Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| ultrastructural localization by immunoperoxidase techniques of influenza virus antigens in abortive infection of l cells. | an abortive infection was induced in l cells by influenza virus a/hong kong/68 (h3n2). with the use of antibody and peroxidase-labelled protein a, the localization of virus protein synthesis but not the maturation of virus particles was demonstrated at the ultrastructural level. five days after inoculation (p.i.), the synthesis of viral haemagglutinin was localized in the region of the rough endoplasmic reticulum; at late intervals p.i., haemagglutinin accumulated in the plasma membranes, where ... | 1981 | 6120640 |
| the relation of interferon and nonspecific inhibitors to virus levels in nasal washes of ferrets infected with influenza viruses of differing virulence. | two clones (7a, virulent; 64d, attenuated) of a recombinant influenza virus (a/pr/8/34-a/england/939/69 (h3n2)) were inactivated at the same rate by viral inhibitors present in nasal washes taken from both clone 7a- and clone 64d-infected ferrets. both clones induced similar levels of interferon in the nasal washes of infected animals. the onset and rise of interferon production occurred at the same time for both clones, and was associated with a decline in virus titres. in addition, both clones ... | 1981 | 6164382 |
| in vitro antibody response to influenza virus. ii. specificity of helper t cell recognizing hemagglutinin. | intraperitoneal immunization of mice with liver influenza virus was shown to induce helper t (th) cells with specificity for the hemagglutinin (ha). the interaction of virus-primed th cells with purified ha was studied independently of b cell reactivity to the same antigen by using the generation of nonspecific help as an index of activation of ha-specific th cells. th cells from mice primed with any of the h3 viruses a/aichi/68 x a/bel/42 (h3n1), a/memphis/102/72 x a/bel/42 (h3n1) or a/port cha ... | 1981 | 6166681 |
| mechanism of antigenic drift in influenza virus. amino acid sequence changes in an antigenically active region of hong kong (h3n2) influenza virus hemagglutinin. | 1981 | 6167724 | |
| [new antigenic determinant in the makeup of influenza type a(h3n2) virus hemagglutinins]. | influenza a (h3n2) viruses isolated during 1979 influenza epidemic are characterized by the presence in their hemagglutinins of both antigens similar to those found in previous isolates of the same type and a qualitatively new antigenic determinant also found in the hemagglutinin of h/south australia/1/77 virus. | 1981 | 6168113 |
| [ability of influenza virus strains to induce interferon and their sensitivity to the action of exogenous interferon]. | investigation of 112 influenza a (h1n1 and h3n2) virus strains isolated in different years demonstrated their different interferon-inducing activity. the detection of strain differences in the process of interferon production is very important for the study of influenza infection pathogenicity. of special importance are the studies of influenza virus strain sensitivity to the effect of exogenous interferon. overcoming of resistance to interferon is important for effective influenza control. the ... | 1981 | 6168114 |
| [antiviral action of swine leukocyte interferon in mouse experiments]. | swine leukocytes had previously been found to produce interferon which has an antiviral effect not only in swine cells but also in human cells. preliminary experiments in tissue cultures showed the culture of primarily trypsinized mouse embryo fibroblasts to be as sensitive to swine interferon as human diploid cells. the experiment studying the antiviral effect of swine leukocyte interferon in the animals demonstrated it to protect mice against the pathogenic a/aishi/68 (h3n2) strain; with a red ... | 1981 | 6171098 |
| genome analysis of influenza a virus strains isolated during an epidemic of 1979-1980. | the genome and polypeptides of influenza a virus h3n2 strains isolated during the epidemic of 1979-1980 in the u.s.s.r. and g.d.r. have been analysed. five varieties of h3n2 strains differing in a number of genes have been found. the isolates of the first group was similar to the a/texas/1/77 strain in all the genes; the isolates of the second group were similar to the a/bangkok/1/79 strain in all the genes; the strain representative of the third variety, contained all the genes except gene 4 cl ... | 1981 | 6171610 |
| antigenic and genetic analysis of a/hong kong (h3n2) influenza viruses isolated from swine and man. | two h3n2 strains of influenza a virus isolated from pigs in japan and thailand were characterized antigenically and genetically. a/swine/wadayama/5/69 (isolated in japan in 1969) was antigenically similar to a human strain, a/aichi/2/68, while a/swine/bangkok/9/78 (a swine isolate in thailand) was closely related to a/bangkok/36/78, a contemporary human isolate. gel electrophoresis and oligonucleotide mapping of the virus rna revealed genetic similarity between a/swine/wadayama/5/69 and a/aichi/ ... | 1981 | 6171614 |
| frequency of naturally occurring antibody to influenza virus antigenic variants selected in vitro with monoclonal antibody. | antigenic variants of a/texas/77 (h3n2) virus were selected in vitro using monoclonal antibody to virus haemagglutinin (ha). the antigenic variants and parental a/texas/77 viruses were used to to evaluate the frequency of anti-ha antibodies in the sera of children and adults using single-radial-haemolysis (srh) tests. twenty to 41% of selected sera from adults, which contained antibody to the parental a/texas/77 virus, failed to react with the different antigenic mutant viruses. a higher proport ... | 1981 | 7288173 |
| differential distribution of virus and histological damage in the lower respiratory tract of ferrets infected with influenza viruses of differing virulence. | the distribution of four strains of influenza virus [a/pr/8/34 (h0n1) and clone 64d (attenuated for ferrets) and clones 64c and 7a (virulent for ferrets) of the recombinant virus a/pr/8/34--a/england/939/69 (h3n2)] in the lower respiratory tract (trachea, bronchi and the hilar, intermediate and outer alveolar zones of the lung) of ferrets was monitored daily for 4 days after intranasal inoculation. on day 1, some animals had high virus titres in all the tissues but in other animals virus was und ... | 1981 | 7288401 |
| in vitro production of anti-influenza virus antibody after intranasal inoculation with cold-adapted influenza virus. | we have studied the production of anti-influenza virus antibody in vitro by peripheral blood mononuclear cells (pbmc) obtained from 7 normal volunteers at various times after intranasal inoculation with cold-adapted a/alaska/6/77 [h3n2] influenza virus. antibody released into culture supernatants was assayed by a 2-step enzyme-linked immunosorbent assay (elisa). cells obtained 6 days after intranasal inoculation spontaneously released both igg and iga anti-influenza antibody; this antibody produ ... | 1981 | 7299119 |
