Final answer:
In cell-mediated immunity, four types of cells are involved: T-helper cells, T-suppressor cells, T-cytotoxic cells, and T-delayed type hypersensitive cells; they aid in immune activation, regulation, direct destruction of infected cells, and mediate hypersensitive reactions respectively.
Step-by-step explanation:
Cells Involved in Cell-Mediated Immunity
The four types of cells that play a crucial role in cell-mediated immunity are:
T-helper cells (Th cells or CD4+ T cells): These cells assist in the activation and differentiation of B cells and other immune cells.
T-suppressor cells (Treg cells or regulatory T cells): They regulate the immune response by suppressing the activity of B cells and other T cells to prevent an overactive immune response.
T-cytotoxic cells (Tc cells or CD8+ T cells): These cells are responsible for directly killing infected host cells, particularly those harbouring viruses.
T-delayed type hypersensitive cells (TDTH cells): Are part of the adaptive immune response and are involved in delayed hypersensitive reactions such as allergic contact dermatitis.
These cells work together to recognize and eliminate cells infected by pathogens, prevent autoimmunity, and mediate hypersensitive responses.