This year’s flu, which is dominated by H3N2 (an influenza Astrain), has caused severe morbidity and mortality. The virus isusually spread through contact with aerosols and droplets, andintroduced into epithelial cells of the respiratory tract. Both youand your wife caught flu two-three week ago, and had miserable timewith similar symptoms although you got sick first and then she camedown 1 week later. In addition to experiencing local symptoms, likesore throat and nasal congestion, you two also had systemicsymptoms, such as fever and muscle pain. Many of these symptomslikely reflect ongoing immune reactions. Ten days later, yourecovered completely. With the knowledge just learned in the pastthree lectures, please describe how your immune system worked tofight off the infection.

To determine if you developed virus-specific T cell immunity,you collected CD8+ T cells from your own blood (not your wife’s)and expanded some epithelial cells isolated either from your ownnasal swap or nasal isolate of your wife (assuming you couldcollect these cells). These epithelial cells were infected ina test tube to serve as targets (i.e., target/H3N2) for analyzingactivity of your CD8 cells. Specifically, you mixed your CD8+ cellswith either your own epithelial cells (target-A) or epithelialcells derived from your wife (target-B), illustrated as below,would these target cells be killed by your CD8 cells andwhy?

1.CD8+ cells +Target-A/H3N2

2.CD8+ cells +Target-B/H3N2