Screening diagnostic candidates fromLeishmania infantumproteins for human visceral leishmaniasis using an immunoproteomics approach

Abstract

There is no suitable vaccine against human visceral leishmaniasis (VL) and available drugs are toxic and/or present high cost. In this context, diagnostic tools should be improved for clinical management and epidemiological evaluation of disease. However, the variable sensitivity and/or specificity of the used antigens are limitations, showing the necessity to identify new molecules to be tested in a more sensitive and specific serology. In the present study, an immunoproteomics approach was performed in Leishmania infantum promastigotes and amastigotes employing sera samples from VL patients. Aiming to avoid undesired cross-reactivity in the serological assays, sera from Chagas disease patients and healthy subjects living in the endemic region of disease were also used in immunoblottings. The most reactive spots for VL samples were selected, and 29 and 21 proteins were identified in the promastigote and amastigote extracts, respectively. Two of them, endonuclease III and GTP-binding protein, were cloned, expressed, purified and tested in ELISA experiments against a large serological panel, and results showed high sensitivity and specificity values for the diagnosis of disease. In conclusion, the identified proteins could be considered in future studies as candidate antigens for the serodiagnosis of human VL.

A candidate vaccine for human visceral leishmaniasis based on a specific T cell epitope-containing chimeric protein protects mice against Leishmania infantum infection

“…In our current study, the rationale for selecting T-cell epitopes from Leishmania PHB, EIF5a, LiHyp1, and LiHyp2 proteins is based on our previous studies that demonstrated their vaccine and/or diagnostic potential 27,34,38 . We confirmed the protective activities of the individual recombinant proteins, but demonstrated clearly that ChimeraT was superior.…”

“…In the present study, we designed in silico a recombinant multi-epitope vaccine for VL named ChimeraT. The vaccine contains amino acid sequences corresponding to specific T-cell epitopes from four L. infantum proteins, which we previously showed to be antigenic in canine and/or human disease 27 , 34 , 38 . The most significant findings were that ChimeraT (i) protected mice against L. infantum infection and (ii) induced a Th1-type immune response in PBMC from VL patients after treatment and healthy subjects, which was characterized by high IFN-γ and low IL-10 levels and positive lymphoproliferative responses.…”

“…We have shown that rEIF5a induced partial protection in immunized mice against L. infantum infection, which was related to IFN-γ production mediated by CD4 + and CD8 + T cells. Similarly, an immunoproteomic study suggested that two other Leishmania hypothetical proteins, LiHyp1 and LiHyp2, were also antigenic, since they were recognized by antibodies in VL patients sera, but not by sera from healthy subjects 38 .…”

Liposomal Formulation of ChimeraT, a Multiple T-Cell Epitope-Containing Recombinant Protein, Is a Candidate Vaccine for Human Visceral Leishmaniasis

“…Recently, we designed and developed a synthetic recombinant vaccine called ChimeraT, which contains specific T-cell epitopes from the Leishmania prohibitin, eukaryotic initiation factor 5a, and hypothetical LiHyp1 and LiHyp2 proteins (Lage et al, manuscript submitted). The rationale for choosing these four proteins to develop ChimeraT is based on previous studies that have shown them to be antigenic and immunogenic, and by the fact that they were recognized by antibodies from humans developing VL [ 48 , 49 , 50 , 51 , 52 ]. This recognition by the immune system of infected hosts during active disease suggests that these proteins could have vaccine potential.…”

An immunoproteomics approach to identifyLeishmania infantumproteins to be applied for the diagnosis of visceral leishmaniasis and human immunodeficiency virus co-infection

“…Immunoproteomics is a biotechnological tool also used to identify antigens with a diagnostic application for canine and human VL (Lage et al ., 2019; Santos et al ., 2019; Vale et al ., 2019). In the present work, an immunoproteomics approach was performed in Leishmania infantum antigenic extracts using VL and VL/HIV co-infected patients sera; aiming to identify new candidates to serologically diagnose both patients classes.…”