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Synthesis of viral proteins in polymorphonuclear leukocytes infected with influenza A virus
L F Cassidy1, D S Lyles, J S Abramson
1Department of Microbiology and Immunology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27103.
Abstract:
Various reports have indicated that infection of polymorphonuclear leukocytes (PMNL) with influenza virus causes depression of their metabolic and chemotactic responses, but the effect the PMNL has on the life cycle of influenza virus has not been well defined. The studies reported here were undertaken to determine whether influenza virus could replicate within PMNL. Virus-infected and uninfected PMNL were labeled with [35S]methionine and analyzed by gel electrophoresis and fluorography for detection of newly synthesized proteins. Both host- and virus-specific proteins were produced within PMNL. By using indirect immunofluorescence techniques combined with flow cytometry, the expression of newly synthesized viral antigens was detected in virus-infected PMNL. Plaque assays on supernatant fluid from infected PMNL showed that infectious progeny were not produced, indicating that influenza virus infection of PMNL is abortive.
Insights
Influenza virus infection of polymorphonuclear leukocytes (PMNL) leads to the production of viral proteins within these cells. However, infectious virus progeny are not generated, indicating an abortive infection cycle for influenza in PMNL.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Influenza virus infection of polymorphonuclear leukocytes (PMNL) is known to impair PMNL functions.
- The impact of PMNL on the influenza virus life cycle remains poorly understood.
Purpose of the Study:
- To investigate whether influenza virus can replicate within PMNL.
- To elucidate the interaction between influenza virus and PMNL at the molecular level.
Main Methods:
- PMNL were infected with influenza virus and metabolically labeled with [35S]methionine.
- Protein synthesis was analyzed using gel electrophoresis and fluorography.
- Viral antigen expression was assessed via indirect immunofluorescence and flow cytometry.
- Infectious progeny were quantified using plaque assays.
Main Results:
- Influenza virus-infected PMNL synthesized both host- and virus-specific proteins.
- Newly synthesized viral antigens were detected within infected PMNL.
- No infectious influenza virus progeny were released from infected PMNL.
Conclusions:
- Influenza virus infection of PMNL results in viral protein synthesis.
- The influenza virus life cycle is abortive within PMNL, as infectious progeny are not produced.