Bronge and colleagues set out to identify previously unknown T cell autoantigens, as pathological T cells are known to play a significant role in inflammation during MS (multiple sclerosis). Because of its sensitivity, the authors chose FluoroSpot for the screening. The screening was performed with recombinant fragments of proteins expressed in the central nervous system. (These fragments are PrESTs and were initially selected to represent unique epitopes for the human protein atlas project.) The selected antigens were coupled onto phagocytable particles and used to stimulate donors’ PBMCs in the screening with IFN-γ/IL-22/IL-17A FluoroSpot.
Next, the findings from the explorative screening were validated using a recombinant version of the full-length autoantigens in a similar FluoroSpot setup. The four new MS autoantigens were additionally validated in a comparable experiment using flow cytometry. Ultimately, the autoantigens’ immunogenicity and potential to induce encephalitis were confirmed by immunization in mice.
The authors’ methodological setup has the potential of semi-high throughput screening, testing many antigens in parallel. However, one should keep in mind that uncovering very rare T cell epitopes remains challenging. Revealing a patient’s autoantigen profile is the starting point for any future personalized treatments.