| study of recombinants derived from autochthonous influenza virus type a strains. | simultaneous inoculation of chick embryos with a standard laboratory influenza virus--a/pr8/34 (h0n1)--and with an autochthonous epidemic strain--belonging to the antigenic subtype a(h1n1) of a(h3n2), respectively--resulted in the isolation of two genetic recombinants, designated r1ivn (h1n1) and r2ivn (h3n2). each recombinant was antigenically identical to its wild-type parent and exhibited a hemagglutinating titer in chick embryos about 4-fold greater than that of the autochthonous parental st ... | 1981 | 7303494 |
| intratypic electrophoretic variation of structural and non-structural polypeptides of human influenza a viruses. | intratypic electrophoretic mobility differences in high resolution sds-polyacrylamide gels were detected between corresponding matrix (m) proteins, nucleoproteins (np), haemagglutinin (ha) and the non-structural polypeptides ns1 and ns2 induced in vero cells by human influenza a viruses of the antigenic subtypes h1n1 and h3n2. such phenotypic differences were distinguishable in both h1n1 and h3n2 viruses isolated in single school and city outbreaks. additional intratypic variation was detected i ... | 1981 | 7310381 |
| isolation and serological characterization of influenza a virus from a pig in thailand. | a hemagglutinating agent was isolated from a pig in thailand in 1978 during the early febrile stage of an influenza-like illness and identified as influenza a virus. the isolate contained hemagglutinin and neuraminidase antigens that were antigenically indistinguishable from those of a/tokyo/6/73 (h3n2), a port chalmers-like strain isolated in japan. serological tests also indicated that prevalence of h3n2 virus in the swine population in thailand. | 1981 | 7311111 |
| [role of mutations and recombinations in the epidemiology of influenza]. | influenza virus demonstrates several levels of antigenic variations, drifts and shifts, which help it to escape to herd immunity pressures. recent examples show the importance of such variations in the succession and continuity of epidemiological manifestations. during the last few years, simultaneous circulation of several subtypes of influenza a was observed while in the past, one subtype was replacing the other. thus in 1981, for the only subtype h3n2, a/texas, a/bangkok and a/intermediate te ... | 1981 | 7316613 |
| [epidemiological characteristics of influenza caused by the a(h3n2) virus in moldavia between 1969 and 1980]. | 1981 | 7330563 | |
| growth of avian and human influenza viruses in organ cultures of duck and chicken colons. | colons from ducks and chicken 1, 7, 14 and 28 days old maintained near-normal morphology up to 48 and 96 hours respectively in a system using nctc135 medium (a part) + dulbecco's modified eagle's medium (9 parts ), at 37 degrees c and 95 per cent o2/5 per cent co2. in the colon of 1 and 28 day-old ducks, duck influenza virus (hav7n2) and budgerigar influenza virus (hav4nav1) grew to peak titer by hour 72, whereas human influenza virus (h3n2) did not grow. in the colon of 1 day-old chicken, the t ... | 1981 | 7332490 |
| comparative immunogenicity of live influenza viruses and their solubilized neuraminidases: results of mouse protection experiments. | antigenicity and immunogenicity of three influenza virus strains a/pr/8/34 (h1n1). a/hong kong/1/68 (h3n2) and a/port chalmers/1/73 (h-3h2) were assayed comparatively with their corresponding neuraminidase isolated by proteolysis, and with the recombinant virus x-42 (heq1 n2). it was concluded that intranasal immunization of mice with live virus induced heterologous immunity. except in homologous neuraminidase-vaccinated mice, the subunit always was shown less effective and demonstrated a signif ... | 1981 | 7332493 |
| [comparative study of the polypeptide composition of influenza a viruses sensitive and resistant to remantadine]. | the polypeptide composition of influenza a fpv (hav1n1) and a/texas/1/77 (h3n2) viruses which had acquired resistance to remantadine after serial passages in cell cultures in the presence of the drug was studied. it was found that in parallel with the acquired resistance to remantadine the molecular weight of the heavy chain of hemagglutinin changed only in the course of cell culture passages. the influenza a/texas/1/77 virus passaged in chick embryos in the presence of remantadine exhibited no ... | 1981 | 7336680 |
| [results of a study of collective immunity to influenza a virus (h1n1) from 1976 to 1980]. | the time course of the levels of circulating antihemagglutinins to influenza a (h1n1) virus in the populations of the towns in different geographical zones of the ussr was shown to be similar. the intensity of herd immunity in some areas differed considerably, however. the population of older age groups most of whom had no clinically manifest diseases during the influenza a (h1n1) epidemic was shown to experience immunological changes upon exposure to this agent. the intensity and the rate of ch ... | 1981 | 7336683 |
| [grouping of the ns1 nonstructural proteins of influenza a viruses]. | peptide mapping was used for comparative analysis of nonstructural proteins (ns1) of 21 strains of human and animal influenza a viruses. at least 4 groups of ns1 proteins could be distinguished by the analysis of the peptide maps; we designated these groups as 0, 1, 2, and 3. group o includes ns1 proteins of human influenza virus serotype hon1, group 1 - ns1 proteins of viruses of serotypes h1n1 and h2n2, group 2 - ns1 proteins of viruses of serotype h3n2. ns1 proteins of avian influenza viruses ... | 1981 | 7336689 |
| [cross protection in mice immunized with different anti-influenza preparations]. | observations in white mice demonstrated the development of resistance to influenza type a virus (h3n2 and h0n1) after vaccination against influenza a (h1n1). the most marked cross protection between these serotypes developed after combined use of inactivated and live moderately attenuated vaccines. the resistance to the homologous influenza a (h1n1) virus after vaccination with different influenza vaccines used by various schedules was approximately similar. the role of common antigens and cellu ... | 1981 | 7336695 |
| a study of excess mortality during influenza epidemics in the united states, 1968-1976. | the effect of epidemics of influenza a on mortality in the united states was assessed by studying the monthly numbers of deaths during the years 1968-1976. deaths from all causes at all ages and among persons aged 65 and over, and also deaths from acute respiratory diseases, and from cardiovascular causes were studied. deaths from acute respiratory diseases were closely correlated with those from influenza and were taken to be an indication of the severity of influenza outbreaks. this indicator ... | 1981 | 7457477 |
| strain specificity of serum antibody to the haemagglutinin of influenza a (h3n2) viruses in children following immunization or natural infection. | the specificity of serum anti-ha antibody from children immunized or infected with a/victoria/75 (h3n2 or a/texas/77 (h3n2) virus was examined using the single radial haemolysis test together with adsorption of antibody with three antigenic variants a/hong kong/68 (h3n2), a/port chalmers/73 (h3n2) and a/victoria/75 (h3n2). the majority of young children reacted to vaccination or infection by producing strain-specific (ss) antibody to the homologous virus. a small proportion of children's sera co ... | 1981 | 7462596 |
