To prevent immunopathology, differentiation of CD8+ T cells is tightly controlled by inhibitory receptors such as CTLA-4. Project B 14, in collaboration with B 16, identified by iTRAQ mass spectrometry novel signal transduction pathways downstream of CTLA-4 that will be further characterized in the 3rd funding period. In this respect, B 14 will connect changes in cellular metabolism with altered T cell functions. The role of CTLA-4-mediated TCF-1 regulation in memory formation will be analyzed in a Listeria infection model in collaboration with A 05. Furthermore, B 14 will analyze the impact of CTLA-4 on JAML in the context of co-stimulation and adhesion in collaboration with B 08 and B 12.