Final answer:
MHC proteins are crucial for the immune system, specifically for its ability to recognize self from non-self. They are presented by nucleated cells to T-cells, and abnormalities in MHC signaling can lead to autoimmune diseases.
Step-by-step explanation:
The correct option : b
The immune system employs MHC molecules to distinguish between self and non-self entities. MHC class I molecules are found on all nucleated cells and present peptides to T-cells, enabling the immune cells to monitor the health of these cells. If a cell is infected by a virus or becomes cancerous, MHC class I molecules will present abnormal peptides to T-cells, signaling an immune response. Meanwhile, MHC class II molecules are typically found on antigen-presenting cells and are involved in signaling between these cells and helper T-cells. These interactions are crucial for the immune response, leading to the activation of other immune cells and the production of antibodies.
A person who cannot produce MHC I molecules might develop an autoimmune disease, as their immune system would fail to recognize self cells correctly, potentially attacking healthy body cells.