$T_c$ cells recognize epitopes only when the latter are held by

• A. MHC proteins.
• B. B cells.
• C. Interleukin-2.
• D. Granzyme.

Answer: (A)

Verified step by step guidance

1. Understand the role of Tc (cytotoxic T) cells in the immune system. These cells are responsible for identifying and destroying infected or cancerous cells.
2. Learn about epitopes, which are specific parts of antigens that immune cells recognize and bind to. Tc cells require these epitopes to be presented in a specific way to initiate an immune response.
3. Explore the function of MHC (Major Histocompatibility Complex) proteins. These proteins are crucial for presenting epitopes on the surface of cells, allowing Tc cells to recognize them.
4. Differentiate between the types of MHC proteins: MHC class I and MHC class II. Tc cells specifically interact with MHC class I proteins, which present epitopes from intracellular pathogens.
5. Conclude that Tc cells recognize epitopes only when they are presented by MHC proteins, as this interaction is essential for the activation and function of Tc cells in the immune response.