Which one of the following statements is true with regard to processing and presentation ofprotein antigens?
- In the class II MHC pathway. protein antigens in the cytosol are processed byproteasomes
- In the class I MHC pathway. extracellular protein antigens are endoc'osed into vesiclesand processed
- In the class I MHC' pathway. transporter associated antigen processing (TAP) protein isrequired for translocating processed peptides generated in the cytosol
- Invariant chain in endoplasmic reticulum is involved in transport of peptides and loadingof class I MHC