CD80 and type 1 diabetes mellitus: Of special relevance, transgene expression of the co-stimulatory B7.1 molecule in β-cells has shown to represent a highly reproducible EAD induction model (Rajasalu et al. 2004; Rajasalu et al. 2010; Cobo-Vuilleumier et al. 2018), by inducing a rapid and consistent insulitis mimicking closely the aggressive immune attack occurring in younger children with type 1 diabetes (Craig et al. 2019).