SEARCHING FOR SHORT EPITOPIC SEQUENCES IN CANINE PEMPHIGUS FOLIACEUS: PRELIMINARY RESULTS

The present study aims to identify short peptide sequences characterized by a low level of similarity to the canine proteome, and responsible for autoimmune response that characterizes canine pemphigus foliaceous (cPF). As already demonstrated by several authors, in the human model of pemphigus foliaceous and pemphigus vulgaris short peptide sequences from the two antigens of PF and PV (Dsg1 and Dsg3 respectively) with low similarity to the host proteome (mouse and human), are endowed with a high epitopic power (Kanduc, 2009; Kanduc, 2008; Lucchese et al., 2006; Angelini et al.,2006). Five sera from dogs affected by PF were tested with Dot‐blot Immunoassay to evaluate the presence of autoantibodies against two peptides with low similarity to the dog proteome (Canfa, Canis Familiaris): Dsg1_CANFA49‐60 and Dsg3_CANFA48‐59. Two peptides with high similarity to the dog proteome were employed as negative controls : Dsg3_CANFA189‐203 and Dsg3_CANFA372‐379. The same peptide platform was used to test sera from healthy dogs. All the dogs with PF showed antibody reactivity to the low similarity peptide Dsg3_CANFA48‐59. No positivity was detected against the low similarity peptide Dsg1_CANFA49‐60 and the two high‐similarity peptides Dsg3_CANFA189‐203 and Dsg3_CANFA372‐379. No sera belonging to healthy dogs has recognized the two peptide sequences with low similarity neither the two high‐similarity peptides. The data presented in this study should be interpreted as preliminary results of a larger research project which is still in progress. In fact, thanks to the collaboration of many dermatologists throughout the country we are expanding our study to obtain a statistically significant number of samples. However, to date, we report the evidence that circulating antibodies present in the sera of dogs with PF recognize the Dsg3_CANFA48‐59 low similarity peptide sequence. Further studies need to confirm our data and give us a better understanding of the molecular mechanisms at the basis of the PF.