MIMM 214 Lecture Notes - Lecture 33: Mhc Restriction, Thymocyte, Peripheral Tolerance
10 May 2019
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Document Summary
Negative selection of thymocytes is mediated mostly by radio-sensitive bone marrow-derived cells. Thymocytes whose tcr shows too much reactivity for self p:mhc complexes are deleted (apoptosis) Aire is a protein that ensures expression of many tissue specific proteins in the thymus: source of peptides on which to test tolerance to self p:mhc complexes. Cortical epithelial cells: responsible for positive selection, not radio sensitive. Medullary epithelial cells: negative selection, originate from bone marrow precursors, radio sensitive. Answer: antigen is restricted to mhc a (cortical epithelial cells are resistant to radiation) Mhc restriction is to the mhc of the cortical epithelial cells: mediate positive selction. Tolerance is to the mhc of the medullary bone marrow derived cells: negative selection. Mouse t cells + ag: mhc x apc response = mhc restriction. Skin survival or rejection will show if tolerant. Even if not restricted to a certain mhc, there might still be response because of allorecognition.
