Trypanosoma cruzi: Shedding of surface antigens as membrane vesicles

Detection and partial characterization of Trypanosoma cruzi soluble antigens (SAg) in urine, as well as demonstration of parasite circulating antigens (CAg) in serum from pediatric patients with acute (10 patients) and congenital (10 patients) Chagas' disease, are reported Classical techniques for parasite detection and antibody serology were also conducted in both groups Samples collected before the onset of parasiticidal drug treatment were tested by an enzyme-linked immunosorbent assay for SAg and CAg demonstration The control population consisted of 6 children with acute toxoplasmosis, 6 with cutaneous leishmaniasis, and 20 healthy individuals Patients with acute cases were 100% positive for both SAg and CAg, whereas patients with congenital disease were 80% CAg positive and 100% SAg positive Controls yielded negative results in all cases Partial characterization of SAg from two patients with acute disease was performed by iodination, affinity chromatography, immunoprecipitation, and two-dimensional gel electrophoresis Two different antigenic glycoproteins (80 kilodaltons, pI 6 to 65 and 55 kilodaltons, pI 65 to 7) were identified by these methods Traditional serology and classical parasitologic tests failed, each in a different way, to provide an accurate diagnosis in the total of our patients The enzyme-linked immunosorbent assay for SAg detection proved to be the most effective procedure for achieving early and precise proof of infection in acute and congenital cases of Chagas' disease

Antigenuria in infants with acute and congenital Chagas' disease.

Effect of Trypanosoma cruzi released antigens binding to non-infected cells on anti-parasite antibody recognition and expression of extracellular matrix components

Chagas disease, caused by Trypanosoma cruzi, although endemic in many parts of Central and South America, is emerging as a global health threat through the potential contamination of blood supplies. Consequently, in the absence of a gold standard assay for the diagnosis of Chagas disease, additional antigens or strategies are needed. A proteomic analysis of the trypomastigote excreted-secreted antigens (TESA) associated with exosomal vesicles shed by T. cruzi identified ∼80 parasite proteins, with the majority being trans-sialidases. Mass spectrometry analysis of immunoprecipitation products performed using Chagas immune sera showed a marked enrichment in a subset of TESA proteins. Of particular relevance for diagnostic applications were the retrotransposon hot spot (RHS) proteins, which are absent in Leishmania spp., parasites that often confound diagnosis of Chagas disease. Interestingly, serological screens using recombinant RHS showed a robust immunoreactivity with sera from patients with clinical stages of Chagas ranging from asymptomatic to advance cardiomyopathy and this immunoreactivity was comparable to that of crude TESA. More importantly, no cross-reactivity with RHS was detected with sera from patients with malaria, leishmaniasis, toxoplasmosis, or African sleeping sickness, making this protein an attractive reagent for diagnosis of Chagas disease.

https://jcm.asm.org/content/jcm/55/3/744.full.pdf

Characterization and Diagnostic Application of Trypanosoma cruzi Trypomastigote Excreted-Secreted Antigens Shed in Extracellular Vesicles Released from Infected Mammalian Cells

Comparison of chagasic and non-chagasic myocardiopathies by ELISA and immunoblotting with antigens of Trypanosoma cruzi and Trypanosoma rangeli.

Circulating antigens were detected in sera of mice experimentally infected with a high close of Trypanosoma cruzi by reaction with sera from chronically infected mice. The immunodiffusion reaction between homologous acute and chronic sera produced four precipitation lines. By reaction with chronic mouse serum, circulating antingens were detected in sera from heavily infected hamsters, dogs, rabbits and in sera from chagasic patients. A reaction was also found in urine from acutely infected mice and dogs. Trypanosoma cruzi exoantigen was detected in trypanosome culture medium and in the supernatant of infected cell cultures. Attempts to isolate the antigens are described.

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Klaus-Dieter Hungerer

Papers

Trypanosoma cruzi: circulating antigens