INS and type 1 diabetes mellitus: T1D susceptibility in BB rats extends beyond Iddm1 and Iddm2, as MHC-matched Wistar-Furth (WF), PVG.R8, and Fischer (F344) rats are not susceptible to viral induced T1D and lymphopenic Gimap5-/- F344 rats do not develop spontaneous diabetes [16, 17].