Antigen Processing & Presentation

1. Antigen Processing & Presentation

6. Experimental demonstration of self-MHC restriction of TH cells. Peritoneal exudate cells from strain 2, strain 13, or (2 13) F1 guinea pigs were incubated in plastic Petri dishes, allowing enrichment of macrophages, which are adherent cells. The peritoneal macrophages were then incubated with antigen. These “antigen-pulsed” macrophages were incubated in vitro with T cells from strain 2, strain13, or (2 13) F1 guinea pigs, and the degree of T-cell proliferation was assessed. The results indicated that TH cells could proliferate only in response to antigen presented by macrophages that shared MHC alleles.

13. synthesize normal levels of class I ἃ-chains and β2-microglobulin, but Express only 5% of MHC-I • Townsend et. al., discovered, RMA-S mutant cell line Concluded restored their level of membrane-associated class I MHC molecules to normal. “feeding” these cells with peptides The ability to restore expression of class I MHC molecules on the membrane by feeding the cells Pre-digested peptides suggested that the RMA-S cell line might have a defect in peptide transport • peptides might be required to stabilize the interaction between the class I ἃ-chains and β2-microglobulin.

14. the defect in expression of MHC in the RMA-S cell line occurred due-------------- problem in the protein that transports peptides from the cytoplasm to the RER, where class I molecules are synthesized

15. The transporter protein, designated as TAP (transporter associated with antigen processing)

23. invariant chain (Ii, CD74). + preventing any endogenously derived peptides Interact with Peptide cleft subsequent routing of class II molecules to the endocytic processing pathway from the trans-Golgi network. also appears to be involved in the folding of the class II