Microbiology MCAT Practice Question
A 34-year-old woman presents with a 5-day history of fever, myalgias, and cough consistent with acute viral respiratory infection. A nasopharyngeal swab is positive for influenza A virus. Researchers studying her immune response discover that the influenza virus she is infected with produces a nonstructural protein (NS1) that binds to and prevents phosphorylation of STAT1 and STAT2 transcription factors. These patients typically experience higher viral loads and more prolonged illness compared to those infected with wild-type influenza. Which of the following best explains the mechanism by which NS1-mediated blockade of STAT1/STAT2 signaling contributes to increased viral replication?
Answer choices
- AIncreased production of type I interferon (IFN-α/β) due to unopposed JAK kinase activation
- BDecreased expression of interferon-stimulated genes (ISGs) encoding antiviral effectors such as PKR and MxACorrect answer
- CEnhanced maturation and activation of dendritic cells leading to stronger adaptive immune responses
- DAccelerated apoptosis of infected epithelial cells through caspase-3 activation
- EUpregulation of viral entry receptors on the surface of uninfected respiratory epithelial cells
- FIncreased recruitment of neutrophils to the respiratory tract through CXCL8 production
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