https://repositorio.ufba.br/handle/ri/20591 Thu, 14 May 2026 15:14:37 GMT 2026-05-14T15:14:37Z https://repositorio.ufba.br/handle/ri/41854 Dinâmica da resposta imunológica em populações de indivíduos expostos à infecção por SARS-CoV-2 submetidos à imunização vacinal ou em evolução para Covid-19 Morais, Isa Rita Brito de Torres, Alex José Leite The clinical spectrum of COVID-19 is quite variable, and may present as asymptomatic, with mild involvement of the upper respiratory tract and progression to severe pneumonia with respiratory failure, failure and even death. The severity of the disease appears to be directly associated with aspects of the patient's immune response, and an efficient assembly of the immune response becomes essential against SARS-CoV-2 infection, demonstrating a significant relationship between the severity of the disease, the expression profile of immune cells and the levels of pro-inflammatory cytokines. Studies suggest that SARS- CoV-2 leads to immune dysregulation, with a storm of pro-inflammatory cytokines, leading to lymphopenia, dysfunctions in lymphocytes, granulocytes and monocytes, causing great tissue destruction and clinical worsening of the patient. Vaccination has been considered the main strategy against the intense spread of the virus and is being administered to millions of individuals worldwide, including in Brazil. This study evaluated the vaccine response of two COVID-19 vaccines, CoronaVac and Pfizer-BioNTech (BNT162b2), before and after vaccine administration, and characterized the immune response in patients with different clinical forms of COVID-19, in different populations. The results showed changes in the cellular and humoral immune response in patients who received both doses, and individuals with the severe clinical form of COVID-19 showed very significant changes in the cellular immune profile. Universidade Federal da Bahia Tese Fri, 12 Jul 2024 00:00:00 GMT https://repositorio.ufba.br/handle/ri/41854 2024-07-12T00:00:00Z https://repositorio.ufba.br/handle/ri/40498 Células mesenquimais estromais e Fator de crescimento derivado de plaquetas: caracterização e potencial terapêutico em lesões associadas à doença falciforme Ribeiro, Tiago Oliveira Fortuna, Vitor Antonio Osteonecrosis and leg ulcers are tissue injuries associated with microvascular complications commonly found in patients with sickle cell disease (SCD). Since these comorbidities have limited treatment options, the use of mesenchymal stromal cells or growth factors may be an effective therapeutic approach for treating osteonecrosis and chronic leg ulcers in patients with sickle cell disease, improving clinical outcomes and accelerating tissue healing. This study aimed to quantify the population of mesenchymal stromal cells in bone marrow samples from patients with SCD and osteonecrosis and compare it with patients with osteoarticular complications not related to SCD, as well as to investigate the effects of human recombinant PDGF-BB (rh-PDGF) on the wound healing process in a murine model of SCD. Our first study revealed that the population of CD271+CD45-/low mesenchymal stromal cells was higher in both the total aspirate and the bone marrow mononuclear cell concentrate in patients with SCD and osteonecrosis compared to patients with osteoarticular complications not related to SCD. We demonstrated a significant correlation (r = 0.7483; p = 0.0070) between the number of CD271+CD45-/low cells and the colony-forming unit-fibroblast (CFU-F) count in vitro in samples from SCD patients. Our data revealed that the application of PDGF-BB contributed to greater wound closure on day 3 post-injury (46.71 ± 3.87%) vs (33.82 ± 2.72%) in wounds treated with PBS. Wounds treated with PDGF showed greater collagen deposition and an increase in the number of blood vessels and perivascular cells on day 3 post-injury. However, there was a higher presence of inflammatory infiltrate in PDGF-treated wounds, corroborating the elevated levels of pro-inflammatory mediators found in gene expression analyses. In conclusion, these studies demonstrate the promising potential of applying mesenchymal stromal cells and growth factors in the treatment of microvascular complications related to sickle cell disease. Universidade Federal da Bahia Tese Mon, 11 Jul 0007 00:00:00 GMT https://repositorio.ufba.br/handle/ri/40498 0007-07-11T00:00:00Z https://repositorio.ufba.br/handle/ri/40148 Toxocaríase: soroprevalência, fatores de risco e avanços no imunodiagnóstico com proteínas quiméricas recombinantes Silva, Raphael Chagas Pinheiro, Carina da Silva Introduction: Human toxocariasis is among the most neglected helminthic diseases