e Davarpanah - Department of Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran. Department of Immunotherapy and Leishmania Vaccine Research, Pasteur Institute of Iran, Tehran, Iran
n Seyed - Department of Immunotherapy and Leishmania Vaccine Research, Pasteur Institute of Iran, Tehran, Iran.
s Rafati - Department of Immunotherapy and Leishmania Vaccine Research, Pasteur Institute of Iran, Tehran, Iran.
r Safaralizadeh - Department of Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
t Taheri - Department of Immunotherapy and Leishmania Vaccine Research, Pasteur Institute of Iran, Tehran, Iran.

Leishmaniasis is one of the neglected diseases in the world that is transmitted through the bite of female sand fly of Phlebotomus genus. No treatment or vaccine has been introduced until now. Here, we used Lactococcus lactis as a nonpathogenic expression system to present one of the most important Phlebotomus papatasi salivary proteins, SP15 protein, to BALB/c immune system.Methods: SP15 epitope prediction was accomplished with different online software (SYFPEITHI, RANKPEP, NetMHC, IEDB, EpiJen and NetCTL) to clarify existing immunogenic T-cell epitopes. For prediction of any exposed domain of SP15 to immune system, second and third structures predicted with RaptorX property and Swiss-model, respectively. Whole SP15-EGFP and EGFP genes were codon optimized, synthesized to express in L. lactis. Both genes were cloned at downstream of PrtP signal peptide sequence in pNZ8121 vector to be presented on bacterial cell-wall. The expressed protein was confirmed by western blotting using anti-GFP antibody, fluorescence microscopy and flow- cytometry.Results: Some of online software with different algorithms confirmed the presence of immunogenic epitopes that are able to trigger the immune responses through HLA-I (IMHECAKKV, AIQEYDKTI, YQYYGFAM, SLKADIRKI) and HLA-II (IMHECAKKV, FVAMDNNIA, YYGFVAMDN, IRTFSNVLI). Secondary and tertiary structure of SP15 has shown that none of the epitopes are criptic in SP15 protein. SP15 expression in L. lactis was monitored and confirmed through different tools. Discussion: SP15 has a high score immunogenic epitope and can consider as an epitope base-or whole antigen vaccines candidate. In addition, SP15 expressing L. lactis is developed to be used in vaccination experiments.

Leishmaniasis, SP15, Phlebotomus papatasi, Lactococcus lactis, pNZ8121, HLA I/II