Which statement is FALSE about cytotoxic T cells?

• A. They stimulate B cells.
• B. They destroy virus-infected cells.
• C. They recognize MHC I bound antigens on APCs.
• D. They induce apoptosis in infected cells.

Answer: (A)

Verified step by step guidance

1. Understand the role of cytotoxic T cells in the immune system. Cytotoxic T cells, also known as CD8+ T cells, are primarily responsible for directly killing infected cells, particularly those infected by viruses.
2. Review the function of B cells in the immune response. B cells are responsible for producing antibodies and are activated by helper T cells (CD4+ T cells), not cytotoxic T cells.
3. Examine the interaction between cytotoxic T cells and MHC I molecules. Cytotoxic T cells recognize antigens presented by MHC I molecules, which are found on all nucleated cells, including antigen-presenting cells (APCs).
4. Consider the mechanism of apoptosis induction by cytotoxic T cells. These cells release perforin and granzymes to induce apoptosis in infected cells, effectively eliminating the threat.
5. Identify the false statement by comparing the functions of cytotoxic T cells with the options provided. The statement 'They stimulate B cells' is false because cytotoxic T cells do not directly stimulate B cells; this is the role of helper T cells.