Banca de DEFESA: JOANA LARISSA VICENTE DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOANA LARISSA VICENTE DA SILVA
DATE: 20/04/2026
TIME: 09:00
LOCAL: https://meet.google.com/iwf-qosm-kge
TITLE:

GENETIC CHARACTERIZATION OF THE CHIKUNGUNYA VIRUS CIRCULATING IN THE STATE OF
RIO GRANDE DO NORTE (2022–2025): EVOLUTIONARY, STRUCTURAL AND IMMUNOINFORMATICS ANALYSIS

 

 

KEY WORDS:

Chikungunya; molecular evolution; phylogeny; mutations;
immunoinformatics; structural modeling; ECSA.

 

PAGES: 75
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

The Chikungunya virus (CHIKV), a member of the family Togaviridae and the genus
Alphavirus, has maintained continuous circulation in the state of Rio Grande do Norte (RN), Brazil, since its
introduction in 2014. Given the scarcity of recent studies addressing viral genetic diversity in the region, this study
aimed to perform a phylogenetic characterization of CHIKV circulating in RN between 2022 and 2025, identify
relevant structural mutations, evaluate potential immunological implications associated with the detected
substitutions, and conduct predictive structural modeling to spatially localize the identified alterations. A total of 154
E1 gene sequences and 51 structural polyprotein sequences (E3–E2–6K–E1), retrieved from public databases and
subjected to strict quality curation, were analyzed using phylogenetic, mutational, immunoinformatic, and predictive
structural modeling approaches. Maximum Likelihood phylogenetic analyses demonstrated that all samples belong to the East-Central-South African (ECSA) genotype, forming a consistent monophyletic cluster compatible with local maintenance and ongoing endemic transmission. Sequences from 2025 grouped within a cohesive subclade,
suggesting recent circulation of a regionally derived lineage. Mutational analysis identified ten amino acid
substitutions predominantly distributed in glycoproteins E1 and E2, including A98T, recurrent between 2022 and
2023; K211T, detected across multiple years; I317T, characterized as an emergent mutation in 2025; and N214S,
classified as transient. Immunoinformatic analyses indicated quantitative preservation of the predicted epitope
repertoire for MHC class I and II molecules throughout the analyzed period, although a qualitative substitution
pattern was observed in MHC class I epitopes, involving loss and emergence of specific predicted peptides. Prediction
of linear B-cell epitopes revealed conservation of potentially antigenic regions in glycoprotein E2, consistent with
relative stability of the theoretical antigenic profile. Structural modeling was employed to spatially contextualize the
identified mutations within E1 and E2 proteins. Overall, the findings indicate limited structural diversification of CHIKV
in RN between 2022 and 2025, with maintenance of the ECSA lineage and occurrence of point mutations without
evidence of broad remodeling of the predicted immunogenic repertoire. These results reinforce the importance of
continuous genomic surveillance for monitoring viral evolution and understanding regional transmission dynamics.

 

 

COMMITTEE MEMBERS:
Interna - 1346635 - JANEUSA TRINDADE DE SOUTO
Externo ao Programa - 2985070 - JONAS IVAN NOBRE OLIVEIRA - nullPresidente - 1715230 - JOSELIO MARIA GALVAO DE ARAUJO
Externo à Instituição - THALES ALLYRIO ARAUJO DE MEDEIROS FERNANDES - UERN