https://repositorio.ufba.br/handle/ri/11273 Fri, 15 May 2026 22:00:57 GMT 2026-05-15T22:00:57Z https://repositorio.ufba.br/handle/ri/44161 Marcadores histológicos de cronicidade e progressão na glomeruloesclerose segmentar e focal Silva, José Nathan Andrade Muller da Santos, Washington Luís Conrado dos Segmental and focal glomerulosclerosis not otherwise specified (FSGS NOS) is a glomerulopathy with undefined outcome. We reviewed possible histopathological markers of chronicity from the literature and identified 33 cases of FSGS NOS for our sample. Based on the frequency of certain markers, we developed an experimental scoring system that uses tubular atrophy, interstitial fibrosis, glomerular hyalinosis, arteriolosclerosis, and glomerular sclerosis. We applied an experimental scoring system to predict chronicity. Our analysis revealed a sensitivity of 0.66 and a specificity of 0.80. Glomerular hyalinosis emerged as the most reliable isolated parameter, with a sensitivity of 0.83 and a specificity of 0.70. We obtained a survey of risk mutation of APOL1 genes from 25 of 33 patients. Additionally, we conducted our specimen in scanning for future endeavors in digital pathology for AI training. Universidade Federal da Bahia Dissertação Fri, 24 Jan 2025 00:00:00 GMT https://repositorio.ufba.br/handle/ri/44161 2025-01-24T00:00:00Z https://repositorio.ufba.br/handle/ri/43888 Avaliação do papel do gene lpg2 durante infecção de macrófagos por Leishmania amazonensis Goicochea, Astrid Madeleine Calero Borges, Valéria de Matos INTRODUCTION: Leishmaniasis is a disease caused by protozoa of the genus Leishmania, belonging to the Trypanosomatidae family, and remains a significant public health problem in several regions of the world, including Brazil. Leishmania amazonensis is the main species associated with diffuse cutaneous leishmaniasis (DCL), although it is also involved in cases of localized cutaneous leishmaniasis (LCL). Our group has been investigating inflammatory mechanisms triggered by surface glycoconjugates of promastigotes, such as lipophosphoglycan (LPG) and other phosphoglycans (PPGs). Strategies based on parasites deficient in these molecules have been fundamental to understanding their role during infection. OBJECTIVES: This study aimed to investigate the contribution of the lpg2 gene to the early stages of the host-parasite interaction and the survival of L. amazonensis in murine macrophages. METHODS: Bone marrow-derived macrophages from C57BL/6 mice were infected with wild-type (WT) or lpg2-deficient (Δlpg2) L. amazonensis promastigotes. A 5:1 (parasite: macrophage) ratio was used for the assays. RESULTS: Δlpg2 parasites showed a significant reduction in intracellular parasite load and viability compared to the WT strain. In the early moments of infection, Δlpg2 parasites preferentially entered through the cell body, whereas WT parasites predominantly interacted via the flagellar tip. Mutants also exhibited greater colocalization with acidified intracellular compartments and increased production of reactive oxygen species (ROS), with no significant differences in nitrite levels, an indirect marker of nitric oxide (NO) production. CONCLUSION: The results indicate that the lpg2 gene of L. amazonensis is crucial for the success of infection in C57BL/6 macrophages, since its absence compromises parasite viability during the interaction with the host cell. Universidade Federal da Bahia Dissertação Fri, 15 Aug 2025 00:00:00 GMT https://repositorio.ufba.br/handle/ri/43888 2025-08-15T00:00:00Z https://repositorio.ufba.br/handle/ri/43879 Mapeamento de epítopos e produção de proteínas quiméricas como estratégia para o desenvolvimento de uma vacina multiepítopo contra Schistosoma mansoni Khouri, Mariana Ivo Farias, Leonardo Paiva Schistosomiasis is an endemic disease in 78 countries and presents the highest morbidity among helminth infections. Therefore, an effective vaccine against this disease would be a valuable addition to current control strategies and, ultimately, to its elimination. Most vaccines investigated to date have been based on single antigens, and none have reached the final stages of development. We believe that using multiple immunogenic epitopes associated with protective immune responses represents a more promising approach for developing an effective vaccine. It is possible to identify protection-associated epitopes in murine models immunized with attenuated cercariae and in self-curing rhesus macaques. Additionally, in endemic areas, some individuals develop resistance to reinfection after multiple treatments with praziquantel (PZQ). This thesis is divided into four chapters. In Chapter 1, a systematic review was conducted using articles indexed in PubMed, totaling 396 studies evaluated with respect to various aspects of vaccine development against schistosomiasis. It was observed that the emergence of new technologies has significantly impacted preliminary studies in animal models. The majority of published studies used S. mansoni, with over 80% employing mice as the animal model. Furthermore, most of the proteins evaluated originated from the parasite’s tegument. In Chapter 2, epitope mapping was performed in rhesus macaques experimentally infected with S. mansoni. The