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Proceedings of the 31 st European Peptide SymposiumMichal Lebl, Morten Meldal, Knud J. Jensen, Thomas Hoeg-Jensen (Editors)European Peptide Society, 2010B-Cell Epitope Mapping of Immunodominant Proteins inPemphigus Vulgaris: Prediction, Synthesis, andImmunoserological EvaluationHajnalka Szabados 1 , Szilvia Bősze 1 , Antal Blazsek 2 , Pálma Silló 2 ,Sarolta Kárpáti 2 , Ferenc Hudecz 1,3 , and Katalin Uray 11 Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös LorándUniversity, Budapest, H-1117, Hungary; 2 Department of Dermato-Venereology and SkinOncology, Semmelweis University, Budapest, Hungary; 3 Institute of Chemistry,Eötvös Loránd University, Budapest, H-1117, HungaryIntroductionPemphigus vulgaris (PV) is an autoimmune, intraepithelial, blistering disease affecting theskin and mucous membranes and is mediated by circulating and tissue-bound IgG1 andIgG4 autoantibodies directed against keratinocyte cell surfaces. PV induced autoantibodiesbind to the extracellular domains of the desmosomal proteins desmoglein 1 (Dsg1) anddesmoglein 3 (Dsg3). Dsg1 and Dsg3 proteins are transmembranous components ofdesmosomes, that are adhesion units specialized in conferring epidermal keratinocytecohesion and linked to intercellular molecules of the desmosomal plaque. The binding ofantibody to Dsg1 and Dsg3 may have a direct effect on desmosomal adherents or maytrigger a cellular process that results in acantholysis [1].Results and DiscussionAs antibody epitopes are located on the hydrophilic surface of proteins, and many of themat or near -turn structures, we have predicted -turns within the sequences of proteinsDsg1 [2] and Dsg3 [3] using the Chou-Fasman secondary structure prediction method [4]and performed hydrophobicity predictions by Eisenberg et al. [5]. Segments with lowprobability of -turn secondary structure (P -turn0) were dropped. We have reinforced our results using thePredictProtein website [6]. According to these results pentadecapeptides overlapping in fiveamino acid residues were synthesized in duplicates on hydroxypropylmethacrylate pinswith Fmoc/tBu chemistry [7] covering large parts of the extracellular domains of proteinsDsg1 and Dsg3. The side chain protecting groups were removed with trifluoroacetic acid inthe presence of scavengers, but the peptides remained covalently attached to the pins. Todetect the interaction between the autoantibodies and the synthetic peptides ELISAs(Enzyme Linked Immunosorbent Assay) were performed with the pin-attached peptidesusing sera obtained from five PV patients (previously diagnosed as Dsg1 or Dsg3 positive)and a healthy control.Fig. 1. Serum autoantibody binding to the pin-attached peptides within region 76-100 ofprotein Dsg1 (a) and within region 54-78 of protein Dsg3 (b).474