Some latest achievements in immunology research

Liu, Wei

The T cell pathways play a central role in regulating the immune response. Accumulating evidences indicate that the interaction of T-cell receptor (TCR) with antigenic peptide/major histocompatibility complex (MHC) alone is not sufficient to drive the activation of naive T cells leading to optimal immue responses [14] . A group of "costimulatory molecules" present on cell surface have been identified to actively suppress T cell responses in the presence of TCR signal [15] . Wang et al. [16] , who discovered various costimulatory and coinhibitory molecules in T cell activation, reviewed the recent studies on two major families involved in T cell costimulation and regulation of adaptive immunity from perspective of structural immunology. The most extensively investigated receptors expressed on T cells and ligands expressed on the antigen-presenting cells or peripheral tissues include the members of the B7/CD28 and tumor-necrosis factor (TNF)/TNFR families. Molecular polymerization state and module organization of all these receptors and ligands are schematically represented in this review chapter, with detailed description of domain structures. Physiological function of each family member and therapeutic application of the B7-CD28/CTLA-4 and the B7-H1/B7-DC/PD-1 pathways are well summarized as well.