Diabetes is predicted by the β cell level of autoantigen

Two novel transgenic (Tg) strains were created expressing hen egg-white lysozyme (HEL) in a pancreas-specific fashion. RmHP.111 mice had levels of HEL per cell similar to that of the established ILK-3 strain, while RmHP.117 mice had 10-fold lower levels (50,000 molecules per cell). When bred to 3A9 TCM Tg mice, negative selection occurred equally in all three double-Tg combinations, yet only ILK-3 × 3A9 and RmHP.111 × 3A9 mice became diabetic. Additionally, activated 3A9 cells readily transferred diabetes into ILK-3 or RmHP.111 mice, but only marginally into the RmHP.117 strain. In the peripancreatic lymph node, division of naive 3A9 cells was similar between RmHP.111 and RmHP.117 strains, but pancreatic APCs from RmHP.111 × 3A9 mice stimulated HEL-reactive cells to a much greater degree than those from RmHP.117 × 3A9 mice. In this model, diabetes was dependent upon both initial priming in the peripancreatic lymph node and subsequent presentation in the pancreas, with disease incidence predicted by the β cell level of autoantigen.