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

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.

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Nonsense mutations affecting the lengths of the NS1 nonstructural proteins of influenza A virus isolates

Virology ◽

10.1016/0042-6822(83)90280-5 ◽

1983 ◽

Vol 128 (2) ◽

pp. 512-517 ◽

Cited By ~ 16

Author(s):

J.D. Parvin ◽

J.F. Young ◽

P. Palese

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Nonstructural Proteins ◽

Nonsense Mutations ◽

Virus Isolates

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Sulphatide binds to human and animal influenza A viruses, and inhibits the viral infection

Biochemical Journal ◽

10.1042/bj3180389 ◽

1996 ◽

Vol 318 (2) ◽

pp. 389-393 ◽

Cited By ~ 57

Author(s):

Takashi SUZUKI ◽

Ayako SOMETANI ◽

Yasuhiro YAMAZAKI ◽

Goh HORIIKE ◽

Yukiko MIZUTANI ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A Virus ◽

Influenza A ◽

Sialic Acid Residue ◽

Influenza A Viruses ◽

Human Influenza Virus ◽

Viral Binding ◽

Overlay Assay ◽

Virus Isolates ◽

Darby Canine Kidney

We found, by using a virus overlay assay, that influenza A virus isolates bind to sulphatide (HSO3-Galβ1 → 1´Cer), which has no sialic acid residue, and that the infection of Madin–Darby canine kidney cells with the human influenza virus A/Memphis/1/71 (H3N2) is inhibited by sulphatide. A/Memphis/1/71 (H3N2) causes obvious haemagglutination and low-pH haemolysis of asialoerythrocytes reconstituted with sulphatide. All influenza A virus isolates from the species of animals so far tested bound to sulphatide. The sulphatide-binding specificity of the isolates was different from the viral sialyl-linkage specificity. Influenza A virus isolates also bound to galactosyl ceramide (GalCer; Galβ1 → 1´Cer), as well as sulphatide, in the virus overlay assays. In contrast, the influenza virus did not bind to N-deacyl, a derivative of sulphatide, glucosyl ceramide or the other neutral glycolipids tested. These results indicate that the linkage of galactose, or sulphated galactose, to ceramide is important for viral binding.

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Immunologic studies on the influenza A virus nonstructural protein NS1.

Journal of Experimental Medicine ◽

10.1084/jem.156.1.243 ◽

1982 ◽

Vol 156 (1) ◽

pp. 243-254 ◽

Cited By ~ 10

Author(s):

M W Shaw ◽

E W Lamon ◽

R W Compans

Keyword(s):

Influenza Virus ◽

Influenza A Virus ◽

Influenza A ◽

Nonstructural Protein ◽

Antigenic Drift ◽

Ns1 Protein ◽

Influenza A Viruses ◽

Cytoplasmic Inclusions ◽

Infected Cells ◽

Virus Isolates

We purified the major influenza virus nonstructural protein, designated NS1, from cytoplasmic inclusions that were solubilized and used to raise antisera in rabbits. One of the antisera was found to be specific for NS1 by complement fixation tests and analyses of immune precipitates. Antiserum to NS1 isolated from cells infected with A/WSN/33 virus specifically precipitated NS1 from extracts of cells infected with seven distinct isolates of influenza A virus representing five different antigenic subtypes. These included A/WSN/33, A/PR/8/34, A/FW/5/50, A/USSR/90/77, A/RI/5+/57, A/Victoria/3/75, and A/Swine /1977/31; however, NS1 from cells infected with B/Lee/40 virus was not precipitated. Radioimmunoassays using radioiodinated NS1 protein from A/WSN virus-infected cells and unlabeled cytoplasmic extracts of cells infected with various strains of influenza virus as competitors indicated significant antigenic cross-reactivities for the NS1 proteins of all influenza A viruses tested. The results suggest a gradual antigenic drift over the 45 yr separating the earliest and most recent virus isolates examined. Thus, compared with the virion neuraminidase and hemagglutinin antigens, NS1 appears to be highly conserved in different influenza A virus isolates.

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