| infection with influenza a/victoria virus in houston families, 1976. | in 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 o ... | 1981 | 7016989 |
| the antigenicity of whole virus versus subunit trivalent influenza vaccines -- a field trial in the israel defence forces, 1978. | a single dose of a commercial trivalent influenza subunit vaccine (sv) and two whole virus vaccines (wvv) were compared in a randomized, placebo-controlled field trial of subjects under 23 years of age in the israel defence forces. sixty percent of sv recipients and 29% and 37% of wvv recipients showed no measurable response to the h1n1 subtype (a/ussr). when the prevaccination titer to h1n1 was less than 10, sv did not differ significantly from the placebo, and when greater than or equal to 10, ... | 1981 | 7029236 |
| antigenicity in hamsters of inactivated vaccines prepared from recombinant influenza viruses. | inactivated vaccines prepared form influenza virus strains obtained by the recombination of a/pr/8/34 (h1n1) or a/fm/1/47 (h1n1) viruses with a/victoria/3/75 (h3n2) virus, were tested for their antigenicity in hamsters. the parental origin of the genes of each cloned recombinant virus was determined by polyacrylamide gel electrophoresis, and vaccines prepared from each strain by concentration, purification on sucrose density gradients and inactivation with formalin. all the recombinant strains u ... | 1981 | 7031128 |
| a clearance test in mice using non-adapted viruses to determine the immunogenicity of influenza strains. | a test for the immunogenicity of influenza viruses is described, which is based upon the intranasal vaccinating dose required to induce inhibition of multiplication of unadapted influenza viruses in the lungs of mice. this test is more sensitive than an antigen extinction procedure, in which immunogenicity is measured according to the dose required to induce the formation of hemagglutination-inhibition antibody. the clearance test has been used to demonstrate that a) influenza a/northern territo ... | 1981 | 7036956 |
| serologic responses to nonprevalent influenza a viruses during intercyclic periods. | sera collected at different times in the course of the tecumseh study of respiratory illness have been tested for the presence of antibodies to a variety of nonprevalent human and animal type a influenza viruses. in sera collected during the 1966-1968 period of h2n2 prevalence, rises in antibody titer were detected against the h3 antigen. the frequency of these rises in titer increased gradually and significantly as the time of emergence of the h3n2 virus approached. occasional rises in hsw1 ant ... | 1981 | 7193408 |
| sequence of dna complementary to a small rna segment of influenza virus a/nt/60/68. | a small rna segment from the influenza virus strain a/nt/60/68 (h3n2) was converted to cdna and then to double-stranded dna using synthetic oligodeoxynucleotide primers. the double-stranded form was cloned into the bacteriophage m1 3mp7. clones yielding single-strand recombinant templates in opposite orientation were sequenced by the sanger dideoxynucleotide chain termination technique. the small viral rna was 422 nucleotides long and the evidence indicated that it was formed by internal deletio ... | 1981 | 7243594 |
| investigations on the risk of virus infection in dental surgery. preliminary data. | four virus strains -- influenza a/texas 1/77 (h3n2) an a/ussr 90/77 (h1n1), adenovirus and parainfluenza type 2 -- were isolated from different specimens collected in dental surgery rooms. high levels of antibodies to respiratory viruses (influenza, parainfluenza 1, 2 and 3), adeno-, cytomegalic and herpes viruses, as well as the presence of hbsag and anti-hbs could be detected in sera from patients hospitalized for dento-maxillofacial surgery. an epidemiological survey among dentists and dental ... | 1981 | 7245605 |
| evaluation of a/alaska/6/77 (h3n2) cold-adapted recombinant viruses derived from a/ann arbor/6/60 cold-adapted donor virus in adult seronegative volunteers. | the influenza a/ann arbor/6/60 (h2n2) cold-adapted (ca) virus was evaluated as a donor of attenuating genes to new variants of influenza a virus. this ca donor virus was mated with the a/alaska/6/77 (h3n2) wild-type virus, and three a/alaska/6/77 (h3n2) ca recombinant viruses were produced. the parental origin of the genes in the three ca recombinants had been determined previously (2), and their virulence for adult seronegative volunteers was assessed in the present study to identify the genes ... | 1981 | 7251144 |
| conservation of the influenza virus membrane protein (m1) amino acid sequence and an open reading frame of rna segment 7 encoding a second protein (m2) in h1n1 and h3n2 strains. | 1981 | 7257189 | |
| [grouping of influenza a virus np proteins]. | a comparative study of influenza a virus np proteins was carried out using peptide mapping. thirty-five strains of all main serotypes of human and animal viruses were tested. the greatest diversity was found in np proteins of human influenza viruses belonging to different serotypes, while within serotypes the variability is less pronounced. four main groups of np proteins were distinguished and designated np0, np1, np2, and np3. the np0 group includes proteins of viruses of hon1 serotype, np pro ... | 1981 | 7257320 |
| inactivated chromatographic influenza vaccine. | the characteristics of laboratory parameters of inactivated whole influenza virus vaccine, obtained by the purification of allantoic virus cultures on macroporous glass, are presented. the vaccine is characterized by small reactogenicity and safety, which allows it to be used in both adolescents and adults. seroconversions to hemagglutinin have been found in 80--95% of individuals vaccinated once during the test vaccination by the preparation containing various strains of influenza a/h3n2/virus. ... | 1981 | 7266085 |
| [comparative characteristics of influenza type a infection in adults and children during epidemics and interepidemic periods]. | parallel serological examinations by cft and hi test of paired sera from 18,557 patients and normal subjects in the period of influenza a/hong kong (h3n2) subtype virus in 1969-1976 revealed similar sensitivity of both methods for influenza diagnosis during epidemics, however in the interepidemic periods in these years the cft was found to be more sensitive than hi. this observation referred to all age groups of the examined subjects with manifest or asymptomatic forms of influenza infection. in ... | 1981 | 7269525 |
| principles of selective inactivation of viral genome. i. uv-induced inactivation of influenza virus. | photosensitivity of infectious, haemagglutinating and neuraminidase activities of influenza virus has been determined experimentally. the photosensitivity of infectious activity of type b (strain hongkong/8/73) influenza virus ws found to be higher than that of type a strains nib-4 (n3n2-3), leningrad/399/76 (h3n2-3) and nib-6 (h1n1). the data obtained may be used for the determination of conditions of uv-irradiation for preparation of uv-inactivated antiviral vaccines. | 1981 | 7271457 |
