Final answer:
Cytotoxic T cells respond to a flu virus infection by recognizing and destroying infected cells through clonal expansion, and by using perforin and granzymes to induce apoptosis, thereby preventing viral replication.
Step-by-step explanation:
When you are infected with the latest strain of the flu virus, your cytotoxic T cells (Tc) play a crucial role in your immune response. These cells specialize in recognizing and destroying cells infected with viruses. Clonal expansion allows for a rapid increase in the number of cytotoxic T cells that can target the virus, and each Tc cell has the ability to kill multiple infected cells. The process begins with the activation of these Tc cells upon detecting viral antigens presented on the surface of infected cells by MHC I molecules. Once activated, cytotoxic T cells release perforin and granzymes, which form pores in the cell membrane of the infected cell and induce apoptosis. This targeted killing of infected cells before the viruses can replicate prevents the spread of the infection and is a key factor to overcoming the viral disease.