Molecular Characterization of Tc964, A Novel Antigenic Protein from
Authors: Gabriela Delgado
C√©sar Augusto Ram√≠rez
Jos√© Mar√≠a Requena
Concepci√≥n J Puerta
Paulino G√≥mez-Puertas
Elizabeth Ruiz-M√°rvez
Fanny Guzm√°n
Eliana Roc√≠o Rodr√≠guez
Magda Mellisa Fl√≥rez
Journal: International journal of molecular sciences (2020)
Discipline: CHEMISTRY
Keywords: Leishmania major; Trypanosoma cruzi; chagas disease; leishmaniasis; molecular modelling
Affiliations: Grupo de Investigaci√≥n en Enfermedades Infecciosas, Departamento de Microbiolog√≠a, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 # 40- 62, Bogot√°, Colombia., Grupo de Investigaci√≥n en Inmunotoxicolog√≠a, Departamento de Farmacia, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 # 45-01, Bogota, Colombia., N√∫cleo de Biotecnolog√≠a Curauma (NBC), Pontificia Universidad Cat√≥lica de Valparaiso, Avenida Universidad, Curauma, Valparaiso 2373223, Chile., Grupo de Modelado Molecular del Centro de Biolog√≠a Molecular Severo Ochoa, Microbes in Health and Welfare Department, Universidad Aut√≥noma de Madrid (CBMSO, CSIC-UAM), 28049 Madrid, Spain., Grupo Regulaci√≥n de la Expresi√≥n G√©nica en Leishmania del Centro de Biolog√≠a Molecular Severo Ochoa, Molecular Biology Department, Universidad Aut√≥noma de Madrid (CBMSO, CSIC-UAM), 28049 Madrid, Spain.

Abstract:  The Tc964 protein was initially identified by its presence in the interactome associated with the LYT1 mRNAs, which code for a virulence factor of Trypanosoma cruzi. Tc964 is annotated in the T. cruzi genome as a hypothetical protein. According to phylogenetic analysis, the protein is conserved in the different genera of the Trypanosomatidae family; however, recognizable orthologues were not identified in other groups of organisms. Therefore, as a first step, an in-depth molecular characterization of the Tc946 protein was carried out. Based on structural predictions and molecular dynamics studies, the Tc964 protein would belong to a particular class of GTPases. Subcellular fractionation analysis indicated that Tc964 is a nucleocytoplasmic protein. Additionally, the protein was expressed as a recombinant protein in order to analyze its antigenicity with sera from Chagas disease (CD) patients. Tc964 was found to be antigenic, and B-cell epitopes were mapped by the use of synthetic peptides. In parallel, the Leishmania major homologue (Lm964) was also expressed as recombinant protein and used for a preliminary evaluation of antigen cross-reactivity in CD patients. Interestingly, Tc964 was recognized by sera from Chronic CD (CCD) patients at different stages of disease severity, but no reactivity against this protein was observed when sera from Colombian patients with cutaneous leishmaniasis were analyzed. Therefore, Tc964 would be adequate for CD diagnosis in areas where both infections (CD and leishmaniasis) coexist, even though additional assays using larger collections of sera are needed in order to confirm its usefulness for differential serodiagnosis. 

Retracted: No

PubPeer comments:
 # No B-cell epitope mapping information in this paper The authors characterize a novel antigen from Trypanosoma cruzi (Chagas Disease). However, in spite of saying (in the Abstract) that  B-cell epitopes were mapped , the authors do not provide any information regarding the sequence of the epitopes, or the sequences of the TcNV and TcKP synthetic peptides used to map antigenic regions within the Tc964 antigen. It is sad that in spite of having 3 reviews, reviewers have failed to see this. Reviewer #2 naively trusted the authors and say that  B-cell epitopes were mapped , just repeating a statement made in the Abstract without checking in the manuscript for the evidence. [see reviewer reports here][https: www.mdpi.com 1422-0067 21 7 2432 review_report), https: www.mdpi.com 1422-0067 21 7 2432 review_report. It would be nice if the authors could highlight the antigenic regions indentified in the Tc964 antigen, and provide the sequences of the TcNV and TcKP peptides. ,