The F1F3 Recombinant Chimera of Leishmania donovani-Nucleoside Hydrolase (NH36) and Its Epitopes Induce Cross-Protection Against Leishmania (V.) braziliensis Infection in Mice

Abstract

Leishmania ( V .) braziliensis is the etiological agent of Cutaneous (CL) and Mucocutaneous leishmaniasis (ML) in the New World. CL can be more benign but ML can be severe and disfiguring. Immunity to these diseases include hypersensitivity, an enhanced inflammatory response with strong IFN-γ and TNF-α secretion. Additionally, the production of IL-10 which down modulates the immune response is reduced. The Nucleoside hydrolase (NH36) of Leishmania ( L .) donovani is the main antigen of the Leishmune veterinary vaccine and its F3 domain induces a CD4 + T cell-mediated protection against L . ( L .) infantum chagasi infection. Prevention of L . ( L .) amazonensis infection requires in contrast an additional CD8 + T cell mediated response induced by the F1 domain. Consequently, the F1F3 recombinant chimera, which contains both domains cloned in tandem, optimized the vaccine efficacy against L . ( L .) amazonensis mouse infection. We compared the efficacies of NH36, F1, F3, and the FIF3 chimera against L . ( V .) braziliensis mouse infection. The F1F3 chimera increased the NH36 specific IgA and response before and after infection and the IgG and IgG3 levels after challenge. It also induced a 49% stronger intradermal response to leishmanial antigen (IDR) than NH36 that was positively correlated to the levels of IFN-γ and TNF-α, IgG, IgG2a, IgG2b, and IgG3 anti-NH36 antibodies. However, stronger Th1 responses with elevated IFN-γ / IL-10 and TNF-α / IL-10 ratios were promoted by the F3 and F1 vaccines and detected in infected controls while the F1F3 chimera promoted the highest IL-10 secretion, which reduced the pathological Th1 response, and characterized the induction of a mixed and/or T-cell regulatory response. We identified the epitopes responsible for these immune responses. The F3 vaccine induced the earliest immunity and after challenge, the F1F3 chimera promoted the highest CD4 + and CD8 + cytokine-secreting T cell responses, and the predominant frequencies of multifunctional CD4 + and CD8 + IL-2 + TNF-α + IFN-γ + T cells. Also as observed against L . ( L .) amazonensis infection, the F1F3 chimera showed the strongest reduction of the ear lesions sizes induced by L . ( V .) braziliensis . Our results confirm the potential use ...

Evaluation of different total Leishmania amazonensis antigens for the development of a first-generation vaccine formulated with a Toll-like receptor-3 agonist to prevent cutaneous leishmaniasis

“…Currently, there is not any approved vaccine against human leishmaniasis. 5 Nevertheless, several vaccine formulations are under evaluation in preclinical 6 , 7 , 8 and clinical trials (ClinicalTrials.gov Identifier: NCT02894008 and NCT03969134). The need to induce a Th1-type immune response in order to obtain protection was shown in Leishmania -murine models protection studies and in the immune profiles of self-healed individuals.…”

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

“…Furthermore, we noticed that most of the peptide pools containing both HLA-I and -II epitopes induced higher amounts of IFN-γ than those containing only HLA-I or -II epitopes. These results emphasize the importance to include both CD4 + and CD8+ specific T cell epitopes in peptide based vaccines [67,88,89].…”

“…However, as we have described here, Agallou and colleagues designed multi-epitope peptides containing both MHC-I and -II restricted epitopes that were able to induce both IFN-γ-producing CD4+ and CD8+ T cells in immunized mice [40]. More interestingly, it was recently reported that mice vaccination with a chimera vaccine composed of F1 and F3 NH36 domains, holding respectively, epitopes involved in both CD8+ and CD4+ T cell mediated protective responses, was more efficient than vaccination with either of the domains injected separately [67,89].…”

“…However, no increases were observed in the frequencies of multifunctional CD4+ T cells producing simultaneously IFN-γ, TNF-α and IL-2. The induction of high proportions of both CD4+ and CD8+ IFN-γ+TNF-α+ by predicted T cell epitopes from NH36 or phosphoenolpyruvate carboxykinase (PEPCK) Leishmania proteins was described, respectively, in infected and vaccinated mice [67,89,99]. However, as far as we know, no study has described the detection of multifunctional T cells in response to stimulation by HLA restricted peptides in humans.…”

Protective or Detrimental? Understanding the Role of Host Immunity in Leishmaniasis

“…Highly conserved immunogenic proteins or epitopes between Leishmania spp. have the potential to confer cross-protection as demonstrated for L. donovani nucleoside hydrolase (NH36) and/or its recombinant fragments F1 (N-terminal domain) and F3 (C-terminal domain) formulated with saponin, which induced antigen-specific protection in BALB/c mice against L. amazonensis and L. braziliensis [157][158][159]. Other Leishmania proteins evaluated as vaccine candidates are reviewed in [160].…”