| amino acid sequence changes in the haemagglutinin of a/hong kong (h3n2) influenza virus during the period 1968--77. | haemagglutinin molecules from nine strains of a/hong kong/68 (h3n2) influenza virus, isolated between 1968 and 1977, were examined for changes in amino acid sequences. at least 18 changes, 9 of which were located precisely, occurred in the soluble tryptic peptides of the large haemagglutinin polypeptide (ha1) during this period. these peptides contained 262 residues (82% of ha1). in ha2, only two changes in 129 residues (58% of ha2) were detected. sequential changes at a particular locus were no ... | 1980 | 6153236 |
| mitogen responses and interferon production after exposure of human macrophages to infectious and inactivated influenza viruses. | human macrophages were exposed to two influenza a viruses representing different subtypes. the donors were likely to have been exposed to one subtype (h3n2) but not to the other (h0n 1). similar effects upon the macrophages were observed for both subtypes: macrophage enhancement of mitogen-stimulated lymphocyte transformation responses was depressed, and the macrophages produced interferon. in contrast, macrophages exposed to inactivated virus exhibited normal enhancement of lymphocyte transform ... | 1980 | 6155437 |
| radioimmunoassay of influenza a virus haemagglutinin. ii. antigenic cross-reactions of influenza a (h3 subtype) viruses as determined by radioimmunoassay and haemagglutination inhibition tests. | individual rabbits differed greatly in their antibody response to the "strain-specific" and "cross-reactive" antigenic determinants on the haemagglutinin (ha) subunit of influenza virus recombinant mrc11 (h3n2) and influenza virus dunedin (h3n2), after immunization with whole virus or bromelain-released haemagglutinin (b-ha). consequently, diverse cross-reactions between htese viruses and a/hong kong/68 virus were found in the haemagglutination inhibition (hi) test as well as in homologous radio ... | 1980 | 6155774 |
| determination of the number of nonoverlapping antigenic areas on hong kong (h3n2) influenza virus hemagglutinin with monoclonal antibodies and the selection of variants with potential epidemiological significance. | 1980 | 6156537 | |
| antineuraminidase antibody response to vaccination of chickens with intact virus and different submit preparations of the influenza virus strains a/sing/1/57 (h2n2), a/hong kong/1/68 (h3n2) and a/port chalmers/1/73 (h3n2). | the antineuraminidase (an) antibody response to vaccination of chickens with intact virus and different subunit preparations of the influenza virus strains a/sing/1/57 (h2n2), a/hong kong/1/68 (h3n2) and a/pt. chalmers/1/73 (h3n2) was tested comparatively. using a photometric method capable of analysing mixtures of an antibodies against antigenically different n2 neuraminidases, it was concluded that vaccination with subunits produced by treatment with bromelain and sarkosyl can yield an antibod ... | 1980 | 6157375 |
| the presence of two neuraminidases in an influenza virus. | the wild type influenza strain a/aichi/2/68 (h3n2), when disrupted with sds and electrophoresed on cellulose acetate paper, yielded two separate neuraminidases, na(h+) and na(h-). these enzymes after extraction were biologically active and possessed different specific activities. enzyme na(h+) possessed neuraminidase as well as hemagglutinin activities whereas enzyme na(h-) demonstrated only neuraminidase activity. similar results were obtained when the aichi strain was treated with tween-ether ... | 1980 | 6157463 |
| [antigenic determinants in the makeup of the hemagglutinins of influenza virus type a (h3n2) isolated in 1977--1978]. | antigenic composition of hemagglutinins (ha) of influenza a viruses isolated during the epidemic of 1977--1978 was studied. three antigenic determinants of h3.1, h3.5 and h3.7, identical to the determinants of ha of the viruses isolated in 1975, were detected in ha of the viruses isolated in 1977--1978 by means o the hai test with inhibitor-free and monoreceptor sera. a/south australia/1/77 virus was an exception in this group of viruses, and its ha contained only two determinants, h3.5 and h3.7 ... | 1980 | 6158176 |
| effect on influenza virus infection on the production of interferon by alveolar and peritoneal cells in vitro. | the investigation was carried on mice infected with influenza a/053/74/h3n2 virus. 129/ao/boy, inbred mice, were inoculated intranasally with influenza virus. the alveolar and peritoneal cells from infected and uninfected animals were induced in vitro with newcastle disease virus. it was shown that the alveolar cells from infected mice produce more interferon than the cells from control mice, but the peritoneal cells from both groups of animals produced the same amount of interferon. | 1980 | 6158300 |
| influenza vaccination in hbsag positive chronic active hepatitis patients treated with interferon. | sixteen patients with hepatitis b antigen (hbsag) positive chronic active hepatitis (cah) were vaccinated with the nonhuman influenza a virus heq1neq1; eight patients were also treated with leucocyte interferon. pre-vaccination sera were negative for specific antibody in hemagglutination inhibition tests. four weeks after vaccination all patients had responded with a homologous antibody titer. between the interferon-treated and the untreated groups the differences in antibody titers against the ... | 1980 | 6162083 |
| comparison of the antineuraminidase antibody response to vaccination with intact virus and subunit preparations obtained by different techniques of the influenza virus strains a/sing/1/57 (h2n2), a/hong kong/1/68 (h3n2) and a/port chalmers/1/73 (h3n2). | 1980 | 6162604 | |
| the effects of shifts and drifts on the epidemiology of influenza in man. | accurate information on the epidemiology of influenza over the world is difficult to obtain as it is dependent on both national statistics of morbidity and mortality and on adequate virological confirmation of suspected cases. only a few countries have the facilities for these and in much of the world it is difficult to establish exactly the impact of influenza. for this reason, our knowledge on the natural history of the disease and the virus causing it is restricted to what happens in a few ar ... | 1980 | 6103560 |
| influenza vaccines. | inactivated influenza vaccines can now be made from purified haemagglutinin and neuraminidase. although they have not been fully tested in the field they probably produce as good an immunity as whole virus vaccines and fewer reactions. they could be used against a new serotype in the face of a pandemic. revaccination with killed vaccine may be effective, but one careful study in a school during the drifting of the h3n2 showed that it was not effective there overall. live influenza vaccines have ... | 1980 | 6103563 |
