MCQ IN MEDICINE

Detailed explanation-1: -Cytotoxic T-cells kill cells infected with viruses and bacteria, and they also destroy tumor cells. Helper T-cells: Helper T-cells are also called CD4+ cells because they have a CD4 receptor on their membranes.

Detailed explanation-2: -Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.