Banca de DEFESA: LUANA EVANGELISTA DE ARAÚJO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LUANA EVANGELISTA DE ARAÚJO
DATE: 13/06/2022
TIME: 09:00
LOCAL: IGM Sala Virtual 5
TITLE:

Detection of serum antibodies to lipid extracts of Mycobacterium tuberculosis

KEY WORDS:

Tuberculosis, Lipids, Serological tests.

PAGES: 57
BIG AREA: Ciências Biológicas
AREA: Imunologia
SUMMARY:

ABSTRACT
INTRODUCTION: Tuberculosis (TB), a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb), is considered a serious public health problem. About 40% of the dry weight of the Mtb wall is composed of lipids. Much of the bacterial genome is dedicated to the biosynthesis and degradation of these molecules. Mtb contains transporters which are involved in the import of these lipids through the cell wall that are encoded by the mce 1 to 4 operons. In a recent study, it was demonstrated in an in vitro model that Mtb, by repressing the expression of the mce1 operon, is capable of modifying the lipid composition of its cell wall accumulating free mycolic acids. Another study demonstrated that Mtb lipids have a distinct ability to activate the pro-inflammatory response in murine macrophages and in human T cells. Thus, as they are important molecules for the virulence of the bacillus and because they are also capable of stimulating a cellular immune response in the host, in this dissertation, we explore whether Mtb lipids are capable of stimulating a humoral response with the production of immunoglobulins (Igs) that can be detected in human serum in different populations. AIM: To evaluate the levels of IgG and IgM responsive to lipid extracts of Mtb virulent wild-type strain and the mutant in the mce1 operon, in addition to identifying whether these Igs can be explored as possible markers of tuberculosis disease and infection. MATERIAL AND METHODS: Volunteers were invited to participate in a cross-sectional study by signing an informed consent form (ICF). Sera from these individuals were collected and stored at -80ºC until use. ELISA assays were performed to identify the detection of IgG and IgM antibodies against the lipid extracts of Mtb adsorbed on plates. The evaluation of the levels of these Igs was carried out through the reactivity index (RI), geometric mean and confidence interval (CI) of 95%, in addition some performance parameters of the tests were evaluated as ROC curve, sensitivity, specificity, accuracy, among others. RESULTS: It is observed that the clinical and demographic characteristics of the groups selected for the study are very similar. The tests carried out demonstrate that there is no significant difference in the antibody dosage between the groups stimulated by Mtb lipid extracts of both strains, with the exception of IgG and IgM levels stimulated by the lipids of the wild type, in the group of individuals with other pulmonary diseases (OPD) in relation to the others. CONCLUSION: The lipid extracts of Mtb showed limited ability to differentiate the groups tested in the study by the dosages of IgG and IgM. However, an increase in antibody titers responsive to Mtb lipid extracts was observed in the ODP group, which can be explored as a differential screening test. In addition, further studies should be carried out seeking to assess the role of lipid species isolated from Mtb as possible markers of prognosis or diagnosis of the disease, as a way of increasing the sensitivity and specificity of the tests.

BANKING MEMBERS:
Interna - 2573399 - DEBORAH BITTENCOURT MOTHE FRAGA
Externa à Instituição - LUKARY OLIVEIRA TAKENAMI - UNIVASF
Presidente - 222.573.739-87 - SÉRGIO MARCOS ARRUDA - UFBA