Trypanosoma cruziubiquitin as an antigen in the differential diagnosis of Chagas disease and leishmaniasis

Abstract

In the present report we describe Trypanosoma cruzi ubiquitin as an antigen to be utilized in the differential diagnosis of Chagas disease and leishmaniasis. Initially, recombinant T. cruzi ubiquitin was evaluated against a panel of sera by phage dot immunoassay, showing a good performance against chagasic sera. However, the presence of a carboxy-terminal tail region encoding a ribosomal protein homologous to a related protein present in the genome of Leishmania sp. gave significant cross-reactivity with leishmanial sera. Therefore, ubiquitin was purified by a simple biochemical protocol and its immunoreactivity was studied by enzyme-linked immunosorbent assay. Analysis of 104 sera indicates that the response to ubiquitin is very sensitive towards chronic chagasic sera (98%) and, more important, highly species-specific, presenting better performance compared to the use of the recombinant protein or the total epimastigote extracts when tested against a panel of leishmanial sera, where out of a total of 70 sera tested, only five sera from the mucocutaneous form of the disease reacted with T. cruzi ubiquitin. On the other hand, Leishmania ubiquitin was not recognized by chagasic sera, but was recognized by sera from different forms of leishmaniasis. These results make ubiquitin an excellent candidate to be used in the differential diagnosis of these two parasitic diseases. The molecular basis for this highly species-specific response is discussed.

Pentamidine Is an Antiparasitic and Apoptotic Drug That Selectively Modifies Ubiquitin

“…3) in the presence of pentamidine. We choose Ub for our structural studies because it is the most highly conserved protein known, and because it is present in kinetoplastid parasites, including all Leishmania species [19]. Moreover, Ub is a crucial protein for cell functioning through the Ub-proteasome pathway in the degradation of proteins involved in i) cell-cycle regulation, ii) modulation of cell-surface receptors and ion channels, and iii) antigen processing and presentation [20].…”

Cross-Reactivity Using Chimeric Trypanosoma cruzi Antigens: Diagnostic Performance in Settings Where Chagas Disease and American Cutaneous or Visceral Leishmaniasis Are Coendemic

“…Despite the increased specificity offered by recombinant antigens, reports of cross-reactivity with Leishmania spp. have persisted (13, 16–19). As a result, commercial tests employing recombinant antigenic matrices have been known to lead to false-positive results in Leishmania -exposed individuals, primarily in settings in which these infections occur concomitantly—a growing problem since areas where each pathogen is endemic have overlapped in Brazil and elsewhere (16, 17, 20).…”

Development and Application of an ELISA Assay Using Excretion/Secretion Proteins from Epimastigote Forms ofT. cruzi(ESEA Antigens) for the Diagnosis of Chagas Disease

“…Cannnova et al [32] standardized an ELISA assay using a crude epimastigote antigen; the sensitivity and specificity of the test was 96% and 97%, respectively. Moreover, Telles et al [33] used T. cruzi ubiquitin as a differential diagnostic antigen to distinguish tripanosomiasis and leshmaniosis with an ELISA test at a sensitivity and specificity of 98% and 93.8%, respectively, Additionally, Schechter et al [34] developed an ELISA assay using a 90 kDa purified protein, the sensibility and specificity of this assay are 96.6% and 91.9%, respectively.…”