AH 3121 Study Guide - Midterm Guide: Epitope, Microorganism, T-Cell Receptor
Document Summary
B cell receptors recognize polysaccharides, lipids, and proteins. Cytokines & heat shock proteins belong to class iii mhcs. Mhc molecules that are not bound to peptides are degraded. Mhc:foreign peptide complexes are the only complexes that t cells on patrol respond to. All nucleated cells can perform antigen presentation. Each mhc molecule can present many different peptides (broad specificity). Mhc restriction of t cells occurs in the thymus. Peptide binding clefts allow for the anchoring of peptides. The diversity of mhc molecules makes it much more likely for individuals with divergent haplotypes to survive epidemics. The mhc:peptide bond is not of high affinity. In mhc:peptide bonds each mhc molecule can be bound to only 1 peptide at a time and that peptide remains bound for several hours or days; only peptide-loaded mhc molecules are expressed on cell surfaces. Mhc class ii molecules can accommodate the biggest peptide fragments.
