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Master's Dissertation
DOI
https://doi.org/10.11606/D.60.2022.tde-19072023-144204
Document
Author
Full name
Rayane Valezi Gonçalves
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2022
Supervisor
Committee
Russo, Elisa Maria de Sousa (President)
Ferreira, Beatriz Rossetti
Freire, Caio César de Melo
Title in Portuguese
Identificação de epítopos de papilomavirus humano 16 e 18 ativadores de células T CD4+ e T CD8+ candidatos ao desenvolvimento de vacina terapêutica, uma abordagem in silico
Keywords in Portuguese
Epítopos
HPV
Imunoinformática
Vacina
Abstract in Portuguese
O Papilomavírus Humano provoca lesões pré-cancerosas no epitélio cervical, podendo evoluir para um câncer cervical, considerado o quarto tipo de câncer mais comum entre mulheres mundialmente. Embora existam vacinas profiláticas disponíveis no Sistema Único de Saúde (SUS), a eficácia foi comprovada apenas em quem ainda não havia sido exposto ao vírus. O uso de vacinas com as oncoproteínas E6 e E7 já se mostrou promissor na redução das lesões causadas por HPV. Baseado em vacinologia reversa, identificou e selecionou epítopos das proteínas E6 e E7 de HPV16 e HPV18, capazes de ativar as células CD4 e CD8. Usando a abordagem imunoinformática, as sequências de aminoácidos foram selecionadas de um banco de dados, e a identificação de epítopos foi realizada com base na afinidade de ligação ao complexo principal de histocompatibilidade (MHC) II e MHC I. Esses epítopos foram filtrados por ferramentas que avaliam antigenicidade, alergenicidade, toxicidade e afinidade entre complexo e receptor da célula T. Linkers foram anexados a cada peptídeo para clivagem e cada um foi analisado usando docking computacional (CD) para avaliar a energia de ligação. Os que se enquadraram nos parâmetros favoráveis foram avaliados em conservação e cobertura populacional. Utilizando as ferramentas imunoinformáticas, selecionamos seis epítopos de E6 e quatro epítopos E7 do HPV16, quatro epítopos E6 e sete epítopos E7 do HPV18, ambos com afinidade MHC II. Para o MHC I, foram selecionados quatro epítopos E6 e dois epítopos E7 do HPV16, bem como três epítopos E6 e dois epítopos E7 do HPV18. O docking computacional encontrou as melhores energias de ligação entre o Antígeno Leucocitário Humano (HLA) e os epítopos, ajudando no refinamento da seleção. Conservação e cobertura populacional confirmaram o melhor conjunto de epítopos. Ainda que as metodologias in sílico possam prever as respostas citotóxicas e das células T auxiliares, numerosos processos complexos estão envolvidos na resposta imunológica humana e, por isso, são necessários mais testes para confirmar essas previsões. Essa coleção de epítopos selecionada pode resultar numa vacina terapêutica de multiepítopos capaz de reduzir as lesões pré-cancerosas e ajudar a eliminação da infecção por HPV.
Title in English
Identification of human papillomavirus 16 and 18 epitopes activating CD4+ and CD8+ T cells candidates for therapeutic vaccine development, an in silico approach
Keywords in English
Epitopes
HPV
Immunoinfomatic
Vaccine
Abstract in English
The Human Papillomavirus can induce precancerous lesions in the cervical epithelium, which can evolve into cervical cancer, considered the world's fourth most common cancer among women. Although there are prophylactic vaccines available on Sistema Único de Saúde (SUS), Brazil's public health-care system, the effectiveness has been proven only in those not previously exposed to the virus. The use of vaccines with the oncoproteins E6 and E7 has already been demonstrated. Based on reverse vaccinology, this project intended to identify and select epitopes of E6 and E7 HPV16 and HPV18 proteins capable of CD4 and CD8 cells activation. Using immunoiformatic approach, the amino acids sequences were selected from a data bank, and the epitopes identification, based on bind-affinity for the Major Histocompatibility Complex (MHC) II and MHC I, was realized. These epitopes were filtered with immunoinformatic tools that measure antigenicity, allergenicity, toxicity, and complex affinity to T cell receptors. A sequence of amino acids linkers was attached to each peptide on the linkers' cleavage point, and each peptide was then analyzed by computational docking (CD) for ligand energy evaluation. Those suited to the CD expected parameters were measured for conservancy and population coverage. Using the immunoinformatic tools, we selected 6 E6 epitopes and 4 E7 epitopes from HPV16 with MHCII affinity, 4 E6 epitopes, and 7 E7 epitopes from HPV18. For MHCI, 4 E6 epitopes, and 2 E7 epitopes from HPV16, and 3 E6 epitopes and 2 E7 epitopes from HPV18 were selected. The computational docking shows the best energy ligation between HLA and the epitopes, helping in the selection refinement. Conservancy and populational coverage confirmed the best set of epitopes. Although in silico methodologies can make predictions of cytotoxic and helper T cell response, a lot of complex processes are involved in human immunologic response and more tests are needed to confirm predictions. Our expectation is to test the epitopes selected to be used, in the future, in a therapeutic multi-epitopes vaccine capable to reduce the precancerous lesions and help the elimination of HPV infection.
 
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Release Date
2024-06-27
Publishing Date
2023-08-21
 
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