Immunogenic mapping of potential epitopes from Tc-CTL-1 for the diagnosis of murine toxocariasis

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Gabriela Rodrigues e Fonseca ; Ana Laura Grossi de Oliveira ^[2] ; Ramayana Morais de Medeiros Brito ^[3] ; Marcelo Andreetta Corral ^[4] ; Richard John Ward ^[5] ; Pâmela Aparecida de Lima ^[6] ; José Bryan da Rocha Rihs ^[7] ; Marcelo Eduardo Cardozo ^[8] ; Paula Keiko Sato ^[9] ; Ricardo Toshio Fujiwara ^[10] ; Sergio Vieira dos Santos ^[11] ; Ronaldo Cesar Borges Gryschek ^[12] ; Susana Angelica Zevallos Lescano ^[13]

• Document type: Journal article
• Source: Memórias do Instituto Oswaldo Cruz; v. 120, 2025-03-14.

Abstract

BACKGROUND Toxocariasis is a neglected global zoonosis. The immunological diagnosis has setbacks that hinder further knowledge about its pathology, epidemiology, and public control measures, and lack of financial support and attention prevents innovative research. Although studies on synthetic peptides are common for several infectious pathologies, none evaluated chemically synthetic peptides for toxocariasis diagnosis. OBJECTIVE This study aimed to identify potential synthetic peptides from C-type lectin 1 (Tc-CTL-1) from Toxocara canis. METHODS In silico analyses were made by five B-cell peptide prediction programs, 3-D modelling, BLASTp homology analysis, and signal-peptide identification. SPOT-synthesis was used for epitope mapping and assessed by dot-blot. Sera from non-infected and T. canis, Strongyloides venezuelensis, Ascaris suum, or Schistosoma mansoni-infected animals were used to assess the peptide’s immunogenicity and cross-reactivity. The selection of potential immunogenic epitopes included the most immunogenic peptides with the least cross-reactivity. FINDINGS Fifty-five peptides were selected by in silico analysis. Dot-blot showed intense recognition by anti-Toxocara IgG and cross-reactivity with A. suum-infected mice. Selection criteria identified four epitopes with diagnostic potential. MAIN CONCLUSIONS The findings demonstrate that synthetic peptides should be explored for innovation of toxocariasis diagnosis, and suggest the adaptation of dot-blot using the SPOT-synthesis technique as a potential immunodiagnostic platform. (AU)

• FAPESP's process: 18/23021-7 - T. canis experimental murine infection: IgG subclass antibodies detection by Immunological techniques using native proteins and recombinant cell-free protein system
• Grantee: Susana Angélica Zevallos Lescano
• Support Opportunities: Regular Research Grants