Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: The viral cytotoxic T lymphocyte (CTL) epitope peptides presented by classical MHC-I 13 molecules require the assembly of a peptide-MHC-I-β2m (aka pMHC-I) trimolecular complex 14 for TCR recognition, which is the critical activation link for triggering antiviral T cell immunity. 15 Ursidae includes 5 genera and 8 species; however, research on T cell immunology in this family, 16 especially structural immunology, is lacking. In this study, the structure of the key trimolecular 17 complex pMHC-1 (aka pAime-128), which binds a peptide from canine distemper virus, was solved 18 for the first time using giant panda as a representative species of Ursidae. The structural 19 characteristics of the giant panda pMHC-I complex, including the unique pockets in the 20 peptide-binding groove (PBG), were analyzed in detail. Comparing the panda pMHC-I to others 21 in the bear family and extending the comparison to other mammals revealed distinct features. 22 Spriggs H, Dear PH, Briggs AW. 2008. Mitochondrial genomes reveal an explosive radiation 469 of extinct and extant bears near the Miocene-Pliocene boundary. Bmc Evolutionary Biology 470 8:220-220. 471 22. et al. 2009. The sequence and de novo assembly of the 476 giant panda genome. Nature 463:311. 477 Pan HJ, Wan QH, Fang SG. 2008. Molecular characterization of major histocompatibility 478 complex class I genes from the giant panda (Ailuropoda melanoleuca). Immunogenetics

Crystal structure of the giant panda MHC class I complex: first insights into the viral 1 peptide presentation profile in the bear family 2