+1 Frameshifting as a novel mechanism to generate a cryptic cytotoxic T lymphocyte epitope derived from human interleukin 10.
Recent data indicate that some cytotoxic T cells (CTLs) recognize so-called cryptic epitopes, encoded by nonprimary open reading frame (ORF) sequences or other nonclassical expression pathways. We describe here a novel mechanism leading to generation of a cryptic CTL epitope. We isolated from the synovial fluid of a patient suffering from a Reiter's syndrome an autoreactive T cell clone that recognized cellular IL-10 in the HLA-B*2705 context. The minimal IL-10 sequence corresponding to nucleotides 379-408 was shown to activate this clone, upon cotransfection into COS cells with the DNA encoding HLA-B*2705, but the synthetic peptide deduced from this sequence did not stimulate the clone. Using a site-directed mutagenesis approach, we found that this clone recognized a transframe epitope generated by an internal +1 frameshifting in the IL-10 sequence and so derived partly from ORF1, partly from ORF2. We defined that +1 frameshifting was induced by a specific heptamer sequence. These observations illustrate the variety of mechanisms leading to generation of cryptic epitopes and suggest that frameshifting in normal cellular genes may be more common than expected.
Saulquin
Xavier
X
INSERM U463, Institut de Biologie, Nantes Cedex 01, France.
Scotet
Emmanuel
E
Trautmann
Lydie
L
Peyrat
Marie-Alix
MA
Halary
Franck
F
Bonneville
Marc
M
Houssaint
Elisabeth
E
D000595:Amino Acid Sequence; D000818:Animals; D016918:Arthritis, Reactive / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D019556:COS Cells; D002999:Clone Cells; D018076:DNA, Complementary / Q000235:genetics; D000939:Epitopes / Q000235:genetics; D016368:Frameshift Mutation; D018965:Frameshifting, Ribosomal; D015235:HLA-B Antigens / Q000235:genetics; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics*; D008957:Models, Genetic; D018448:Models, Immunological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016366:Open Reading Frames; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014162:Transfection
D018076:DNA, Complementary; D000939:Epitopes; D015235:HLA-B Antigens; D016753:Interleukin-10