scholarly journals Single radial haemolysis: a survey of antibody titres in the Highland Region of Scotland to recent strains of Influenza A

1978 ◽  
Vol 80 (1) ◽  
pp. 1-11 ◽  
Author(s):  
A. W. L. Joss ◽  
J. K. McPherson ◽  
H. Williams
Keyword(s):  
Influenza A ◽  
Human Populations ◽  
High Antibody ◽  
Highland Region ◽  
Preliminary Examination ◽  
Remote Island ◽  
Antibody Titres ◽  
Island Communities ◽  
Virus Isolates ◽  
Haemolysis Test

SUMMARYThe single radial haemolysis test is conveniently practical and economical and promises to have wide applicability in the study of influenza antibodies in human populations. It can also be adapted for preliminary examination of new virus isolates during epidemics.Using this test a rather higher proportion of the population in the Highland Region of Scotland was found to possess antibody to a recent epidemic strain of influenza (A/Scotland/74) than was the case in the south of England. Antibody was detected and apparently evenly spread throughout all but the most remote island communities. Some evidence of the spread of the subsequent variant, A/Victoria/75, was obtained. Most of the school children in our study had high antibody titres to recent strains but the proportion with high antibody titres to these strains declined speedily from the age of 17 years onwards.

scholarly journals Postnatal decline of maternally acquired viral antibodies of different specificities

1971 ◽  
Vol 69 (3) ◽  
pp. 435-444 ◽  
Author(s):  
M. J. Cloonan ◽  
R. A. Hawkes ◽  
L. H. Stevens
Keyword(s):  
Antibody Titre ◽  
Half Life ◽  
Influenza A ◽  
High Antibody ◽  
Serum Antibodies ◽  
Rectangular Hyperbola ◽  
Viral Antibodies ◽  
Antibody Titres ◽  
Type 3 ◽  
Rubella Antibody

SUMMARYThe rates of decline (half-lives) of maternally acquired antibodies of two different specificities in a group of infants were found to be highly variable, ranging from 18 to 192 days for parainfluenza type 3 antibody (54 infants) and from 15 to 251 days for influenza A2 antibody (nine infants). For antibodies of both specificities approximately 75% of the half-lives were between 15 and 60 days. With parainfluenza type 3 antibody, and possibly with influenza A 2 antibody, the half-lives were inversely proportional to the initial antibody titre of the babies' sera. This relationship could be described by a rectangular hyperbola. Babies with high antibody titres at birth lost this antibody rapidly whereas in babies with low initial titres antibody declined over a longer period.The half-lives of parainfluenza type 3 antibody and influenza A 2 antibody were compared with that of rubella antibody in the same group of infants (previously published). Maternally acquired viral antibodies of different specificities did not necessarily decline at similar rates in any given child. In nine infants, maternally acquired antibodies of two different specificities (rubella and parainfluenza type 3) declined at significantly different rates in the same child. It is suggested that although the half-life of antibody of a given specificity is related to its concentration in the serum, it is independent of the level of serum antibodies of other specificities.

scholarly journals Whole-Genome Sequences of Influenza A(H1N1)pdm09 Virus Isolates from Kerala, India

2017 ◽  
Vol 5 (28) ◽  
Author(s):  
Sara Jones ◽  
Raji Prasad ◽  
Anjana S. Nair ◽  
Sanjai Dharmaseelan ◽  
Remya Usha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Analysis ◽  
Influenza A ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
H1n1 Pandemic ◽  
Genome Sequences ◽  
Influenza A H1n1 ◽  
Virus Isolates ◽  
New Mutations

ABSTRACT We report here the whole-genome sequence of six clinical isolates of influenza A(H1N1)pdm09, isolated from Kerala, India. Amino acid analysis of all gene segments from the A(H1N1)pdm09 isolates obtained in 2014 and 2015 identified several new mutations compared to the 2009 A(H1N1) pandemic strain.

scholarly journals Impact of Influenza A Virus Shutoff Proteins on Host Immune Responses

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 629
Author(s):  
Megan M. Dunagan ◽  
Kala Hardy ◽  
Toru Takimoto
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Influenza A Virus ◽  
Influenza A ◽  
Human Populations ◽  
Lymphocyte Migration ◽  
Host Immune Responses ◽  
Mhc Molecules ◽  
The Impact

Influenza A virus (IAV) is a significant human pathogen that causes seasonal epidemics. Although various types of vaccines are available, IAVs still circulate among human populations, possibly due to their ability to circumvent host immune responses. IAV expresses two host shutoff proteins, PA-X and NS1, which antagonize the host innate immune response. By transcriptomic analysis, we previously showed that PA-X is a major contributor for general shutoff, while shutoff active NS1 specifically inhibits the expression of host cytokines, MHC molecules, and genes involved in innate immunity in cultured human cells. So far, the impact of these shutoff proteins in the acquired immune response in vivo has not been determined in detail. In this study, we analyzed the effects of PA-X and NS1 shutoff activities on immune response using recombinant influenza A/California/04/2009 viruses containing mutations affecting the expression of shutoff active PA-X and NS1 in a mouse model. Our data indicate that the virus without shutoff activities induced the strongest T and B cell responses. Both PA-X and NS1 reduced host immune responses, but shutoff active NS1 most effectively suppressed lymphocyte migration to the lungs, antibody production, and the generation of IAV specific CD4+ and CD8+ T cells. NS1 also prevented the generation of protective immunity against a heterologous virus challenge. These data indicate that shutoff active NS1 plays a major role in suppressing host immune responses against IAV infection.