| peculiarities of obtaining attenuated thermosensitive recombinants of influenza a virus at the end of the h3n2 epidemic cycle. | the conditions of obtaining thermosensitive recombinants of the virulent a/leningrad/82/76 (h3n2) virus with two donors of attenuation, a/leningrad/134/17/57 (h2n2) and a/leningrad/9/37/46 (h0n1), were evaluated. the recombinants were obtained by various methodical approaches (hybridization of native viruses, cross-reaction and selection of recombinants at temperatures of 25, 32 and 40 degrees c) to study their effects on the degree of attenuation and the regularity of transmission of the ts mar ... | 1980 | 6106378 |
| antibodies to the strain-specific and cross-reactive determinants of the haemagglutinin of influenza h3n2 viruses. antiviral activities of the antibodies in biological systems. | antibodies to the strain-specific (ss) and cross-reactive (cr) antigenic determinants of the haemagglutinin (ha) of influenza h3n2 viruses were prepared, and their antiviral properties in experimentally infected mice and in eggs were investigated. the ss antibodies were considerably more efficient than the cr antibodies in direct virus neuralization tests. the difference in the activities of the two types of antibody preparations was less pronounced in virus growth inhibition studies in the alla ... | 1980 | 6164247 |
| antibodies to the strain-specific and cross-reactive determinants of the haemagglutinin of influenza h3n2 virus. 3. selection of antigenic variations in vitro and in vivo. | antigenic variants of influenza a/hong kong/1/68 (h3n2) were obtained in vitro by letting virus multiply in the allantosis-on-shell system in the presence of anti-haemagglutinin antibodies, prepared from immune goat serum to purified haemagglutinin antigen, and in vivo by giving mice antibody intraperitoneally one day before challenge with a sublethal dose of live virus. in both systems it was shown that the most narrowly reacting strain-specific antibodies selected antigenic variants at an appa ... | 1980 | 6164248 |
| haemagglutination-inhibition antibodies in human sera to an antigenic mutant of influenza a/texas/1/77 (h3n2) virus obtained in vitro. | an antigenic mutant of the wild influenza strain a/texas/1/77 (h3n2) was obtained in vitro by growing virus of the allantosis-on-shell system in the presence of a mouse monoclonal antibody preparation to the texas haemagglutinin (ha) antigen. a total of 204 human sera, from a population of randomly collected sera during the fall of 1979, were examined by the haemagglutination-inhibition (hi) tests against the texas wild strain and the antigenic mutant. it was shown that sera from young children ... | 1980 | 6164249 |
| the mechanism of antigenic drift in influenza viruses: analysis of hong kong (h3n2) variants with monoclonal antibodies to the hemagglutinin molecule. | monoclonal antibodies to the hemagglutinin molecule of the hong kong variant, mem/1/71 (h3n2), influenza virus were used to study antigenic drift in the h3n2 subtype of influenza viruses. antigenic variants of mem/1/71 (h3n2) were selected after a single passage of the virus in chick embryos in the presence of monoclonal antibody. the variants showed a marked reduction in the ability to react with the monoclonal antibody used in selection. the monoclonal antibodies could be divided into three gr ... | 1980 | 6164328 |
| cloning dna sequences from influenza viral rna segments. | dna sequences corresponding to gene segments that code for the nonstructural protein, the matrix protein, and the hemagglutinin of influenza a virus [strain a/udorn/72 (h3n2)] were cloned in escherichia coli pbr 322. initially, positive and negative cdna strands were prepared separately by reverse transcription. the positive strands of cdna were transcribed from genomic rna segments by using a specific dodecamer dna sequence as a primer; the negative strands of cdna were transcribed from cytopla ... | 1980 | 6244544 |
| antioncogenic activity of influenza virus on polyoma virus induced renal and brain tumors in newborn wistar rats. | simultaneous inoculation of newborn wistar rats with intact a/pr 8/34 (hon 1) influenza virus and the s.e. strain of polyoma virus resulted in significant reduction of the rates of both kidney sarcomas and brain tumors in comparison to controls given polyoma virus, only. this antioncogenic activity (aoa) of influenza virus was observed independently whether or not influenza and polyoma virus were injected on different sites or were inoculated as a combined vaccine. ether-treated a/pr 8/34 influe ... | 1980 | 6252720 |
| isolation of a recombinant influenza virus (hsw 1 n2) from swine in japan. | outbreaks of swine influenza were first observed in japan in 1978. a number of influenza viruses were isolated from diseased swine. almost all viruses isolated were swine influenza virus (hsw 1 n1) but two viruses isolated from the nasal swabs of swine showing clinical signs of influenza in the kanagawa prefecture were characterized antigenically as hsw 1 n2. analysis of swine sera showed that influenza virus hsw 1 n2 was epidemic in the farm from which the virus had been isolated. the new virus ... | 1980 | 6255900 |
| evidence of prior infection with influenza a/texas/77 (h3n2( virus in dogs with clinical parainfluenza. | eighty dogs exhibiting clinical signs of respiratory disease were sampled for influenza virus isolation and serologically tested for hemagglutination inhibiting antibody to influenza a/hong kong/68, a/victoria/75, a/texas/77 and a/ussr/77. forty-one animals without clinical signs of respiratory disease were also examined serologically. hemagglutinating agents were isolated from nasal and/or pharyngeal swabs taken from 21 of the 80 dogs with clinical respiratory disease. twenty of these 21 isolat ... | 1980 | 6256039 |
| the role of wild birds in the spread of influenza viruses. | eggs deposited by different migrating wild bird species in pond farm areas in hungary were examined for yolk antibodies to different variants of human a/h3n2 influenza virus. antibodies to victoria/75 and texas/77 occurred in 17.9 and 32.0% of gull eggs, and 5.6 and 16.4% of common tern eggs, respectively, while antibodies to a/h1n1/77 occurred in roughly similar proportions (10.2 and 13.4%) in the eggs of both species. infection of the gull and tern populations of given areas by human and avian ... | 1980 | 6258400 |
| evaluation of three strains of influenza a virus in humans and in owl, cebus, and squirrel monkeys. | the virulence of three cloned influenza a viruses was compared in humans and in three readily available species of nonhuman primates (owl, squirrel, and cebus monkeys) in an attempt to identify a species of monkey that could be used to investigate the genetic basis of attenuation of influenza a viruses for humans. three influenza a viruses from two subtypes, i.e., the a/udorn/72 (h3n2), a/alaska/77 (h3h2), and a/hong kong/77 (h1h1) viruses, produced febrile influenzal illness in humans. squirrel ... | 1980 | 6772565 |
| [comparison between killed subunit influenza vaccines and whole virion preparations: study of reactions and protective efficacy in children and adults]. | three hundred eight subjects (of whom 103 children aged 6-12 years) were vaccinated with trivalent--a/ussr/90/77 (h1n1), a/texas/1/77 (h3n2), b/hong kong/8/73 strains--influenza virus vaccines, two of them sub-unit and the third whole-virus preparation. children and adolescent received two doses with an interval of 4 weeks, adults one dose only. the results of the determination by single radial diffusion test of the hemagglutinin amount for each of the three vaccinal strains and the data of the ... | 1980 | 6778485 |