animals were classified as high or low responders according to the rate of parasite clearance. Subsequently, sera from these animals were used in peptide microarray assays targeting proteins at the parasite–host interface (tegument, esophageal gland, and gut lining). The targeted epitopes were similar between the groups; however, the intensity of the immune response was greater in high responders. Overall, animals exhibited a stronger response against gastrointestinal tract-associated antigens. Based on these findings, 18 candidate epitopes were selected for further analysis. In Chapter 3, a convenience study was conducted in the endemic region of Conde-BA, involving individuals classified as resistant to reinfection (RR) and susceptible to reinfection (SR) after PZQ treatment. Serological analysis revealed that RR individuals had significantly higher levels of IgG1 against tegumental membrane extract (SmTEG). Epitope mapping using microarrays identified three epitopes preferentially recognized by the RR group, located in the tegumental proteins Sm25 and ADP- ribosyl cyclase. When compared to animal models (mice immunized with attenuated cercariae and infected rhesus macaques), 4 shared epitopes were identified across all approaches, which warrant further investigation. In Chapter 4, three chimeric proteins were designed (P1 – Esophageal gland, P2 – Tegument, P3 – Gastrodermis) each containing epitopes previously mapped in the murine model immunized with attenuated cercariae. The proteins were expressed recombinantly and purified via nickel affinity chromatography. P1 yielded the highest production, while P2 exhibited the highest purity. Initially, these proteins were used to immunize BALB/c mice, aiming to generate polyclonal antibodies through hybridoma production. P1 induced the greatest number of positive clones, while P2 and P3 yielded fewer. Sera from immunized animals were able to recognize native parasite proteins, as demonstrated by immunohistochemistry assays. The next step will involve functional evaluation of these polyclonal antibodies against schistosomula in vitro. Finally, an immunization and challenge assay were conducted in C57BL/6 mice, which received three doses of the chimeric proteins (administered individually or in combination), formulated with Alum as an adjuvant. After 21 days, the animals were challenged with S. mansoni. A robust IgG1 response against the proteins was observed. The group immunized with P1 showed a significantly higher ratio of IgG1 response compared to IgG2c, especially when compared to the P3 and pool groups. There was a trend of reduced parasitic load across all groups. Group P1 showed a significant reduction in egg count and female fecundity, while Group P2 exhibited a significant reduction in the adult worm burden. Therefore, we intend to further investigate the protective potential of these proteins. Universidade Federal da Bahia Tese Fri, 27 Jun 2025 00:00:00 GMT https://repositorio.ufba.br/handle/ri/43879 2025-06-27T00:00:00Z https://repositorio.ufba.br/handle/ri/43865 Avaliação do potencial terapêutico de vesículas extracelulares derivadas de células-tronco mesenquimais de cordão umbilical humano em modelo experimental de dermatite atópica em camundongos Daltro, Sérgio Ricardo Teixeira Soares, Milena Botelho Pereira Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by eczematous lesions and intense pruritus, posing a significant public health challenge. Conventional therapies, primarily based on corticosteroids and immunosuppressants, have limited efficacy and are associated with significant adverse effects. The therapeutic use of mesenchymal stem cells (MSCs) or their secretome, including extracellular vesicles (VEs), has shown promising immunomodulatory effects in the treatment of immune-mediated diseases. In this study, the therapeutic potential of VEs derived from human umbilical cord MSCs was evaluated in BALB/c mice with atopic dermatitis induced by epicutaneous application of 2,4-dinitrochlorobenzene (DNCB). MSCs were isolated, characterized, and used to obtain VEs through ultracentrifugation. VEs were characterized by size, polydispersity index, zeta potential, and morphology using transmission electron microscopy. The results demonstrated that VEs significantly reduced inflammatory markers, such as the number of mast cells, epidermal thickness and pro-inflammatory cytokines IL-4 and TSLP, in addition to promoting the recovery of skin barrier integrity, evidenced by an increase in lipids in the stratum corneum. Histological analysis revealed superior epidermal organization in the treated groups, while clinical evaluation indicated significant improvement in lesions. In an in vitro model of keratinocyte activation, VEs modulated the gene expression of several genes associated with AD. The therapeutic effects observed were comparable to those of dexamethasone, establishing VEs as effective immunomodulatory agents. The findings underscore the potential of VEs derived from MSCs in the treatment of atopic dermatitis, offering an innovative and promising approach with a lower risk of adverse effects. Universidade Federal da Bahia Tese Tue, 04 Feb 2025 00:00:00 GMT https://repositorio.ufba.br/handle/ri/43865 2025-02-04T00:00:00Z