Diverse infection models demonstrate robust resistance of Mycobacterium tuberculosis to innate immunity.

Mycobacterium tuberculosis shows strong resistance to innate immune clearance across multiple infection models, even with pre-activation of innate immunity.

• Why it matters: Understanding the capacity of innate immunity to control Mtb is crucial for developing effective interventions, as prior models may have underestimated innate immune responses due to high infectious doses and specific conditions.
• What they did: The study used ultra-low dose infections, co-housing with pet shop mice, and pre-infection with Legionella pneumophila in mice, combined with single-cell RNA sequencing of myeloid cells, to assess innate immune control of Mtb.
• The result: Results show that innate immunity alone cannot significantly reduce Mtb infection levels, even when primed or activated, highlighting Mtb’s robust resistance to innate immune mechanisms.