| ts p1 and p3 genes are responsible for satisfactory level of attenuation of ts-1a2 recombinants bearing h1n1 or h3n2 surface antigens of influenza a virus. | 1980 | 6893373 | |
| [subtypes h1n1 and h3n2 of influenza virus isolated from the same patient]. | 1980 | 6927787 | |
| a study of acute respiratory disease in the community of port chalmers. iii. efficacy of influenza virus subunit vaccines in 1973, 1974 and 1975. | an evaluation of the efficacy of influenza virus subunit vaccine was undertaken during a study of acute respiratory disease in the semi-isolated community of port chalmers, new zealand. in 1973, the administration of a vaccine containing a/england/42/72(h3n2) and b/roma/1/67 stains was found to produce hi antibody titres greater than or equal to 1:40 to the a and b components in 50 percent of 32 subjects. there was no significant ni antibody response to the a component. during an epidemic of a/p ... | 1980 | 6935541 |
| the replication of type a influenza viruses in the infant rat: a marker for virus attenuation. | twenty recombinant influenza virus strains bearing hsw1n1, h1n1 or h3n2 surface antigens, together with their respective wild-type or laboratory-propagated parent viruses, were inoculated into 2 day-old infant rats and their replication in the turbinates and lungs of these animals observed over a period of 5 days. in addition, the ability of each of the recombinant and parent viruses to enhance a subsequent infection of these infant rats by haemophilus influenzae type b was determined. the resul ... | 1980 | 6969291 |
| a murine model for assessment of living attenuated influenza a vaccines. | the laboratory mouse was evaluated as a model to assess the genetic stability of influenza a mutants of potential use as living vaccine strains. the growth of three mutant recombinants, a/hong kong/68-ts-1e (h3n2), a/hk/123/77x-ts-1a2 (h1n1) and a2/aa/6/60-ca(h2n2) was studied in 15 g mice. yields of ts-1e from both lungs and turbinates were ten-fold less than that of a control virus with the same surface antigens. all ts-1e isolates showed evidence of loss of ts phenotype. ts-1a2 and ca recombi ... | 1980 | 7271601 |
| neuraminidase from influenza virus a (h3n2): specificity towards several substrates and procedure of activity determination. | neuraminidase (acylneuraminyl hydrolase, ec 3.2.1.18) from the influenza virus a/hong kong/68 (h3n2) was purified after treatment of the purified virus with sarcosyl (sodium laurylsarcosinate), centrifugation at 110 000 x g, and chromatography on deae-sephadex and sephadex g-200. it migrated as a single component during electrophoresis on polyacrylamide gel, and its molecular weight was estimated about 270 000. the enzyme was thermolabile, the activity being reduced to 60% in 10 min at 50 degree ... | 1980 | 7213637 |
| evaluation of influenza a/hong kong/123/77 (h1n1) ts-1a2 and cold-adapted recombinant viruses in seronegative adult volunteers. | two attenuated influenza a donor viruses, the a/udorn/72 ts-1a2 and the a/ann arbor/6/60 cold-adapted (ca) viruses, are being evaluated for their ability to reproducibly attenuate each new variant of influenza a virus to a specific and desired level by the transfer of one or more attenuating genes. each of these donor viruses has been able to attenuate influenza a viruses belonging to the h3n2 subtype by the transfer of one or more attenuating genes. to determine whether these two donor viruses ... | 1980 | 7216417 |
| outcome of influenza infection: effect of site of initial infection and heterotypic immunity. | an infection established throughout the total respiratory tract of mice with a highly lung adapted influenza virus (h0n1) led to death from viral pneumonia. the 50% lethal dose (ld(50)) was approximately the same as the 50% infectious dose (id(50)). an infection with the same virus initiated in the nasal mucosa spread to the trachea and lungs over a 3- to 5-day period but was not lethal except at very high infecting doses. the ld(50) was 30,000 times the id(50). mice that had recovered from a pr ... | 1980 | 7216433 |
| influenza and corona-virus antibodies in the newborns and their mothers in mali (1980). | in february 1980 blood samples from 91 women and their newborn babies (cord blood) from mali have been analysed for influenza and corona oc 43 hi antibodies. the titers of influenza hi antibodies were higher in blood samples collected from the mothers at delivery than in their newborns. considering the gmt values and percentage of persons with protective titers (greater than or equal to 1:40) we may assume that influenza a (h3n2) viruses had been highly active in mali. influenza a (h1n1) and b a ... | 1980 | 7233536 |
| [epidemic of influenza in antananarivo (with isolation of virus a/texas/77 (h3n2))]. | 1980 | 7235771 | |
| protection of infants from infection with influenza a virus by transplacentally acquired antibody. | transplacentally acquired antibody to influenza a virus was measured by a microneutralization test and a radioimmunoprecipitation assay in cord blood obtained from infants at a large urban county hospital in 1975-1978. random samples tested before epidemic periods were a measure of susceptibility of the population. twenty-six infants from whom cord sera were available had culture-documented infections with influenza a/victoria (h3n2) virus when younger than four months. the direct correlation be ... | 1980 | 7462695 |
| studies with a cold-recombinant a/victoria/3/75 (h3n2) virus. i. biologic, genetic, and biochemical characterization. | a cold-recombinant virus cr 22, was derived from an attenuated cold-adapted parent strain. a/ann arbor/6/60 (h2n2), and a wild-type parent strain, a/victoria/3/75 (h3n2). antigenic analysis showed that cr 22 possesses the hemagglutinin and neruaminidase surface antigens derived from the a/victoria/3/75 (h3n2) parent. from studies of virus-induced polypeptides using polyacrylamide gel electrophoresis, it was deduced that a polymerase protein, p1, is coded and by an rna segment derived from the wi ... | 1980 | 7462696 |
| studies with a cold-recombinant a/victoria/3/75 (h3n2) virus. ii. evaluation in adult volunteers. | a cold-recombinant influenza a virus, cr 22, derived from a/ann arbor/6/60 (h2n2) cold-adapted virus and a/victoria/3/75 (h3n2) wild-type virus, was tested in adult volunteers. cr 22 induced only low-grade clinical reactions in volunteers who had low titers of serum antibodies. virus could be reisolated from about one-third of the volunteers, but only at low titers. no revertant viruses were found, and there was no evidence for transmission of virus to unvaccinated volunteers housed in the close ... | 1980 | 7462697 |
