Prediction of Conserved Peptides of Paracoccidioides for Interferon-γ Release Assay: The First Step in the Development of a Lab-Based Approach for Immunological Assessment during Antifungal Therapy.

Sarah Brena Aparecida Rosa,Anamaria Mello Miranda Paniago,Bárbara Guimarães Csordas,Sandra Maria Do Valle Leone De Oliveira,James Venturini,Amanda Ribeiro Dos Santos

doi:10.3390/jof6040379

Abstract

Impaired antigen-specific cell-mediated immunity (CMI) is a primary immunological disturbance observed in individuals that develop paracoccidioidomycosis (PCM) after exposure to Paracoccidioides spp. Restoration of Paracoccidioides-specific CMI is crucial to stop the antifungal treatment and avoid relapses. A convenient and specific laboratory tool to assess antigen specific CMI is required for the appropriate clinical treatment of fungal infections, in order to decrease the time of antifungal therapy. We used an interferon-γ release assay strategy, used in the diagnosis of latent tuberculosis infection, to address our aims in this study. Information on proteins secreted by two well-studied representative strains—Paracoccidioides brasiliensis (Pb18) and P. lutzii (Pb-01)—were explored using PubMed or MEDLINE. From 26 publications, 252 proteins were identified, of which 203 were similar according to the Basic Local Alignment Search Tool. This enabled a selection of conserved peptides using the MEGA software. The SignalP-5.0, TMHMM, IEDB, NetMHC II, and IFNepitope algorithms were used to identify appropriate epitopes. In our study, we predicted antigenic epitopes of Paracoccidioides that could bind to MHC class II and induce IFN-γ secretion. These T cell epitopes can be used in the development of a laboratory tool to monitor the CMI of patients with PCM.

Highlights

Paracoccidioidomycosis (PCM) is a systemic mycosis endemic to Latin America and is caused by fungi belonging to the genus Paracoccidioides [1]
Of the 150 articles, 25 containing information on the identity of the extracted amino acid sequences in GenBank corresponding to P. brasiliensis and P. lutzii were included; these included articles that described yeast proteins obtained from preparations of fungal culture, plasma, or peripheral blood mononuclear cells without the intervention of any drugs
Comparing the epitopes of ESAT-6 with the ones we found, the highest coverage of class II MHC was noted for the highest-class coverage percentage of 0% and

Summary

Introduction

Paracoccidioidomycosis (PCM) is a systemic mycosis endemic to Latin America and is caused by fungi belonging to the genus Paracoccidioides [1]. Based on studies of nuclear and mitochondrial genealogy, five species of Paracoccidioides—P. brasiliensis, P. lutzii, P. americana, P. restripiensis, and P. venezuelensis—are reportedly responsible for PCM [2]. P. brasiliensis and P. lutzii are the primary representative species used in clinical, molecular, morphological, and immunological studies on fungi–host interplay, with the findings having implications in laboratory diagnosis [1,3]. J. Fungi 2020, 6, 379; doi:10.3390/jof6040379 www.mdpi.com/journal/jof.

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