MHC Class 2 (Exogenous Antigen)

MHC class 2 every cell that has MHC class 2 ALSO has MHC class | 50 every cell that is capable of exogenous antigen presentation is ALSO Capable of endogenous antigen presentation MHC class 2 Presents Exogenous Antigen MIC extracellular MHC class 2 presents exogenous peptide (obtained from the endocytic pathway) to CD4" helper T-col 3 types of antigen presenting cells: the dendritle cell is the ONLY cell that con activate a naive T-cell occurs through antigen presentatie innitiates adaptive immunity. MHC class 2 is not as picky as MHC class I How does MHC class 2 arrive in the cytoplasm unbound? The Invariant Chain! ↓ Solves 2 problems 1) ensures that MHC class 2 doesn't bind endogenous proteins 2) ensures that MHC class 2 is correctly trafficked to the endosome via phagocytosis, pinocytosis, receptor-mediated endocytosis Cathin-csand Antigen HLIDM CUP ALC K4358 CLP: cleaved section of the invariant chain that binds to MHC class 2 to block binding of peptides in vesicles HLA-DM: removes CLP which allows peptide to bind Antigen Presentation: Naive T cell 1 TCR signaling APC antigen presentation to a naive helper T-cell! Gene expression Co-stimulatory Interactise Autocrine Paracrine Cytokine signaling Engman pathway Review MHC class 1 and 2: Rough Peptide TA Endocytic pathway Digested Invariant chain degradering CLP MHC