Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Botany Microbiology

Mycobacterium tuberculosis (Mtb) is the causative agent of pulmonary tuberculosis (PTB), a global public health problem and a source of preventable deaths each year, with 8.8 million new cases of TB and 1.5 million deaths annually. Approximately, 10% of infected individuals develop pulmonary or extrapulmonary TB, suggesting that host genetic factors play a significant role in disease resistance/susceptibility by altering immunity against MTB. Toll-like receptors (TLRs) are known to play important roles in human innate immune systems. Polymorphisms in and functions of TLRs have been investigated to identify associations with specific infectious diseases including TB. TLRs are a family of transmembrane receptors, which play a key role in both innate and adaptive immune responses. Beside of recognizing specific molecular patterns that associated with different types of pathogens. Activating TLRs lead to the heightened expression of various inflammatory genes, which have a protective role against infection. Toll-like receptor 9 (TLR9) is a pattern recognition receptor that mediates recognition of Mtb and modulates Mtb-specific T-cell responses. In this study, using a case-population design, the association of single nucleotide polymorphisms (SNPs) in the TLR9 gene region with susceptibility to TB was evaluated. This study was performed for 166 samples of unrelated individual's diagnosis of pulmonary tuberculosis and 98 household healthy samples. Genomic DNA was extracted from EDTA-anticoagulated peripheral blood. The alleles of (rs352140) TLR9 gene polymorphisms were detected using polymerase chain reaction restriction fragment length polymorphism. The resulting fragments were separated in 3% agarose gel electrophoresis

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