Peptide ASQ

EAE has been successfully treated with the immunodominant epitope of MBP, Ac1-11, as well as analogues in which position four is changed from the native lysine to an alanine (Ac1-11[4A]) or tyrosine (Ac1-11[4Y]). Ac1-11[4A] and Ac1-11[4Y] bind to the MHC with ∼50 and 1,500 times higher affinity than does Ac1-11, and both peptides stimulate most Ac1-11–specific T cells more efficiently than does Ac1-11. The affinities of these peptides for I-Au correlate with the half-lives of each of the peptides complexed to I-Aᵘ; Ac1-11/I-Aᵘ has an immeasurably short half-life, Ac1-11[4A] has a half-life of ∼10 min, and Ac1-11[4Y]/I-Au can be detected for as long as 10 h. The efficacy of treatment of EAE with these three peptides correlates with the affinity of the peptides for I-Aᵘ. The mechanism of this treatment may be due to anergy, deletion, a switch in Th subset, or a combination of these phenomena.