Oral Presentation The 43rd Lorne Conference on Protein Structure and Function 2018

T cell receptors have some more tricks up their sleeves. (#16)

Stephanie Gras 1
  1. Monash University, Clayton, VIC, Australia

Our immune system comprises an army of diverse cell types designed to defend our body against infections. These immune cells specifically recognise invaders (pathogens) and, once activated, elicit a targeted attack to eliminate the infection. Within the army of immune cells are T cells equipped with receptors (TCRs). TCRs recognise a fragment of a pathogen (i.e., bits of peptides, lipids, or small molecules) that are presented by a host-specific major histocompatibility complex (MHC) molecule found on the surface of antigen-presenting cells (APCs). This interaction between a TCR and an antigen (i.e., a pathogen fragment) bound to an MHC molecule is critical, as it is the first event in the process of T cell activation that will, in turn, dictate the fate of an infection.


Over the last 20 years, the field of T cell immunology has greatly benefited from structural biology. The first structure of a TCR recognising an antigen bound by an MHC molecule was solved in 1996. Since then, numerous co-crystal structures of TCRs in complex with different MHC molecules bearing diverse antigens have been reported, providing us with a snapshot of this critical interaction. Studies linking structural and functional information about T cell recognition have also been highly informative. From the structures available, some common features of the molecular basis of antigen recognition by T cells have emerged. However, newly identified T cells do not follow the previous dogma, and have made us rethink the molecular basis of TCR recognition.

Using X-ray crystallography to determine the specific interaction between the TCR and the antigens-MHC complexes, revealed some novel modes of antigen recognition by T cells. Those discoveries have opened up new avenues in the field of T cell immunology, showing that T cells still have a few more tricks up their sleeves in the fight against infection.