Question

The primary function of the class I and class II MHC molecules is:

• A. binding peptide antigens for recognition by antigen-specific receptors on T-cells.
• B. mediation of T-independent B-cell responses.
• C. helping in endocytosis of antigens by phagocytic cells.
• D. aid opsonization of foreign particle.

Hint:

MHC = "Display Case" for T-cell inspection.

Answer 1

The Correct Option is A

Step 1: Concept
T-cells cannot "see" antigens directly; they require antigens to be "presented" on MHC molecules.

Step 2: Meaning
MHC-I presents endogenous antigens to CD8+ T-cells, while MHC-II presents exogenous antigens to CD4+ T-cells.

Step 3: Analysis
The core structural role of MHC is to hold a processed peptide in its "groove" and display it on the cell surface so that the T-Cell Receptor (TCR) can recognize the complex.

Step 4: Conclusion
Their fundamental role is antigen presentation to T-cells. Final Answer: (A)