MIMM 214 Lecture Notes - Lecture 16: Pd-L1, Autocrine Signalling, Il-2 Receptor

• School: McGill University
• Department: Microbiology & Immunology
• Course: MIMM 214
• Professor: Claire Trottier

Document Summary

Signal 2 - survival: costimulatory signals are required for optimal t-cell activation and proliferation, positive costimulatory receptors - facilitate activation, cd28, negative costimulatory receptors - help turn activation off, ctla-4, pd-1. T cell activation: costimulatory ligands and receptors. Ligands on apc: cd80 (b7. 1, cd86 (b7. 2, receptor on t cell --> cd28. Found on all na ve t cells: expressed constitutively under resting conditions, binds both b7. 1 (cd80) and b7. 2 (cd86) - both expressed by activated apcs, costimulatory signals are required for optimal t-cell activation and proliferation. Triggers phosphorylation of cd28 receptor by a kinase: binding to b7. 1 or b7. 2, recruitment of another kinase through sh3 domain, additional signaling. In the absence of costimulation, t cells become anergic: clonal anergy results, anergic t cell can no longer respond to stimulation. Figure: (a) the apc does not express costimulatory ligands (cd80/86), but it is still presenting to a t cell.