T-cell responses against the pathogenic MOG 91–108 epitope are lacking in DA rats immunized with rHuMOGPBS. MOG-specific T-cell responses were measured at day 12 p.i. by IFN-γ ELISPOT (data are represented as mean values ± S.E.). Asterisks indicate significance of difference with rHuMOGREF group for after restimulation with the antigen indicated on the x axis (rHuMOGPBS, n = 6; rHuMOGAC, n = 3; rHuMOGREF, n = 5; *, p < 0.05; **, p < 0.001;).