настоящей работе. В части описания поведения сложной физической системы в целом использован энергетический подход (метод Гамильтона), который оказался весьма удобным для решения поставленной задачи, поскольку вариационные принципы не зависят от выбора системы координат. Описание турбоустановки как объекта, входящего в генерирующий комплекс и во многом определяющего связь расхода топлива и количества произведенной электрической и тепловой энергии, произведено с безусловным выполнением требования: расход топлива есть функция состояния системы. Предлагаемая стратегия когенерации в условиях жесткого ограничения количества топлива не зависит от вида используемого органического топлива и не привязана к календарным датам контрольного периода

Antigenic Fingerprinting of H5N1 Avian Influenza Using Convalescent Sera and Monoclonal Antibodies Reveals Potential Vaccine and Diagnostic Targets

Using whole-genome-fragment phage display libraries, Hana Golding and colleagues identify the viral epitopes recognized by serum antibodies in humans who have recovered from infection with H5N1 avian influenza

Human-Like Receptor Specificity Does Not Affect the Neuraminidase-Inhibitor Susceptibility of H5N1 Influenza Viruses

If highly pathogenic H5N1 influenza viruses acquire affinity for human rather than avian respiratory epithelium, will their susceptibility to neuraminidase (NA) inhibitors (the likely first line of defense against an influenza pandemic) change as well? Adequate pandemic preparedness requires that this question be answered. We generated and tested 31 recombinants of A/Vietnam/1203/04 (H5N1) influenza virus carrying single, double, or triple mutations located within or near the receptor binding site in the hemagglutinin (HA) glycoprotein that alter H5 HA binding affinity or specificity. To gain insight into how combinations of HA and NA mutations can affect the sensitivity of H5N1 virus to NA inhibitors, we also rescued viruses carrying the HA changes together with the H274Y NA substitution, which was reported to confer resistance to the NA inhibitor oseltamivir. Twenty viruses were genetically stable. The triple N158S/Q226L/N248D HA mutation (which eliminates a glycosylation site at position 158) caused a switch from avian to human receptor specificity. In cultures of differentiated human airway epithelial (NHBE) cells, which provide an ex vivo model that recapitulates the receptors in the human respiratory tract, none of the HA-mutant recombinants showed reduced susceptibility to antiviral drugs (oseltamivir or zanamivir). This finding was consistent with the results of NA enzyme inhibition assay, which appears to predict influenza virus susceptibility in vivo. Therefore, acquisition of human-like receptor specificity does not affect susceptibility to NA inhibitors. Sequence analysis of the NA gene alone, rather than analysis of both the NA and HA genes, and phenotypic assays in NHBE cells are likely to adequately identify drug-resistant H5N1 variants isolated from humans during an outbreak

Combination Therapy Using Chimeric Monoclonal Antibodies Protects Mice from Lethal H5N1 Infection and Prevents Formation of Escape Mutants

10.1371/journal.pone.0005672PLoS ONE4

Avian Influenza Virus Glycoproteins Restrict Virus Replication and Spread through Human Airway Epithelium at Temperatures of the Proximal Airways

Transmission of avian influenza viruses from bird to human is a rare event even though avian influenza viruses infect the ciliated epithelium of human airways in vitro and ex vivo. Using an in vitro model of human ciliated airway epithelium (HAE), we demonstrate that while human and avian influenza viruses efficiently infect at temperatures of the human distal airways (37°C), avian, but not human, influenza viruses are restricted for infection at the cooler temperatures of the human proximal airways (32°C). These data support the hypothesis that avian influenza viruses, ordinarily adapted to the temperature of the avian enteric tract (40°C), rarely infect humans, in part due to differences in host airway regional temperatures. Previously, a critical residue at position 627 in the avian influenza virus polymerase subunit, PB2, was identified as conferring temperature-dependency in mammalian cells. Here, we use reverse genetics to show that avianization of residue 627 attenuates a human virus, but does not account for the different infection between 32°C and 37°C. To determine the mechanism of temperature restriction of avian influenza viruses in HAE at 32°C, we generated recombinant human influenza viruses in either the A/Victoria/3/75 (H3N2) or A/PR/8/34 (H1N1) genetic background that contained avian or avian-like glycoproteins. Two of these viruses, A/Victoria/3/75 with L226Q and S228G mutations in hemagglutinin (HA) and neuraminidase (NA) from A/Chick/Italy/1347/99 and A/PR/8/34 containing the H7 and N1 from A/Chick/Italy/1347/99, exhibited temperature restriction approaching that of wholly avian influenza viruses. These data suggest that influenza viruses bearing avian or avian-like surface glycoproteins have a reduced capacity to establish productive infection at the temperature of the human proximal airways. This temperature restriction may limit zoonotic transmission of avian influenza viruses and suggests that adaptation of avian influenza viruses to efficient infection at 32°C may represent a critical evolutionary step enabling human-to-human transmission

Two Glycosylation Sites in H5N1 Influenza Virus Hemagglutinin That Affect Binding Preference by Computer-Based Analysis

Increasing numbers of H5N1 influenza viruses (IVs) are responsible for human deaths, especially in North Africa and Southeast Asian. The binding of hemagglutinin (HA) on the viral surface to host sialic acid (SA) receptors is a requisite step in the infection process. Phylogenetic analysis reveals that H5N1 viruses can be divided into 10 clades based on their HA sequences, with most human IVs centered from clade 1 and clade 2.1 to clade 2.3. Protein sequence alignment in various clades indicates the high conservation in the receptor-binding domains (RBDs) is essential for binding with the SA receptor. Two glycosylation sites, 158N and 169N, also participate in receptor recognition. In the present work, we attempted to construct a serial H5N1 HA models including diverse glycosylated HAs to simulate the binding process with various SA receptors in silico. As the SA-α-2,3-Gal and SA-α-2,6-Gal receptor adopted two distinctive topologies, straight and fishhook-like, respectively, the presence of N-glycans at 158N would decrease the affinity of HA for all of the receptors, particularly SA-α-2,6-Gal analogs. The steric clashes of the huge glycans shown at another glycosylation site, 169N, located on an adjacent HA monomer, would be more effective in preventing the binding of SA-α-2,3-Gal analogs