Question

In which of the step given in the diagram represent the exogenous presentation of antigen?

• A. Step 1
• B. Step 2
• C. Step 3
• D. None of the above

Answer 1

The correct option is C Step 3

MHC class I and class II molecules deliver short peptides to the cell surface allowing these peptides to be recognized by CD8+ and CD4+ T cells, respectively. Peptides originate from different sources endogenous or intracellular, for MHC class I and exogenous or extracellular for MHC class II. Also, cross-presentation takes place in which exogenous antigens can be presented by MHC class I molecules. Endogenous antigens can also be presented by MHC class II when they are degraded through autophagy. Thus the correct answer is option C.