91401 Lecture Notes - Lecture 8: Ctla-4, Cd28, Cd86
Document Summary
Immunity t cell regulation: t cell activation (signal 1) can be inhibited by dephosphorylation, co-stimulation (signal 2) can be inhibited by ctla-4 b7. 1 = cd80 b7. 2 = Cd86: cytokine signalling can be terminated by negative feedback and/or dephosphorylation of receptor complexes, apoptosis also has an important role in terminating t cell responses after clearance of pathogen. Ctla-4, inhibitor receptor that competes with cd28 for b7 binding: costimulatory signal (signal 2) can be modified by additional co- stimulatory pathways; Ctla4 (cd152) is a structural analogue of cd28. Binds b7 (b7. 1/b7. 2 = cd80/cd86) with 20x more avidity than cd28. Delivers inhibitory signal to activated t cell to make progeny less responsive to apc stimulation and limits il-2 production. Host defence peptides (hdps: certain antimicrobial peptides (amps) also have immune regulatory properties. These are short, cationic and also known as host defence peptides (hdps: e. g. Ll-37, catholicising which modulates immune responses according to environmental needs.