scholarly journals Some observations on the epidemiology of toxoplasmosis in Canada

1976 ◽  
Vol 77 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Ian R. Tizard ◽  
Norman A. Fish ◽  
Joseph P. Quinn
Keyword(s):  
Toxoplasma Gondii ◽  
Placental Transfer ◽  
Summer Rainfall ◽  
Disease Prevalence ◽  
High Antibody ◽  
Toxoplasma Infection ◽  
Patient Age ◽  
Patient Âgé ◽  
Antibody Titres ◽  
Dry Conditions

SUMMARYBetween 1961 and 1974, 11934 samples of serum were tested by the Sabin- Feldman Dye test for the presence of antibodies to Toxoplasma gondii.Analysis of high-titred sera suggested that a 6-year cycle of high disease prevalence occurred across Canada. In addition, a decline in the percentage of positive reactions occurred each year in the Fall. The suggestion that this decline was due to dry conditions during the summer months was supported by the observation that differences in the prevalence of toxoplasma infection in ten Canadian cities were related to their average summer rainfall. The significance of these observations in relation to the epidemiology of toxoplasmosis in this country is discussed. The influence of patient age on the prevalence of infection was also investigated; the results obtained suggested that at least 75% of infants with high antibody titres against T. gondii had obtained these antibodies by placental transfer from their mothers.

scholarly journals Evaluating the fitness of PA/I38T-substituted influenza A viruses with reduced baloxavir susceptibility in a competitive mixtures ferret model

2020 ◽  
Author(s):  
Leo YY Lee ◽  
Jie Zhou ◽  
Paulina Koszalka ◽  
Rebecca Frise ◽  
Rubaiyea Farrukee ◽  
...  
Keyword(s):  
Influenza A ◽  
Relative Fitness ◽  
Replication Capacity ◽  
Wild Type ◽  
Influenza A Viruses ◽  
Widespread Occurrence ◽  
Host Fitness ◽  
Recombinant Viruses ◽  
Risk Patients ◽  
Virus Isolates

AbstractBaloxavir is approved in several countries for the treatment of uncomplicated influenza in otherwise-healthy and high-risk patients. Treatment-emergent viruses with reduced susceptibility to baloxavir have been detected in clinical trials, but the likelihood of widespread occurrence depends on replication capacity and onward transmission. We evaluated the fitness of A/H3N2 and A/H1N1pdm09 viruses with the polymerase acidic I38T-variant conferring reduced susceptibility to baloxavir relative to wild-type (WT) viruses, using a competitive mixture ferret model, recombinant viruses and patient-derived virus isolates. The A/H3N2 I38T virus showed a reduction in within-host fitness but comparable between-host fitness to the WT virus, while the A/H1N1pdm09 I38T virus had broadly similar within-host fitness but substantially lower between-host fitness. Although I38T viruses replicate and transmit between ferrets, our data suggest that viruses with this amino acid substitution have lower fitness relative to WT and this relative fitness cost was greater in A/H1N1pdm09 viruses than in A/H3N2 viruses.

Rapid subtyping of influenza A virus isolates by membrane fluorescence

1979 ◽  
Vol 9 (2) ◽  
pp. 269-273
Author(s):  
M Fishaut ◽  
K McIntosh ◽  
G Meiklejohn
Keyword(s):  
Influenza A Virus ◽  
Hemagglutination Inhibition ◽  
Influenza A ◽  
Cultured Cells ◽  
Fluorescent Antibody ◽  
Accurate Method ◽  
Kidney Cells ◽  
Influenza A Viruses ◽  
Indirect Immunofluorescence Technique ◽  
Virus Isolates

During the winter of 1977-1978 three influenza A virus serotypes (A/Vic/3/75, A/Texas/1/77 [both H3N2], and A/USSR/90/77 [H1N1]) circulated in Denver, offering us the opportunity to apply fluorescent antibody techniques to the specific identification of these viruses. Surface antigens of infected, unfixed primary monkey kidney cells were stained in suspension by an indirect immunofluorescence technique with anti-H3N2 and anti-H1N1 antisera. In tests of cells infected with known viruses, the members of the H3N2 family could not be distinguished from one another, but were easily distinguished from H1N1 strains. A total of 101 hemadsorption-positive clinical specimens were evaluated over a 6-month period. Forty-five of 48 influenza A H3N2 and 24 of 29 H1N1 specimens confirmed by hemagglutination inhibition were correctly identified by membrane fluorescence of cultured cells, with no misidentifications among influenza strains and with 1 false positive among 24 non-influenza isolates. The average time to identification by this technique was 4 days compared to 7 days by hemagglutination inhibition. Live cell membrane fluorescence is a simple, rapid, and accurate method for identifying and grouping influenza A viruses.

