Correlation between the virulence of T. cruzi strains, complement regulatory protein expression levels, and the ability to elicit lytic antibody production

Abstract

Trypanosoma cruzi trypomastigotes are able to resist lysis via the complement system, which involves many surface proteins including the complement regulatory protein (CRP). To examine the diversity in CRP recognition among strains of T. cruzi, the expression levels of the translated protein on trypomastigote surfaces were analyzed by flow cytometry, and associations between protein expression and the biological behavior of these strains, especially the ability to induce lytic antibodies in animal models, were assessed. The highly virulent T. cruzi strains Ninoa, INC-5, and Colombiana and the less virulent strains CL-Brener, LGB-231, and JG were used in the experiments. An expression profile analysis showed that the Colombiana and INC-5 strains have higher translated protein levels and induced higher production of antibodies in mice than the other strains. Our results indicated that there are differences in the surface expression of CRP between parasite strains, with a tendency for the most virulent strains to have higher expression levels. Combined, these results contribute to a better understanding of CRP functions and the complexity of host-parasite interactions, considering the large number of virulence factors involved in the process.

Complement system contributes to modulate the infectivity of susceptible TcI strains of Trypanosoma cruzi

“…Both are able to inhibit the assembly of C3 convertases in all three pathways by binding to C4b and C3b ( Tambourgi et al 1993 , , Norris 1998 ). A recent study has also demonstrated a correlation between CRP protein level and strain virulence in vivo ( Henrique et al 2016 ). Our qRT-PCR assay showed a three-fold lower mRNA expression for T-DAF, CRP, as well as for CRIT, a C2-binding protein and hence an inhibitor of classical and lectin pathways ( Cestari et al 2008 ), in the Ninoa strain.…”

The Unsolved Jigsaw Puzzle of the Immune Response in Chagas Disease

“…Normally, it is not expressed on the epimastigote and amastigote forms surface, but their exogenous expression on epimastigotes renders them less susceptible to complement-mediated lysis (20, 21). Some authors have proposed a positive correlation between the TcCRP expression level and the virulence in different T. cruzi strains (22). However, evidence on that regards is scarce and inconclusive.…”

Trypanosoma vivax infection in sheep: Different patterns of virulence and pathogenicity associated with differentially expressed proteomes

“…Differences in the severity and progression of trypanosome-caused diseases (virulence and pathogenicity, as defined in this study) have been described for infections of T. bruceigambiense ( Holzmuller et al, 2008 , Kaboré et al, 2018 ), T. bruceirhodesiense ( Maclean et al, 2007 , Muchiri et al, 2015 ), T. congolense ( Bengaly et al, 2002a , Bengaly et al, 2002b , Grébaut et al, 2009 , Masumu et al, 2006 ), T. evansi ( Perrone et al, 2018 , Verdillo et al, 2012 ) and T. cruzi ( Andrade et al, 1985 , Belew et al, 2017 , Henrique et al, 2016 , Lauria-Pires and Teixeira, 1996 ). Similarly, differences in virulence and pathogenicity have been recognized between East and West African strains of T. vivax , the West African strains being generally more pathogenic to cattle ( Gardiner, 1989 ).…”