worldwide. Infections by Toxocara spp. are associated with risk factors to which individuals are exposed. Diagnosis of the infection is typically performed through ELISA using excretory-secretory antigens of Toxocara spp. as the gold standard; however, cross-reactivity and variation in precision parameters are some disadvantages of this test. Objective: This study aimed to determine the seroprevalence of toxocariasis in a prospective study (2005-2013); assess the associated risk factors; and produce recombinant chimeric proteins for use in immunodiagnostics. Sera from 926 participants in the SCAALA epidemiological follow-up (2005 and 2013) were immunodiagnosed using indirect ELISA, and associations of the infection with clinical and sociodemographic aspects of the individuals were evaluated. Chimeric proteins (rSHORT and rFULL), based on B-cell epitopes, were expressed and used in the immunodiagnosis of toxocariasis in 232 sera from the Salvador Asthma and Rhinitis Control Program. Results: The prevalence of anti-Toxocara IgG antibodies was 48% in 2005 and 53% in 2013, with 25% of new cases occurring in 2013. Increasing age and exposure to pets were consistent risk factors, while higher maternal education and living on paved streets were protective factors. Positive individuals showed a negative correlation with Skin Prink Test reactivity, while elevated levels of IL-10 and eosinophils in both years were positively associated. The rSHORT protein showed sensitivities of 98.6% and 99.3% in adsorbed and non-adsorbed sera, respectively, while in specificities it reached 94.4% and 97.8%. The rFULL protein showed sensitivities of 93.7% and 89.4%, respectively, and specificities of 86.7% and 81.1%. Conclusion: The infection patterns of Toxocara spp. in our study population were primarily linked to the third age group (≥8 years old) and the presence of cats or dogs at home. Elevating maternal education levels alongside improved housing conditions also emerged as significant factors in mitigating Toxocara spp. infection. Both in Dot Blot and indirect ELISA, the rSHORT protein used as an antigen in the immunodiagnosis of toxocariasis showed superior and more results that are reliable compared to the rFULL protein. Comparatively to TES-26 and CTL-4 molecules, the rSHORT protein demonstrated greater potential to be used as an alternative antigen in the immunodiagnosis of toxocariasis. Universidade Federal da Bahia Tese Thu, 23 May 2024 00:00:00 GMT https://repositorio.ufba.br/handle/ri/40148 2024-05-23T00:00:00Z https://repositorio.ufba.br/handle/ri/39962 Perfil da microbiota intestinal em indivíduos asmáticos e seu papel imunomodulador Fiuza, Bianca Sampaio Dotto Figueiredo, Camila Alexandrina Viana de The phenomenon of dysbiosis in the intestinal microbiome can influence the host's immune development and the incidence of allergic diseases. It is believed that microbiome-host interactions, i.e., symbiosis, contribute to the proper development of the immune system, while microbial dysbiosis has been associated with a variety of inflammatory disorders, including asthma. The aim of this study is to characterize the taxonomic profile of the intestinal microbiota in asthmatic individuals participating in the World Asthma Phenotypes (WASP) and associate it with related immunomodulatory mechanisms. The assessment of the intestinal microbiota was conducted through sequencing the V4 region of the 16S rRNA gene from bacterial DNA extracted from stool samples, followed by bioinformatic analysis using the QIIME2 software. Association with the immune response was investigated using markers such as skin prick test positivity, induced sputum cellularity, and cytokine levels in nasal lavage. Although all predominant phyla, such as Tenericutes, Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, were consistent between asthmatics and non-asthmatics, differences in relative abundances were observed. No significant differences in bacterial richness or diversity were identified between asthmatics and non-asthmatics based on alpha diversity. However, a statistically significant dissimilarity in beta diversity was observed. The genus Bacteroides was the most abundant, contributing to the dissimilarity within the asthmatic group, while Prevotella was more prevalent in non-asthmatics. The presence of Bacteroides in the microbiota of asthmatics correlated with IL-4 production in nasal lavage. These results reinforce the understanding of differences in the microbial community between asthmatic and non-asthmatic individuals. Universidade Federal da Bahia Tese Mon, 05 Feb 2024 00:00:00 GMT https://repositorio.ufba.br/handle/ri/39962 2024-02-05T00:00:00Z