Question

Endogenous antigens are processed and presented to the T-cells by

• A. MHC I.
• B. MHC II.
• C. Mast cells.
• D. None of the above.

Answer 1

The correct option is A MHC I.

A- Antigen presentation is mediated by MHC class I and class II molecules found mainly on the surface of APCs (antigen presenting cell). MHC I & II molecules are similar functionally as both deliver short peptides to the cell surface and allow them to be recognized by CD8+ (cytotoxic) & CD4+ (helper cells) respectively. The difference is that peptides orginate from different sources : endogenous or intracellular for MHC class I, and exogenous or extracellular for MHC class II.

So, the correct answer is 'MHC I'