Mycobacterial manipulation of the host cell

Abstract

Phagosome biogenesis, the process by which macrophages neutralize ingested pathogens and initiate antigen presentation, has entered the field of cellular mycobacteriology research largely owing to the discovery 30 years ago that phagosomes harboring mycobacteria are refractory to fusion with lysosomes. In the past decade, the use of molecular genetics and biology in different model systems to study phagosome biogenesis have made significant advances in understanding subtle mechanisms by which mycobacteria inhibit the maturation of its phagosome. Thus, we are beginning to appreciate the extent to which these pathogens are able to interfere with innate immune responses and manipulate defense mechanisms to enhance their survival within the human host cell. Here, we summarize current knowledge about phagosome maturation arrest in infected macrophages and the subsequent attenuation of the macrophage-initiated adaptive anti-mycobacterial immune defenses.

Mycobacteria modulate host epigenetic machinery by Rv1988 methylation of a non-tail arginine of histone H3

“…Several studies have shown examples of how the pathogenic mycobacteria uses its repertoire of proteins to modulate the host cell. Most of these proteins work at the level of cell surface and a few have been shown to interact with the host cell machinery in the cytoplasm 31,32 .…”

“…Most of these proteins are located on the mycobacterial cell surface, while some have been shown to be secreted in to the host cytoplasm 31,32 . The secretion of Rv1988 into the host was beneficial for the mycobacterium as the survival of M. smegmatis, which is known to be cleared very quickly from the macrophage both in vitro and in animal infection studies, was significantly better when it was expressing Rv1988.…”

Mycobacterium bovis Bacillus Calmette-Guérin Secreting Active Cathepsin S Stimulates Expression of Mature MHC Class II Molecules and Antigen Presentation in Human Macrophages

“…t is estimated that one-third of the global population is asymptomatically infected with Mycobacterium tuberculosis (Mtb) 4 and that 10% of infected individuals will develop active tuberculosis (TB) as a result of reinfection or reactivation of an original infection (1). This risk is increased ϳ10-fold in individuals coinfected with HIV (2,3).…”

“…This risk is increased ϳ10-fold in individuals coinfected with HIV (2,3). The intracellular Mtb bacterium has developed sophisticated strategies to persist inside the host macrophage within a vacuole that escapes intracellular killing mechanisms (4,5).…”

Ультрацитохимические Характеристики Некоторых Микобактерий

“…В литературе описаны зернистые, гомогенные, булавовидные, нитевидные и ветвящиеся формы с булавовидными утолщениями на концах, длинные формы в виде грибов (рис. 34) [115]. Форма микобактерий не является постоянной и изменяется под влиянием внешней среды.…”