MIMM 214 Lecture 13: Linking Innate and Adaptive Immunity IV: Antigen Processing - MHC I & MHC II
8 Feb 2017
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Figure: different visual of the same process: the same proteins involved, some interactions, you are a scientist studying macrophage biology. You generated a mutant macrophage cell line that is unable to present antigen to cd8+ t cells. Your experimental data fails to detect mhc molecules in proximity to tap. Answer: probably mutation of tapasin chaperone protein, tap, mhc i itself, etc. The problem will be caused by the involved proteins. Two pathways merge: peptides are generated from internalized antigens in endocytic vesicles, particles are taken in within endosomes, endosomes are fused with lysosome, contents are degraded. Simultaneously, mhc class ii molecules are produced and exported from the er in vesicles to the cell membrane. Peptides are generated: endocytosed antigen in a vesicle that fuses with a lysosome, causes acidification of the endocytic compartment that degrades the antigen into peptide fragments. Mhc ii molecules are produced: mhc-ii formed in er. Invariant chain (ii) binds to peptide groove of inactive mhc-ii.
