Design of multi-epitope peptides containing HLA class-I and class-II-restricted epitopes derived from immunogenic Leishmania proteins, and evaluation of CD4+ and CD8+ T cell responses induced in cured cutaneous leishmaniasis subjects

• Published in: PLoS neglected tropical diseases Vol. 14; no. 3; p. e0008093
• Main Authors: Hamrouni, Sarra, Bras-Gonçalves, Rachel, Kidar, Abdelhamid, Aoun, Karim, Chamakh-Ayari, Rym, Petitdidier, Elodie, Messaoudi, Yasmine, Pagniez, Julie, Lemesre, Jean-Loup, Meddeb-Garnaoui, Amel
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.03.2020; Public Library of Science (PLoS)
• Subjects: Adult; Antigenic determinants; Antigens; Antigens, Protozoan; Antigens, Protozoan - genetics; Antigens, Protozoan - immunology; Biology and Life Sciences; CD4 antigen; CD4-Positive T-Lymphocytes; CD4-Positive T-Lymphocytes - immunology; CD8 antigen; CD8-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes - immunology; Cells; Cutaneous leishmaniasis; Cytokines; Deoxyribonucleic acid; Disease control; DNA; ELISA; Enzyme-Linked Immunosorbent Assay; Epitopes; Epitopes, T-Lymphocyte; Epitopes, T-Lymphocyte - genetics; Epitopes, T-Lymphocyte - immunology; Female; Flow Cytometry; Genetic testing; Granzyme B; Granzymes; Granzymes - analysis; Guanosine triphosphatases; Health aspects; Histocompatibility antigen HLA; Histocompatibility Antigens Class I; Histocompatibility Antigens Class I - metabolism; Histocompatibility Antigens Class II; Histocompatibility Antigens Class II - metabolism; Histones; HLA antigens; Humans; Identification; Immune response (cell-mediated); Immune system; Immunodominance; Immunogenicity; Immunological memory; Infections; Interferon-gamma; Interferon-gamma - analysis; Interleukin 10; Interleukin-10 - analysis; Leishmania; Leishmania - immunology; Leishmaniasis, Cutaneous; Leishmaniasis, Cutaneous - immunology; Leukocytes; Life Sciences; Lymphocytes; Lymphocytes T; Male; Medicine and Health Sciences; Memory cells; Middle Aged; Molecules; Parasites; Parasitic diseases; Peptides; Pharmacological research; Physiological aspects; Pools; Prevention; Protein Binding; Proteins; Public health; Recombinant Fusion Proteins; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - immunology; Recombinant Fusion Proteins - metabolism; Research and Analysis Methods; Servers; T cells; Tropical diseases; Tumor Necrosis Factor-alpha; Tumor Necrosis Factor-alpha - analysis; Tumor necrosis factor-α; Vaccines; Vector-borne diseases; Volunteers; Young Adult; γ-Interferon; Tunisia; France; Germany
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0008093

Human leishmaniasis is a public health problem worldwide for which the development of a vaccine remains a challenge. T cell-mediated immune responses are crucial for protection. Peptide vaccines based on the identification of immunodominant T cell epitopes able to induce T cell specific immune responses constitute a promising strategy. Here, we report the identification of human leukocyte antigen class-I (HLA-I) and -II (HLA-II)-restricted multi-epitope peptides from Leishmania proteins that we have previously described as vaccine candidates. Promastigote Surface Antigen (PSA), LmlRAB (L. major large RAB GTPase) and Histone (H2B) were screened, in silico, for T cell epitopes. 6 HLA-I and 5 HLA-II-restricted multi-epitope peptides, able to bind to the most frequent HLA molecules, were designed and used as pools to stimulate PBMCs from individuals with healed cutaneous leishmaniasis. IFN-γ, IL-10, TNF-α and granzyme B (GrB) production was evaluated by ELISA/CBA. The frequency of IFN-γ-producing T cells was quantified by ELISpot. T cells secreting cytokines and memory T cells were analyzed by flow cytometry. 16 of 25 peptide pools containing HLA-I, HLA-II or HLA-I and -II peptides were able to induce specific and significant IFN-γ levels. No IL-10 was detected. 6 peptide pools were selected among those inducing the highest IFN-γ levels for further characterization. 3/6 pools were able to induce a significant increase of the percentages of CD4+IFN-γ+, CD8+IFN-γ+ and CD4+GrB+ T cells. The same pools also induced a significant increase of the percentages of bifunctional IFN-γ+/TNF-α+CD4+ and/or central memory T cells. We identified highly promiscuous HLA-I and -II restricted epitope combinations from H2B, PSA and LmlRAB proteins that stimulate both CD4+ and CD8+ T cell responses in recovered individuals. These multi-epitope peptides could be used as potential components of a polytope vaccine for human leishmaniasis.