The extra cytoplasmic function sigma factor sigma(E) is essential for Mycobacterium tuberculosis virulence in mice

Area of Science:

• Microbiology
• Immunology
• Pathogenesis

Background:

• Tuberculosis (TB) is a major global health concern caused by Mycobacterium tuberculosis (Mtb).
• Understanding the genetic basis of Mtb virulence is crucial for developing effective control strategies.
• The sigE gene plays a role in Mtb's response to stress and potential contribution to virulence.

Purpose of the Study:

• To investigate the role of the sigE gene in the virulence of Mycobacterium tuberculosis H37Rv.
• To compare the pathogenicity of a sigE mutant strain with the wild-type strain in animal models.

Main Methods:

• Construction and characterization of a sigE mutant of Mtb H37Rv.
• Infection of immunodeficient and immunocompetent mice with the mutant and wild-type strains.
• Histopathological analysis of granuloma formation in infected mice.

Main Results:

• The Mtb sigE mutant was significantly attenuated in both immunodeficient and immunocompetent mouse models.
• Infection with the sigE mutant led to the formation of granulomas with distinct characteristics compared to those induced by the wild-type strain.
• The sigE mutation impacts Mtb's ability to establish infection and modulate the host immune response.

Conclusions:

• The sigE gene is important for the full virulence of Mycobacterium tuberculosis H37Rv in a mouse model.
• Attenuation of the sigE mutant suggests its role in Mtb pathogenesis and survival within the host.
• The altered granuloma formation indicates sigE's influence on host-pathogen interactions during tuberculosis infection.