Anatomy and Physiology II Practice Test

Which cells are primarily involved in cell-mediated immunity?

1. T-cells, or T Lymphocytes

2. B-cells, or B Lymphocytes

3. Macrophages

4. Neutrophils

The correct answer is: T-cells, or T Lymphocytes

T-cells, or T Lymphocytes, play a critical role in cell-mediated immunity. This immune response is directly involved in the recognition and elimination of infected or cancerous cells. T-cells originate in the bone marrow but mature in the thymus, where they develop receptors that allow them to identify specific antigens presented by other cells. There are different types of T-cells, including helper T-cells and cytotoxic T-cells. Helper T-cells assist in activating other immune cells, while cytotoxic T-cells directly target and destroy cells that display foreign antigens, such as those infected by viruses. The primary function of cell-mediated immunity is to provide a tailored response to intracellular pathogens and tumor cells, which is distinctly different from the role of B-cells that are primarily responsible for antibody-mediated immunity (humoral immunity). While macrophages and neutrophils are important in the innate immune response, they do not specialize in the specific recognition of antigens and the subsequent targeted action against infected cells like T-cells do.