Cytotoxic T cell activity against the peptide, AYRARALEL, from Yo protein of patients with the HLA A24 or B27 supertype and paraneoplastic cerebellardegeneration

Objective; To determine a peptide that reacts with cytotoxic T cells (CTL) of patients with paraneoplastic cerebellar degeneration and anti-Yo antibod ies with either HLA A24 or B27 supertype. Method: We studied CTL activity o f four patients, three were HLA A24-positive and one did not have HLA A24 b ut had B27 supertype, After an incubation of mononuclear cells with or with out peptide and IL-2, CD8-rich fraction was prepared by treatment with Magn etic Cell Sorting system (MACS) twice. CTL activity was calculated by Cr-51 release from transfectant, ClRA* 2402 as target cells, The peptide-binding assay was examined by flow cytometry. Results: Two of three HLA A 24-posit ive patients demonstrated CTL activity against the Yo peptide, AYRARALEL. C TL activity was found to be 19.5% and 11.7% at the effector/target (E/T) ra tio of 23:1 and 11: 1, respectively. A patient who did not have HLA A24 but had A2 and B27 supertype possessed a CTL activity of 19.4% with 15:1 as E/ T ratio. The peptide could bind to HLA A* 2402 molecules but not to A* 0201 . Conclusions: We showed CTL activity in two of three Japanese patients wit h HLA A24 by using HLA A* 2402 transfectant cells as the target. In additio n. we identified the first Japanese patient who had B27 super-type, and sug gested that the same peptide, AYRARALEL, could be recognized by CTL in this patient. (C) 2001 Elsevier Science B.V. All rights reserved.