Methodological approach to the ex vivo expansion and detection of T. cruzi-specific T cells from chronic Chagas disease patients

PLoS One. 2017 May 26;12(5):e0178380. doi: 10.1371/journal.pone.0178380. eCollection 2017.

Abstract

The discovery of T cell epitopes is essential not only for gaining knowledge about host response to infectious disease but also for the development of immune-intervention strategies. In Chagas disease, given the size and complexity of the Trypanosoma cruzi proteome and its interaction with the host's immune system, the fine specificity of T cells has not been extensively studied yet, and this is particularly true for the CD4+ T cell compartment. The aim of the present work was to optimize a protocol for the generation of parasite-specific memory T cell lines, representative of their in vivo precursor populations and capable of responding to parasite antigens after long-term culture. Accordingly, peripheral blood mononuclear cells (PBMC) from both chronic asymptomatic and cardiac patients, and from non-infected individuals, underwent different in vitro culture and stimulation conditions. Subsequently, cells were tested for their capacity to respond against T. cruzi lysate by measuring [3H]-thymidine incorporation and interferon-γ and GM-CSF secretion. Results allowed us to adjust initial T. cruzi lysate incubation time as well as the number of expansions with phytohemagglutinin (PHA) and irradiated allogeneic PBMC prior to specificity evaluation. Moreover, our data demonstrated that parasite specific T cells displayed a clear and strong activation by using T. cruzi lysate pulsed, Epstein-Barr virus (EBV)-transformed human B lymphocytes (B-LCL), as autologous antigen presenting cells. Under these culture conditions, we generated a clone from an asymptomatic patient's memory CD4+ T cells which responded against epimastigote and trypomastigote protein lysate. Our results describe a culture method for isolating T. cruzi specific T cell clones from patients with Chagas disease, which enable the acquisition of information on functionality and specificity of individual T cells.

MeSH terms

  • Animals
  • Antigen-Presenting Cells / immunology
  • Cell Line, Transformed
  • Chagas Disease / immunology*
  • Chronic Disease
  • Humans
  • Immunologic Memory
  • In Vitro Techniques
  • T-Lymphocytes / immunology*
  • Trypanosoma cruzi / immunology*

Grants and funding

This work was financially supported by the Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET; Grant number 112-200801-02915) and by the Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT; Grant number 2014-1026) to KAG and in part by National Institute of Allergy and Infectious Diseases (NIH-NIAID, Grant number 5R21AI109439-02) to CP. GRA performed part of the experimental work in this article during a stay at TPIMS supported by the Fulbright Program and the Bunge y Born Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.