In silico prediction of promiscuous Leishmania infantum KMP-11, H1, LeIF, CPA, CPB peptides and experimental validation of eliciting CD4+ and CD8+ T-cell specific responses
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Hellenic Pasteur Institute, Greece
Previous studies on leishmaniasis have demonstrated that both IFNγ-producing CD4+ and CD8+ T lymphocytes are significant players in protection mechanisms against visceral disease (Alexander and Brombacher, 2012; Stager and Rafati, 2012). Recent trend on vaccine designing has been shifted to peptide vaccines based on computational prediction of immunodominant T-cell epitopes that are more specific, safe, and easy to produce (Li Pira et al., 2010). Leishmania infantum KMP-11, H1, LeIF, CPA and CPB were screened for antigenic epitopes by using online bioinformatics tools (BIMAS, NetCTL, NetMHCII, SYFPEITHI, EpiJen) on their ability to bind promiscuously to mice and human MHC class I and II molecules. Peptides were selected only if they were characterized as possible epitopes according to their predictive scores obtained by more than two programs used. In that context, 10 “polyepitope” peptides were synthesized containing both MHC class I and II specific epitopes for each protein. To validate the immunogenicity of polyepitope peptides experimentally, BALB/c mice were immunized subcutaneously 3 times with two randomly selected peptide pools. Cellular responses were detected by proliferation assays, flow cytometry and ELISA. Six out of ten (60%) induced proliferative responses in lymph nodes, whereas only three peptides (30%) induced spleen cells proliferation. These peptides were also potent inducers of CD4+IFNγ+ and/or CD8+IFNγ+ T cells as confirmed by flow cytometry. Finally, four peptides were selected for further vaccination experiments against visceral leishmaniasis, CPA_2 (aa 160-189), H1_1 (aa 1-20), LeIF_6 (aa 371-400) and CPB_1 (aa 160-189), based on their ability to induce strong T cell responses, suggesting that promiscuous T-cell epitopes can be identified using reverse vaccinology.
Acknowledgements
This research has been co-financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program "Competitiveness and Entrepreneurship" (OPCE II) of the National Strategic Reference Framework (NSRF).
References
Alexander, J., and Brombacher, F. (2012). T helper1/T helper2 cells and resistance/susceptibility to Leishmania infection: is this paradigm still relevant? Front. Immunol. 2012; 3: 80. doi: 10.3389/fimmu.2012.00080.
Li Pira, G., Ivaldi, F., Moretti, P., and Manca, F. (2010). High throughput T epitope mapping and vaccine development. J. Biomed. Biotechnol. 2010; 2010: 325720. doi: 10.1155/2010/325720.
Stager, S., and Rafati, S. (2012). CD8+T cells in Leishmania infections: frineds or foes? Front. Immunol. 2012; 3: 5. doi: 10.3389/fimmu.2012.00005.
Keywords:
Leishmania,
reverse vaccinology,
T cell epitopes,
KMP-11,
LeIF,
CPA,
CPB,
Histone H1
Conference:
15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013.
Presentation Type:
Abstract
Topic:
Translational immunology and immune intervention
Citation:
Agallou
M,
Koutsoni
O,
Dotsika
E and
Karagouni
E
(2013). In silico prediction of promiscuous Leishmania infantum KMP-11, H1, LeIF, CPA, CPB peptides and experimental validation of eliciting CD4+ and CD8+ T-cell specific responses.
Front. Immunol.
Conference Abstract:
15th International Congress of Immunology (ICI).
doi: 10.3389/conf.fimmu.2013.02.00435
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Received:
01 Apr 2013;
Published Online:
22 Aug 2013.
*
Correspondence:
Dr. Evdokia Karagouni, Hellenic Pasteur Institute, Athens, Greece, ekaragouni@pasteur.gr