Question

This year’s flu, which is dominated by H3N2 (an influenza A strain), has caused severe morbidity and mortality. The virus is usually spread through contact with aerosols and droplets, and introduced into epithelial cells of the respiratory tract. Both you and your wife caught flu two-three week ago, and had miserable time with similar symptoms although you got sick first and then she came down 1 week later. In addition to experiencing local symptoms, like sore throat and nasal congestion, you two also had systemic symptoms, such as fever and muscle pain. Many of these symptoms likely reflect ongoing immune reactions. Ten days later, you recovered completely. With the knowledge just learned in the past three lectures, please describe how your immune system worked to fight off the infection, what immunological events account for your local and systemic symptoms?

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 own nasal swap or nasal isolate of your wife (assuming you could collect these cells). These epithelial cells were infected in a test tube to serve as targets (i.e., target/H3N2) for analyzing activity of your CD8 cells. Specifically, you mixed your CD8+ cells with either your own epithelial cells (target-A) or epithelial cells derived from your wife (target-B), illustrated as below, would these target cells be killed by your CD8 cells and why?

1.CD8+ cells + Target-A/H3N2

2.CD8+ cells + Target-B/H3N2

Answer 1

Both these targets are likked by the cytotoxic T-cells (CTL) which is known for killing or resposive to heretosubtypic immunity. This is because , antigen presenting cells ( say MHC proteins, macrophage , dendrites) process the viral proteins (H3N2) to the M1 protein to the CTL which CTL recognize and kill that cell irregarding of target epethilial cells.The processing peotein is same for both the target cell because both target cell has same viral protein H3N2 and same processing and presentation will be done to CTL.