| defective interfering influenza viruses and host cells: establishment and maintenance of persistent influenza virus infection in mdbk and hela cells. | wsn (h0n1) influenza virus upon undiluted passages in different species of cells, namely, bovine kidney (mdbk), chicken embryo (cef), and hela cells, produced a varying amount of defective interfering (di) virus which correlated well with the ability of the species of cell to produce infectious virus. however, the nature of the influenza di viral rna produced from a single clonal stock was essentially identical in all three cells types, suggesting that these cells do not exert a great selective ... | 1980 | 7463559 |
| [influenza. sero-epidemiological supervision of the alitalia airline personnel (1978-1979)]. | from the autumn 1978 to the spring 1979 an epidemiological inquiry was set up concerning samplings of sera of 1648 adult of different ages and of both sexes. it was noticed a contemporaneous presence of a/texas/1/77(h3n2) and a/ussr/90/77(h1n1) viruses; it was found a larger frequency of the last subtype in the individuals born after 1957. during the winter 1978/1979 it was also noticed an overlap of b influenza virus. | 1980 | 7465100 |
| sensitivity and specificity of enzyme immunoassay for serodiagnosis of influenza a virus infections. | antibodies to influenza virus in sera from 40 patients infected with influenza a/ussr/90/77h1n1-like virus were measured by an enzyme immunoassay (eia), and results were compared with those obtained by complement-fixation (cf) and hemagglutination-inhibition (hai) tests. the sensitivity of eia in detecting an increase in influenza antibody in sera from these 40 patients was intermediate (27 of 40) between the cf test (19 of 40) and the hai test (35 of 40) when an ether-treater influenza a/ussr/7 ... | 1980 | 6989932 |
| use of the enzyme-linked immunosorbent assay to detect serum antibody responses of volunteers who received attenuated influenza a virus vaccines. | sera from volunteers who received live influenza a wild-type or ts recombinant virus were tested by hemagglutination inhibition (hi) assay, neuraminidase inhibition (ni) assay, and the enzyme-linked immunosorbent assay (elisa) to determine which assay system was the most sensitive in detecting an immunological response to infection. the elisa was performed with inactivated whole virus antigen, and the optical density at each of five serial twofold dilutions of pre- and postimmunization sera was ... | 1980 | 7011972 |
| [biological relations of selected influenza virus strains adapted to mouse lungs. i. h3n2 influenza virus study]. | 1980 | 7340409 | |
| influenza a antibodies in cervine animals. | in the haemagglutination inhibition (hi) test, 20 cervine sera, most of which came from northern germany, were treated with receptor destroying enzyme (rde) and 11 sera were found to contain antibodies against the h1n1 (a/ussr 90/77) and h3n2 (a/victoria 13/75, a/texas 1/77) influenza viruses. only two sera contained antibodies against h3n2 viruses, and seven sera were negative. evidence of the specificity of influenza antibodies was provided by the following findings: 1) the igg serum extracts ... | 1980 | 7390623 |
| human trials with wild-type h1n1 and recombinant h3n2-h1n1 influenza a viruses of 1977-1978. | a series of trials was conducted in which wild-type a/ussr/90/77 (h1n1) influenza a virus and a few of its antigenic variants were inoculated into volunteers. infections readily occurred in people of all ages who had initial low antibody titers, but clinical effects were generally mild in comparison with those of the previously tested subtypes, h0n1, h1n1, h2n2, h3n2. there was, however, an inverse relationship between severity of symptoms and age of volunteers, although the incidence of virus e ... | 1980 | 7399693 |
| temperature-sensitive mutants of influenza a virus: transfer of the two temperature-sensitive lesions in the udorn/72-ts-1a2 virus to the a2hong kong/123/77 (h1n1) wild-type virus. | the influenza a/udorn/72-ts-1a2 virus possesses temperature-sensitive mutations in the genes coding for the p1 and p3 polymerase proteins. it is being evaluated as a donor of its attenuating temperature-sensitive genes to produce recombinant live vaccine strains of epidemic variants of influenza a virus. transfer of the p1 and p3 genes to two viruses within the h3n2 subtype of influenza a virus (i.e., the a/victoria/3/75 and a/alaska/6/77 viruses) conferred on each variant the following properti ... | 1980 | 7399695 |
| naturally occurring temperature-sensitive influenza a viruses of the h1n1 and h3n2 subtypes. | seventeen of twenty-six influenza a virus isolates of the h1n1 antigenic subtype and two of eleven h3n2 virus isolates from the 1977-78 season exhibited a ts phenotype, were restricted in plaquing in mdck cells at 38.5 degrees c compared to 34 degrees c and appeared to be naturally occurring ts mutants. the cut-off temperature for two such ts h1n1 virus isolates was established as 38 degrees c. the ts viruses were as thermostable as non-ts isolates and no complementation was detected between the ... | 1980 | 7400776 |
| [features of strains of a(h3n2) influenza virus isolated during the 3 epidemics of kiev in 1972-7976]. | 1980 | 7402112 | |
| antibody response to influenza a/new jersey and a/victoria virus vaccines in 1976 and subsequent antibody levels after influenza a epidemics, 1977-1979. | antibody levels before and after vaccination were studied among schoolchildren and young adults given commercial a/new jersey/76 (hswn1), a/victoria/75 (h3n2), and b/hong kong/72 vaccines in the fall of 1976. children responded better to a single dose of the a/new jersey subvirion vaccine than had previously been observed, particularly to a new subvirion vaccine. hemagglutination-inhibiting antibody titers decreased during the first six months after vaccination but appeared stable thereafter. pe ... | 1980 | 7410896 |
| electrophoretic migration rate differences of polypeptides of human influenza a viruses: partial analysis of the genome of influenza vaccine recombinant viruses. | electrophoretic migration rate differences were detected in high resolution sds polyacrylamide gels for nucleoprotein (np), matrix protein (m), non structural protein (ns1), haemagglutinin (ha) annd, less regularly, for the polymerase polypeptides p1, p2 and p3 induced by different influenza a viruses. the technique allowed parental assignation of the corresponding genes in certain recombinant viruses including a/pr/8/34 (h0n1)--a/hk/117/77 (h1n1), a/okuda/57 (h2n2)--a/hk/119/77 (h1n1) and a/len ... | 1980 | 7416971 |
| [study results of the comprehensive influenza prevention with vaccines and remantadine during the influenza a(h1n1) outbreak in 1979]. | during an outbreak of influenza in april, 1979, caused by a (h1n1) virus the protective effect of remantadine in combination with vaccinations using a national-made live a (h3n2) and inactivated a (h1n1) and b vaccines was studied. the best protective effect was achieved in the subjects vaccinated with influenza vaccines and given remantadine for urgent prophylaxis. vaccination prophylaxis reduced the incidence of influenza and ard 1.4-fold, prophylaxis with remantadine alone 2.3-fold. | 1980 | 7423970 |
