Full text
| |
| Author(s): |
Cleison Ledesma Taira
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) |
| Defense date: | 2019-08-23 |
| Examining board members: |
Carlos Pelleschi Taborda;
Leila Maria Lopes Bezerra;
Benedito Correa;
Elaine Guadelupe Rodrigues
|
| Advisor: | Carlos Pelleschi Taborda |
| Abstract | |
Histoplasma capsulatum is a thermodymorphic fungus, found ubiquitously in nature. Endemic regions include the valleys of the Ohio River and Mississippi (USA), Central America and South America; in Brazil disease cases and microepidemias have been described more frequently in the southeast region. M antigen is a glycoprotein found in the wall of the fungus and induces immune response in both acute and chronic phases of the disease. The characterization of the M antigen as vaccine candidate has not yet been performed and it is of great importance the evaluation and identification of epitopes that can generate new tools for use in the prevention of histoplasmosis. In this work, peptides from in silico analysis of protein antigen M sequence, with the theoretical ability to bind and be presented by MHC class II molecules of C57BL/6 mice, were synthesized. Twelve of the sequences generated were selected and synthesized, among which three (peptides 6, 10 and 12) showed promising results in the prophylactic immunization of mice against histoplasmosis, reducing the fungal load in the lungs and producing cytokines with Th1 response profile (peptide 12) and Th17 response profile (peptide 10 and 12) in animals challenged with sublethal inoculum of the fungus. Also, nine peptide sequences of H. capsulatum (naturally processed and presented) were identified by mass spectrometry from yeast-infected macrophages submitted to immunoprecipitation to isolate the MHC-II peptide complexes. We conclude that in silico prediction methodologies are important and useful for the peptide sequences mapping from immunogenic proteins, since three peptides tested showed promising results in the immunization of animals later challenged with fungi; in relation to the immunoproteomics approach for the identification of peptides presented by APC cells after phagocytosis of the fungus, we believe that this technique is promising because the identified peptide sequences were naturally processed and presented, being able to stimulate the TCR and trigger T cells immune response, confirming with in vitro and in vivo tests is still required. (AU) | |
| FAPESP's process: | 14/17293-3 - Epitopes identification of recombinant antigen M for vaccine development against histoplasmosis in murine experimental model |
| Grantee: | Cleison Ledesma Taira |
| Support Opportunities: | Scholarships in Brazil - Doctorate |