Which are correctly matched?

• A. cytotoxic T cells: activated by antigens bound to MHC I
• B. helper T cells: recognize virus-infected cells
• C. B cells: suppress the immune response once the foreign antigen has been cleared from the body
• D. regulatory T cells: make antibodies

Answer: (A)

Verified step by step guidance

1. Understand the role of cytotoxic T cells: These cells are part of the adaptive immune system and are responsible for killing virus-infected cells and cancer cells. They are activated by antigens presented on MHC I molecules, which are found on all nucleated cells.
2. Clarify the function of helper T cells: Helper T cells do not directly recognize virus-infected cells. Instead, they assist other cells in the immune response by recognizing antigens presented by MHC II molecules on antigen-presenting cells, such as dendritic cells and macrophages.
3. Examine the role of B cells: B cells are responsible for producing antibodies, not suppressing the immune response. Once activated by helper T cells, B cells differentiate into plasma cells that secrete antibodies specific to the antigen.
4. Explore the function of regulatory T cells: Regulatory T cells are involved in suppressing the immune response to prevent overactivity that could lead to autoimmune diseases. They do not make antibodies; this is the role of B cells.
5. Match the correct functions: Cytotoxic T cells are correctly matched with activation by antigens bound to MHC I. Helper T cells, B cells, and regulatory T cells are incorrectly matched in the given options.