The central question addressed in the presentation will be “What do we know about (your) antibodies?”, highlighting how innovative techniques in mass spectrometry provide novel insights.
In our body we produce every day huge amounts of antibodies, of which many end up in circulation. Humans apparently can make about trillions of distinct antibody clones, all exhibiting a different sequence, recognizing distinct antigens. This huge number has so far refrained many from charting whole serum immunoglobulin (Ig), repertoires. We recently developed new LC-MS based antibody repertoire profiling methods for studying immunoglobulins in a quantitative manner. By now, we analyzed a variety of samples (sera, milk and saliva) from both healthy as well as diseased donors, allowing us to make some paradigm-shifting observations. Firstly, circulating Ig repertoires are much simpler than anticipated, dominated by just a few hundred clones. Second, the clonal repertoires are entirely unique for each donor. Next to focusing on these clonal repertoires we also used mass spectrometry to define new structural features of immunoglobulins, notably the co-occurrence of IgA monomers and dimers and CD5L as a new canonical component of serum IgM.