Question

Arrange the steps in antigen processing by endocytic pathway in correct order :
A. Recognition by CD4\(^+\) T cells
B. Antigen uptake by APC
C. Transport of MHC-peptide complex to cell surface
D. Peptide loading onto MHC class II molecule
E. Fusion of phagosome with lysosome
Choose the correct answer from the options given below :

• A. \(A, B, C, D, E\)
• B. \(B, E, D, C, A\)
• C. \(E, A, D, B, C\)
• D. \(C, E, A, D, B\)

Hint:

Remember: \[ \text{Exogenous antigen} \rightarrow \text{MHC class II} \rightarrow CD4^+ \text{ T cells} \] while: \[ \text{Endogenous antigen} \rightarrow \text{MHC class I} \rightarrow CD8^+ \text{ T cells} \]
• APCs process extracellular antigens through the endocytic pathway.

Answer 1

The Correct Option is B