Importin beta: a novel autoantigen in human autoimmunity identified by screening random peptide libraries on phage.
By screening random peptide libraries (RPLs) with sera of Type 1 diabetes (T1D) patients, we previously identified 5 disease-specific 'mimotopes' displayed on phages (phagotopes). We already characterised 1 phagotope (CH1p), as an epitope of human osteopontin, an autoantigen expressed within the somatostatin cells of human islets. In this paper, we report the characterization of the second phagotope, 195Dyn, by immunohistochemistry, Western Blotting and screening of a human islet cDNA library using rabbit anti-195Dyn antibodies. The 195Dyn mimotope was detected in human islets. The screening of a lambdagt11 cDNA library from human islets has identified a clone, which corresponded to human importin beta. ELISA detected autoantibodies against this protein in sera of around 60% of TD1 patients and in 30% of patients affected by other autoimmune diseases. In summary, RPLs technology proved again successful in identifying another novel autoantigen (importin beta), whose significance in the autoimmune process remains to be fully elucidated.
St Bartholomew's and the Royal London School of Medicine and Dentistry, Queen Mary College, London, UK.
Thomas O
TO
Ola
Paul A
PA
Biro
Mohammed I
MI
Hawa
Johnny
J
Ludvigsson
Mattia
M
Locatelli
Maria Ausiliatrice
MA
Puglisi
Gian Franco
GF
Bottazzo
Alessandra
A
Fierabracci
D000818:Animals; D001324:Autoantigens / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007150:Immunohistochemistry; D007515:Islets of Langerhans / Q000166:cytology / Q000276:immunology; D008969:Molecular Sequence Data; D019151:Peptide Library; D011817:Rabbits; D011863:Radioimmunoassay; D028961:beta Karyopherins / Q000235:genetics / Q000276:immunology*
D001324:Autoantigens; D019151:Peptide Library; D028961:beta Karyopherins