Identification of Proteins in Promastigote and Amastigote-like Leishmania Using an Immunoproteomic Approach

Vinicio T S Coelho,Jamil S Oliveira,Mariana C Duarte,Paula S Lage,Eduardo A F Coelho,Marcelo M Santoro,Diogo G Valadares,Miguel A Chávez-Fumagalli,Ana Paula Fernandes,Carlos A P Tavares,Manuel Soto,Rodrigo Correa-Oliveira

doi:10.1371/journal.pntd.0001430

Abstract

BackgroundThe present study aims to identify antigens in protein extracts of promastigote and amastigote-like Leishmania (Leishmania) chagasi syn. L. (L.) infantum recognized by antibodies present in the sera of dogs with asymptomatic and symptomatic visceral leishmaniasis (VL).Methodology/Principal FindingsProteins recognized by sera samples were separated by two-dimensional electrophoresis (2DE) and identified by mass spectrometry. A total of 550 spots were observed in the 2DE gels, and approximately 104 proteins were identified. Several stage-specific proteins could be identified by either or both classes of sera, including, as expected, previously known proteins identified as diagnosis, virulence factors, drug targets, or vaccine candidates. Three, seven, and five hypothetical proteins could be identified in promastigote antigenic extracts; while two, eleven, and three hypothetical proteins could be identified in amastigote-like antigenic extracts by asymptomatic and symptomatic sera, as well as a combination of both, respectively.Conclusions/SignificanceThe present study represents a significant contribution not only in identifying stage-specific L. infantum molecules, but also in revealing the expression of a large number of hypothetical proteins. Moreover, when combined, the identified proteins constitute a significant source of information for the improvement of diagnostic tools and/or vaccine development to VL.

Highlights

Visceral leishmaniasis (VL) is an important parasitic disease, with a worldwide distribution in 88 countries, where a total of 350 million people may be at risk
Canine visceral leishmaniasis (CVL) is an important emerging zoonosis caused by Leishmania (Leishmania) infantum in the Mediterranean and Middle East and L. (L.) chagasi
The present study focused on comparing the protein expression profiles of the promastigote and amastigote-like stages of L. infantum, by means of a protein separation by two-dimensional electrophoresis and identification by mass spectrometry

Summary

Introduction

Visceral leishmaniasis (VL) is an important parasitic disease, with a worldwide distribution in 88 countries, where a total of 350 million people may be at risk. In Brazil, the disease is an endemic zoonosis caused by the parasitic protozoa Leishmania (Leishmania) chagasi syn. To reduce the transmission of parasites between dogs and humans, it is necessary, among other aspects, to diagnose canine visceral leishmaniasis (CVL) as early as possible, by means of sensitive and specific diagnostic tools [2,3]. Dogs develop three different stages of the disease: symptomatic, oligosymptomatic, and asymptomatic [4]. A high number of infected dogs remain asymptomatic and present low levels of specific antibodies; some dogs do develop a few mild symptoms, which are classified as oligosymptomatic [4]. The present study aims to identify antigens in protein extracts of promastigote and amastigote-like Leishmania (Leishmania) chagasi syn. L. (L.) infantum recognized by antibodies present in the sera of dogs with asymptomatic and symptomatic visceral leishmaniasis (VL)

Methods

Results

Discussion

Conclusion