Anatomy and Physiology II Practice Test

What is the primary function of cytotoxic T-cells?

1. Produce antibodies

2. Kill infected cells

3. Enhance B-cell activity

4. Promote inflammation

The correct answer is: Kill infected cells

Cytotoxic T-cells, also known as CD8+ T cells, play a crucial role in the immune response by directly targeting and killing infected cells, particularly those infected with viruses. These cells recognize specific antigens presented by infected cells on major histocompatibility complex (MHC) class I molecules. Once they identify a target cell, cytotoxic T-cells release perforin and granzymes, which are substances that create pores in the cell membrane of the infected cell and induce apoptosis (programmed cell death). This ability to directly eliminate cells harboring pathogens is vital for controlling infections and preventing the spread of disease within the body. In contrast, the roles of other options are distinct and do not align with the primary function of cytotoxic T-cells. Antibody production is primarily carried out by B-cells, enhancing B-cell activity involves help from helper T-cells, and promoting inflammation is typically a function of other immune cells and cytokines rather than cytotoxic T-cells. This specificity of function underscores the importance of cytotoxic T-cells in the adaptive immune response.