Antibodies are one of our key defences against infectious disease. Our immune systems can make billions of antibody variants to counter the extremely diverse components of infectious organisms that we encounter. With the advent of next-generation sequencing, it is now possible to fully characterise the composition of antibody and T-cell receptor (TCR) sequence repertoires. Particular clones of sequences are expanded during infections according to the antigens encountered, so these sequencing techniques provide a snapshot of how an individual responds to an infectious disease or provide a 'fingerprint' indicating how they responded to past infections.
By combining repertoire sequencing with other molecular methods, we study what makes people immune to infectious diseases. Sometimes the immune system can cause disease itself - we are also analysing the antibodies generated in autoimmune conditions to understand why the immune system can go wrong and how we can prevent it.