ASP-2/Trans-sialidase chimeric protein induces robust protective immunity in experimental models of Chagas’ disease

Abstract

Immunization with the Amastigote Surface Protein-2 (ASP-2) and Trans-sialidase (TS) antigens either in the form of recombinant protein, encoded in plasmids or human adenovirus 5 (hAd5) confers robust protection against various lineages of Trypanosoma cruzi. Herein we generated a chimeric protein containing the most immunogenic regions for T and B cells from TS and ASP-2 (TRASP) and evaluated its immunogenicity in comparison with our standard protocol of heterologous prime-boost using plasmids and hAd5. Mice immunized with TRASP protein associated to Poly-ICLC (Hiltonol) were highly resistant to challenge with T. cruzi, showing a large decrease in tissue parasitism, parasitemia and no lethality. This protection lasted for at least 3 months after the last boost of immunization, being equivalent to the protection induced by DNA/hAd5 protocol. TRASP induced high levels of T. cruzi-specific antibodies and IFNγ-producing T cells and protection was primarily mediated by CD8+ T cells and IFN-γ. We also evaluated the toxicity, immunogenicity, and efficacy of TRASP and DNA/hAd5 formulations in dogs. Mild collateral effects were detected at the site of vaccine inoculation. While the chimeric protein associated with Poly-ICLC induced high levels of antibodies and CD4+ T cell responses, the DNA/hAd5 induced no antibodies, but a strong CD8+ T cell response. Immunization with either vaccine protected dogs against challenge with T. cruzi. Despite the similar efficacy, we conclude that moving ahead with TRASP together with Hiltonol is advantageous over the DNA/hAd5 vaccine due to pre-existing immunity to the adenovirus vector, as well as the cost-benefit for development and large-scale production.

Vaccination with parasite-specific TcTASV proteins combined with recombinant baculovirus as a delivery platform protects against acute and chronic Trypanosoma cruzi infection

“…Several vaccines against T. cruzi have been pre-clinically tested in animal models, using different antigens and platforms. Most assayed antigens are well-characterized parasite virulence factors belonging to large multigene families, such as trans -sialidase, ASP-2, and cruzipain ( Tzelepis et al., 2008 ; Haolla et al., 2009 ; Bontempi et al., 2015 , 2017 ; Cerny et al., 2020 ; Moraschi et al., 2021 ; Castro et al., 2023 ; Jha et al., 2023 ). However, to date, none antigen-defined vaccines have been able to induce an immune response that avoids an initial infection with the parasite.…”

Protective Efficacy of the Epitope-Conjugated Antigen N-Tc52/TSkb20 in Mitigating Trypanosoma cruzi Infection through CD8+ T-Cells and IFNγ Responses

“…Mice were inoculated with three doses, three weeks apart, via the subcutaneous route, as previously reported [ 30 , 44 , 45 , 46 ], consisting of 50 μL containing 20 μg of chimeric protein and 15 μg of QuilA adjuvant (InvivoGen, Toulouse, France). Additional groups received injections of 20 μg rTc52 + 15 μg QuilA, 20 μg rTS + 15 μg QuilA, or QuilA (non-vaccinated).…”

“…These chimeric protein vaccines have been shown to produce robust immune responses. Reports describe vaccines utilizing chimeric proteins containing multiple epitopes, such as TRASP (ASP-2/Trans-sialidase) and Traspain (N-terminal domain of Cruzipain, an α-helix linker from iTS and the central region of ASP2) against T. cruzi , chimT (a polypeptide based on T-cell epitopes) against Leishmania , or TryPan (a polypeptide based on conserved CD8+ T-cell epitopes) against Leishmania and T. cruzi [ 29 , 30 , 31 , 32 ]. In this study, we generated a chimeric vaccine named N-Tc52/TSkb20, incorporating N-Tc52 and two copies of the TSkb20 epitope.…”