Final answer:
Cytotoxic T cells, or CD8+ T cells, are crucial in eliminating infected cells by inducing apoptosis, especially during viral infections. They undergo clonal expansion upon activation to produce effector and memory T cells, contributing to both immediate and future immune responses against the pathogens. correct answer is A .
Step-by-step explanation:
Cytotoxic T cells (Tc or CTLs), also known as CD8+ T cells, are a critical component of the adaptive immune system. They play a vital role in the cell-mediated immune defense by identifying and destroying cells infected by pathogens, particularly viruses, which evade the extracellular reach of antibodies by replicating within host cells. The presence of viral peptides presented on MHC Class I molecules on the surface of infected cells triggers the activation of these T cells.
Upon activation, cytotoxic T cells undergo clonal proliferation, creating a large number of effector cells that target and eradicate infected cells through apoptosis. There is a period of time required to generate a sufficient population of clonal effector T cells; hence, the adaptive response is slower than the innate immune response.