Immunization of Mice with a TolA-Like Surface Protein ofTrypanosoma cruziGenerates CD4⁺T-Cell-Dependent Parasiticidal Activity

Abstract

The gene family encoding a trypomastigote-specific protein restricted to the part of the flagellum in contact with the cell body of the trypomastigote form of Trypanosoma cruzi has been isolated, characterized, and expressed in a baculovirus expression system. The gene family contains three tandemly repeated members that have 97 to 100% sequence identity. The predicted protein encoded by the gene family has both significant amino acid sequence identity and other physical and biological features in common with the TolA proteins of Escherichia coli and Pseudomonas aeruginosa. Based on these similarities, we have designated this gene family tolT. Immunization of mice with recombinant TolT generates a population of CD4+ T lymphocytes that recognize T. cruzi-infected macrophages, resulting in the production of gamma interferon (IFN-γ), which leads to NO production and a 50 to 60% reduction in parasite numbers compared to that seen with infected macrophages incubated with naive T cells. This population of T cells also produces both IFN-γ and interleukin 2 (IL-2) but not IL-4 or IL-5 when incubated with spleen cells stimulated with TolT antigen, indicating that they are of the T-helper 1 type. T cells from mice chronically infected with T. cruzi also produce significant levels of IFN-γ when cocultured with macrophages and either TolT protein or paraflagellar rod protein, indicating that both of these flagellar proteins produce positive T-cell responses in mice chronically infected with T. cruzi.

Trypanosoma cruzi-Infected Human Macrophages Shed Proinflammatory Extracellular Vesicles That Enhance Host-Cell Invasion via Toll-Like Receptor 2

“…In this analysis only six parasite proteins were found in EVs from macrophages infected with T. cruzi i.e., HSP60, tryparedoxin peroxidase, trans-sialidase Group II, flagellar calcium-binding protein, surface protein TolT and paraflagellar rod protein 2 (Lobo et al, 2019). These parasite proteins are involved in the recognition of the parasite by host cells, invasion, the adhesion of host cells, metabolism and the induction of the host immune response (Godsel et al, 1995;Quanquin et al, 1999;Mattos et al, 2014;Urményi et al, 2014;Girard et al, 2018).…”

Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology

“…To validate the results obtained, we selected several of these identified proteins and analyzed their surface distribution by fluorescence microscopy. Recombinant Calpain-like cysteine peptidase (CLCP) [ 47 ], Kinetoplastid membrane protein-11 (KMP-11) [ 41 , 42 ] and Tol-T [ 40 ] were expressed in bacteria to elicit antibodies in mice. Immunofluorescence assays ( Fig 5 ) determined that these proteins were also distributed in discrete membrane domains, indicating a correlation with lipid rafts purification.…”

GPIomics: global analysis of glycosylphosphatidylinositol‐anchored molecules ofTrypanosoma cruzi

“…Amastin, gp63, mucin-like, and TolT were also represented by multiple sequences ( Table I ). TolT is an immunogenic surface protein found on T. cruzi trypomastigotes ( Quanquin et al , 1999 ) with protein sequence identity and biochemical and biological traits in common with the bacterial TolA proteins, which are part of the Tol system of most gram-negative bacteria and are involved in the outer membrane stability ( Lazzaroni et al , 2002 ). Taken together, our GPI-anchoring prediction data indicates that a high proportion of the T. cruzi genes possibly encode GPI-anchored proteins.…”