Host and Mycobacterium tuberculosis interaction; expression of iNOS and Tbet genes from the host and virulence factors of the bacteria

Abstract

BackgroundTuberculosis is a major health problem, however it is manifested in only 5–10% of the cases. An interaction between the bacteria and host defense determine presenting manifestations or being latent. In this study, this interaction between the host and bacteria is investigated. MethodsBronchoalveolar lavage fluid samples were collected from 14 pulmonary tuberculosis patients and 16 non-tuberculosis individuals, total RNA was extracted and used for cDNA synthesis Expression of cellular genes iNOS, Tbet, and bacterial Ag85B genes were evaluated by TaqMan Real Time PCR. ResultsThe expression of Tbet in non-tuberculosis group was 25,369.96 times more than TB group (p = 0.038). Correlation between iNOS and Ag85B expression in patient group was statistically significant (p = 0.047). Similarly, the negative correlation between Tbet and Ag85B was also significant in the patient group (p = 0.025). ConclusionThe expression of Tbet gene was lower in patients with tuberculosis compared to control group. Given that Tbet is involved in differentiation of T helper and Th1 cells, plays a major role in host defense. The increase of Ag85B and decrease of Tbet genes in active tuberculosis may result in impaired Th1, leading to host immune failure for controlling the infection.