scholarly journals Molecular Basis for the Generation in Pigs of Influenza A Viruses with Pandemic Potential

1998 ◽  
Vol 72 (9) ◽  
pp. 7367-7373 ◽  
Author(s):  
Toshihiro Ito ◽  
J. Nelson S. S. Couceiro ◽  
Sørge Kelm ◽  
Linda G. Baum ◽  
Scott Krauss ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Structural Basis ◽  
Human Populations ◽  
Influenza A Viruses ◽  
Human Virus ◽  
Surface Receptors ◽  
Virus Receptors ◽  
Avian Influenza A Virus

ABSTRACT Genetic and biologic observations suggest that pigs may serve as “mixing vessels” for the generation of human-avian influenza A virus reassortants, similar to those responsible for the 1957 and 1968 pandemics. Here we demonstrate a structural basis for this hypothesis. Cell surface receptors for both human and avian influenza viruses were identified in the pig trachea, providing a milieu conducive to viral replication and genetic reassortment. Surprisingly, with continued replication, some avian-like swine viruses acquired the ability to recognize human virus receptors, raising the possibility of their direct transmission to human populations. These findings help to explain the emergence of pandemic influenza viruses and support the need for continued surveillance of swine for viruses carrying avian virus genes.

scholarly journals Therapeutic challenges in two adolescent male patients with Fabry disease and high antibody titres

2020 ◽  
Vol 24 ◽  
pp. 100618
Author(s):  
Aizeddin A. Mhanni ◽  
Christiane Auray-Blais ◽  
Michel Boutin ◽  
Alie Johnston ◽  
Kaye LeMoine ◽  
...  
Keyword(s):  
Fabry Disease ◽  
Adolescent Male ◽  
High Antibody ◽  
Antibody Titres ◽  
Male Patients

A Comparison of Virulence of Influenza A Virus Isolates from Mallards in Experimentally Inoculated Turkeys

2013 ◽  
Vol 57 (4) ◽  
pp. 790-796 ◽  
Author(s):  
Shankar Mondal ◽  
Zheng Xing ◽  
Carol Cardona
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Virus Isolates

scholarly journals Genetically and Antigenically Divergent Influenza A(H9N2) Viruses Exhibit Differential Replication and Transmission Phenotypes in Mammalian Models

2020 ◽  
Vol 94 (17) ◽  
Author(s):  
Jessica A. Belser ◽  
Xiangjie Sun ◽  
Nicole Brock ◽  
Claudia Pappas ◽  
Joanna A. Pulit-Penaloza ◽  
...  
Keyword(s):  
Influenza A ◽  
Human Infection ◽  
Influenza Viruses ◽  
Human Populations ◽  
Human Respiratory Tract ◽  
Live Bird Markets ◽  
Human Infections ◽  
Live Bird

ABSTRACT Low-pathogenicity avian influenza A(H9N2) viruses, enzootic in poultry populations in Asia, are associated with fewer confirmed human infections but higher rates of seropositivity compared to A(H5) or A(H7) subtype viruses. Cocirculation of A(H5) and A(H7) viruses leads to the generation of reassortant viruses bearing A(H9N2) internal genes with markers of mammalian adaptation, warranting continued surveillance in both avian and human populations. Here, we describe active surveillance efforts in live poultry markets in Vietnam in 2018 and compare representative viruses to G1 and Y280 lineage viruses that have infected humans. Receptor binding properties, pH thresholds for HA activation, in vitro replication in human respiratory tract cells, and in vivo mammalian pathogenicity and transmissibility were investigated. While A(H9N2) viruses from both poultry and humans exhibited features associated with mammalian adaptation, one human isolate from 2018, A/Anhui-Lujiang/39/2018, exhibited increased capacity for replication and transmission, demonstrating the pandemic potential of A(H9N2) viruses. IMPORTANCE A(H9N2) influenza viruses are widespread in poultry in many parts of the world and for over 20 years have sporadically jumped species barriers to cause human infection. As these viruses continue to diversify genetically and antigenically, it is critical to closely monitor viruses responsible for human infections, to ascertain if A(H9N2) viruses are acquiring properties that make them better suited to infect and spread among humans. In this study, we describe an active poultry surveillance system established in Vietnam to identify the scope of influenza viruses present in live bird markets and the threat they pose to human health. Assessment of a recent A(H9N2) virus isolated from an individual in China in 2018 is also reported, and it was found to exhibit properties of adaptation to humans and, importantly, it shows similarities to strains isolated from the live bird markets of Vietnam.

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