Memory T Cells and Memory Regulatory T Cells in Mycobacterium tuberculosis Infection: An In Vitro Evaluation
Name: LORENZZO LYRIO STRINGARI
Publication date: 20/09/2018
Advisor:
Name |
Role |
|---|---|
| DANIEL CLAUDIO DE OLIVEIRA GOMES | Co-advisor * |
| RODRIGO RIBEIRO RODRIGUES | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| DANIEL CLAUDIO DE OLIVEIRA GOMES | Co advisor * |
| FAUSTO EDMUNDO LIMA PEREIRA | Internal Examiner * |
| FERNANDA GOBBI AMORIM | External Examiner * |
| MARCO CESAR CUNEGUNDES GUIMARÃES | External Examiner * |
| MOISES PALACI | Internal Examiner * |
Pages
Summary: Individuals with MTB latent infection and patients with active pulmonary tuberculosis have lower levels of microbicidal activity when compared to individuals with low reactivity to PPD. This difficulty in dealing with the bacillus is considered a key point during the disease, since the difficulty of eliminating the bacillus can lead to the development of the disease. In the present study, the frequencies of memory cells and regulatory T cells, as well as their subtypes, were analyzed to elucidate the dynamics involved in the response against Mycobacterium tuberculosis. For this purpose, 57 individuals were used, of which 26 had PPD-, 26 PPD+ and 5 patients with active pulmonary tuberculosis. Cultures were performed, of which two were stimulated, one with H37Rv (standard strain), one with OKT3 and last one in which there was no stimulation. Chapter 1 presents the characterization of the frequencies of memory and regulatory cells obtained from 10 PPD-, 10 PPD+ individuals and 5 TB patients. To obtain these frequencies, microcultures were used, of which one was stimulated with H37Rv (standard strain), another with OKT3 and finally an unstimulated one. Data obtained showed a dynamic among the memory cells, mainly in the regulatory T cells, which were analyzed the frequencies of cells aTreg, rTreg and nsTreg, besides the regulatory T cells with characteristics of memory. Access to this information is extremely important to understand how the response to Mtb works and the mechanisms involved in eliminating or controlling the disease. Our results corroborate the hypothesis that a pre-exposure to Mtb followed by sensitization against the pathogen may trigger a higher propensity for the development of latency/disease and that the understanding of this dynamics may be the key to the understanding of the disease. In Chapter 2 the In vitro Microbicidal Assay (EMiv) is described. In this assay, 16 PPD- and 16 PPD+ individuals and a resazurin dye were used. The data obtained were compared with the technique used by Wallis for death assay which had been adapted for the use of Peripheral Blood Mononuclear Cells (PBMC). We have shown that the use of resazurin increases the sensitivity of the test as well as its quickness ("classic" test 3 to 4 weeks), requiring only 24 hours.