| temperature-sensitive mutants of influenza a virus: evaluation of the alaska/77-ts-1a2 temperature-sensitive recombinant virus in seronegative adult volunteers. | an influenza a virus recombinant bearing the surface antigens of the a/alaska/6/77 (h3n2) wild type virus ands the two ts genes of the a/udorn/72-ts-1a2 (h3n2) virus was evaluated for attenuation, antigenicity, and transmissibility in 28 adult volunteers all of whom possessed a preinoculation serum hemagglutination-inhibiting (hai) antibody titer of less than or equal to 1:8 and 18 of whom also possessed a serum neuraminidase-inhibiting (ni) antibody titer of less than or equal to 1:4. the alask ... | 1980 | 7425857 |
| temperature-sensitive mutants of influenza a virus. transfer of the two ts-1a2 ts lesions present in the udorn/72-ts-1a2 donor virus to the influenza a/alaska/6/77 (h3n2) wild type virus. | the udorn/72-ts-1a2 temperature-sensitive influenza a virus has a 37 degrees c shutoff temperature and a ts mutation on the genes coding for the p1 and p3 proteins. this ts donor virus was produced with the expectation that the transfer of its two ts genes would regularly and predictably attenuate each new variant of influenza a virus. it had previously been mated with the a/victoria/75 (h3n2) virus and five vic/75-ts-1a2 rcombinants were isolated that had both ts-1a2 ts genes and in vitro and i ... | 1980 | 7425858 |
| a study of live influenza virus vaccine in patients with chronic bronchitis. report to medical research council's committee on influenza and other respiratory virus vaccines. advisory group on pulmonary function tests in relation to live influenza virus vaccines. | a multicentre study of the effects of influenza virus rit 4050 (h3n2) in patients with chronic bronchitis was conducted by members of an mrc committee. the results showed that rit 4050 vaccine virus did not cause a deterioration in clinical or physiological status in these patients within the limitation of the relatively reproducible ventilatory tests which were employed. this conclusion applied equally to those who were inoculated and became infected and to those who failed to develop serologic ... | 1980 | 7426351 |
| further studies of the neuraminidase content of inactivated influenza vaccines and the neuraminidase antibody responses after vaccination of immunologically primed and unprimed populations. | purified concentrates of influenza a/ussr/90/77(h1n1)-like, a/texas/1/77 (h3n2)-like, and b/hong kong/5/72-like viruses used for preparation of investigational and licensed vaccines in 1978 to 1979 were tested for their content of neuraminidase enzyme activity. concentrates of h1n1 virus used to prepare vaccines for clinical investigations performed in the spring of 1978 had neuraminidase activity at that time which decreased during storage to almost undetectable levels (three lots) or by 50% (o ... | 1980 | 7429641 |
| influenza vaccination of elderly persons. reduction in pneumonia and influenza hospitalizations and deaths. | effectiveness of influenza vaccination in reducing pneumonia and influenza hospitalizations and deaths among elderly members of a prepaid health plan was analyzed retrospectively. two epidemics caused by the h3n2 subtype of type a influenza were studied. vaccine derived from the h2n2 subtype of influenza a virus failed to protect against the hong kong (h3n2) virus during the 1968-1969 epidemic. vaccine derived from the a/hong kong/68 (h3n2) virus yielded an estimated 72% (31% to 100%) reduction ... | 1980 | 7431593 |
| [comparative study of the proteins of influenza virus type a nucleoproteins]. | a comparative study of protein of nucleoproteins (np-protein) of influenza a viruses by peptide mapping shows its variability to be small within one drifting series and quite marked in strains belonging to different sero-types. in oligopeptide maps of np-proteins of viruses of the hong kong (h3n2) series there is a typical group of spots differing them from oligopeptide maps of np-proteins of viruses of other serotypes, particularly of the preceeding serotype h2n2 and the viruses related by hema ... | 1980 | 7434735 |
| production of an attenuated influenza a (h3n2) strain "ko-1" by recombination with a/okuda/57 (h2n2) followed by selection of inhibitor-resistant virus. | a live attenuated influenza a (h3n2) strain "ko-1" was developed by recombination of wild influenza a/kumamoto/22/76 (h3n2) with attenuated a/okuda/57 (h2n2) followed by passage in developing chick eggs in the presence of horse serum inhibitor. the virus strain "ko-1" obtained is inhibitor-resistant, and has hemagglutinating (ha) and neuraminidase (na) antigenicity derived from the wild parent virus. rna analysis revealed that one rna segment (corresponding to m protein) was derived from the a/o ... | 1980 | 7437002 |
| relationship between surface antigens of two variants of influenza a (h3n2) virus, as revealed by hemagglutination inhibition, kinetic neutralization, and neuraminidase inhibition. | rabbit antisera were raised against plaque-purified influenza virus strains of a/victoria/75 and a/texas/77 isolated from seattle influenza patients. the antigenic specificity of hemagglutinins was compared by hemagglutination inhibition (hi) and kinetic neutralization tests. anti-a/victoria/75 had equally high hi titers and neutralization rate constants (kappa values) for a/victoria/75 and a/texas/77. in contrast, anti-a/texas/77 had a high hi titer and kappa value to a/texas/77 and a low hi ti ... | 1980 | 7439992 |
| duck influenza lacking evidence of disease signs and immune response. | influenza viruses a/duck/hokkaido/5/77 (hav7n2), a/budgerigar/hokkaido/1/77 (hav4nav1), a/kumamoto/22/76 (h3n2), a/aichi/2/68 (h3n2), and a/new jersey/8/76 (hsw1n1) were experimentally inoculated into pekin ducks. of these, the influenza viruses of duck and budgerigar origin replicated in the intestinal tract of the ducks. the infected ducks shed the virus in the feces to high titers, but did not show clinical signs of disease and scarcely produced detectable serum antibodies. using immunofluore ... | 1980 | 7439994 |
| correlation between antibody titers to influenza a virus subtypes h1n1 and h3n2 as measured by hemagglutination-inhibition and hemolysis-in-gel tests. | 1980 | 7441011 | |
| enhancement of activity against influenza viruses by combinations of antiviral agents. | in an investigation of alternative therapeutic approaches for the treatment of influenza virus infections, the antiviral activities of rimantadine hydrochloride, amantadine hydrochloride, ribavirin, and combinations of these drugs were assessed in vitro. madin-darby canine kidney cell monolayers were inoculated with recent isolates of influenza viruses at low multiplicities of infection, and virus titers were determined after 24 h. the combination of rimantadine and ribavirin resulted in an enha ... | 1980 | 7447417 |
| differing virulence of h1n1 and h3n2 influenza strains. | sequential influenza a/texas/77 (h3n2) and a/ussr/77 (h1n1) epidemics occurred during the winter of 1977-1978 in two populations under viral surveillance for influenza. in college students who reported to the vanderbilt student health service, roughly equivalent amounts of typical influenzal disease were documented by virus isolation and total health service visits with both strains. however, considering that the college population was fully susceptible to the first introduction of h1n1 virus in ... | 1980 | 7457472 |