A novel Trypanosoma cruzi secreted antigen as a potential biomarker of Chagas disease

Abstract

Chagas drug discovery has been hampered by a lack of validated assays to establish treatment efficacy in pre-clinical animal models and in patients infected with T. cruzi. Reduced levels of parasite secreted antigens in the blood of infected hosts could be used to demonstrate treatment efficacy. A published proteomic study of parasite secreted antigens identified the hypothetical protein Tc_5171 as a secreted antigen. In this report, we developed Tc_5171 specific antibodies and showed that the native protein was expressed by the three life cycle stages of the parasite. Anti-peptide antibodies were able to detect the parasite antigen in blood of infected mice during the acute and the chronic phase of infection. Benznidazole treatment of infected mice significantly reduced their blood antigen levels. Of clinical significance, patients diagnosed with Chagas disease, either asymptomatic or with cardiac clinical symptoms had significantly higher Tc_5171 antigen levels compared to endemic controls. Pair-wise analysis, before and after Benznidazole treatment, of patients with asymptomatic Chagas disease showed a significant reduction in antigen levels post treatment. Taken together, our results indicate that Tc_5171 could be used as a novel biomarker of Chagas disease for diagnosis and to assess treatment efficacy.

Isolation and molecular characterization of circulating extracellular vesicles from blood of chronic Chagas disease patients

“…The use of EVs as biomarker has already been proposed (Borges et al, 2016; Cestari et al, 2012; Diaz Lozano et al, 2017; de Pablos Torro et al, 2018; van der Pol et al, 2014; Soekmadji et al, 2020) including detection of specific noncoding RNAs (Ballinas‐Verdugo et al, 2021; Ferreira et al, 2017, 2014; Linhares‐Lacerda et al, 2018, 2015; Navarro et al, 2015; Nonaka et al, 2021). In addition, the presence of circulating antigens (Ashmus et al, 2013; Daltro et al, 2019; Lorca et al, 1995; Nagarkatti et al, 2020; Santos et al, 2021; Thomas et al, 2012; Zarate‐Blades et al, 2007) or altered expression of host proteins (Bravo‐Tobar et al, 2015; Pedrosa, 2021; Saraiva et al, 2013; Wang et al, 2013, 2010, 2012) are all proposed to follow the disease evolution, but is still necessary a more robust set of tests for the follow up of CCD patients, mainly regarding the therapeutic effectivity.…”

Trypanosoma cruzi Secreted Cyclophilin TcCyP19 as an Early Marker for Trypanocidal Treatment Efficiency

“…In this work, we analyzed a secreted T. cruzi protein to assess the efficiency of parasiticidal treatments in T. cruziinfected hosts. When trypanocidal drugs reduce parasite loads in treated hosts, a logical consequence is the lower amount of parasite-secreted proteins [34].…”

New chemotherapy regimens and biomarkers for Chagas disease: the rationale and design of the TESEO study, an open-label, randomised, prospective, phase-2 clinical trial in the Plurinational State of Bolivia

“…113 The new data will provide useful information on the requirements of follow-up duration to assess the true efficacy of chemotherapy in CCD patients. Such efficacy will be evaluated using standard methodologies for CS and qPCR, as well as NCS, such as lytic anti-α-Gal antibodies, 43-48 60 76 antibodies against KMP11, HSP70, PFR2 and peptide 3973, [51][52][53][54][55] and parasite-derived BMK TESA, using an aptamer-based assay, [56][57][58] as described above. It is known that the efficacy of CCD treatment depends, among other factors, on the infecting T. cruzi strain or genotype.…”

“…[51][52][53][54][55] The parasite-derived BMK involves the detection of trypomastigote excreted/secreted antigens (TESA) by an aptamer-based assay. [56][57][58] BMKs will be evaluated at baseline, during treatment, at EOT, and through a 3-year follow-up interval at the times indicated above in Primary Objectives and figure 1. Changes in BMKs' levels will be correlated with parasitic load clearance, as measured by qPCR.…”

“…90 TESA BMK levels were also shown to significantly decrease in CCD patients following BZN SoC treatment. 58 It was recently reported that an aptamer-based, non-serological, non-PCR assay could detect TESA BMKs circulating in the blood of infected mice. 56 57 RNA aptamers selected to bind with high specificity and affinity to TESA were used in enzyme-linked aptamer assays to detect TESA BMKs in plasma from infected mice, including chronically infected mice that failed BZN treatment.…”