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Rapid subtyping of influenza A virus isolates by membrane fluorescence
Abstract:
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.
Insights
Rapidly identify influenza A virus strains using live cell membrane fluorescence. This technique accurately distinguishes between H3N2 and H1N1 subtypes, offering faster results than traditional methods.
Area of Science:
- Virology
- Immunology
- Diagnostic Microbiology
Background:
- Influenza A virus surveillance is critical for public health.
- Accurate and rapid identification of circulating influenza A virus subtypes (H3N2 and H1N1) is essential for effective management and treatment.
- Traditional diagnostic methods can be time-consuming.
Purpose of the Study:
- To evaluate the efficacy of indirect immunofluorescence technique for specific identification of influenza A virus serotypes.
- To compare the speed and accuracy of immunofluorescence with hemagglutination inhibition for influenza A virus identification.
Main Methods:
- Primary monkey kidney cells were infected with influenza A viruses.
- Surface antigens of infected cells were stained using indirect immunofluorescence with specific anti-H3N2 and anti-H1N1 antisera.
- Clinical specimens were tested, and results compared with hemagglutination inhibition.
Main Results:
- The immunofluorescence technique correctly identified 45 of 48 influenza A H3N2 and 24 of 29 H1N1 specimens.
- H3N2 strains were distinguishable from H1N1 strains, but not from each other.
- The average identification time was 4 days, compared to 7 days for hemagglutination inhibition, with one false positive among non-influenza isolates.
Conclusions:
- Live cell membrane immunofluorescence is a simple, rapid, and accurate method for identifying and grouping influenza A viruses.
- This technique offers a significant time advantage over hemagglutination inhibition.
- It shows high specificity and sensitivity for differentiating major influenza A subtypes.