Final answer:
Cytotoxic T cells are important components of the adaptive immune system, attacking and destroying infected host cells. They play a crucial role in protecting against viral infections because viruses replicate within cells, shielding them from antibodies. Once activated, cytotoxic T cells create a clone of cells with specific receptors that identify infected host cells.
Step-by-step explanation:
Cytotoxic T cells (TC) are the key component of the cell-mediated part of the adaptive immune system and attack and destroy infected cells. Tc cells are particularly important in protecting against viral infections; this is because viruses replicate within cells where they are shielded from extracellular contact with circulating antibodies. Once activated, the Tc creates a large clone of cells with one specific set of cell-surface receptors, as in the case with proliferation of activated B cells. As with B cells, the clone includes active Tc cells and inactive memory Tc cells. The resulting active Tc cells then identify infected host cells. Because of the time required to generate a population of clonal T and B cells, there is a delay in the adaptive immune response compared to the innate immune response.