Analysis of HLA-DQ protein and peptide interaction in association to auto-immune mechanism of narcolepsy. (P5069)

Abstract Human narcolepsy is a sleep disorder characterized by excessive daytime sleepiness (EDS), cataplexy, and abnormalities of rapid eye movement (REM). Strong HLA class II association was determined where the narcoleptic individuals of diverse ethnic backgrounds share a specific HLA class II haplotype, DQA1*01:02-DQB1*06:02. It has been also reported that hypocretin in the CSF of narcoleptic patients are significantly decreased and that hypocretin producing cells are disrupted in patients’ brain. We hypothesized that hypocretin or other proteins specifically expressed in hypocretin producing cells in the hypothalamus, are presented by HLA-DQA1*01:02-DQB1*06:02, and induce activation of self-reactive T cells. To analyze the peptide-binding reperitore of HLA-DQA1*01:02-DQB1*06:02, we transduced murine fibroblast cells with HLA-DQA1*01:02-DQB1*06:02 (suscceptible), DQA1*01:03-DQB1*06:01 (resistant), DQA1*01:03-DQB1*06:03 (resistant), and DQA1*01:02-DQB1*06:04 (neutral) alleles by retrovirus-vectors and confirmed stable DQ proteins expression. Using these cell lysates we analyzed binding affinity of synthetic peptides designed for hypocretin-A, -B, and other proteins expressed in hypocretin producing cells.