Mycobacterium bovis Requires P27 (LprG) To Arrest Phagosome Maturation and Replicate within Bovine Macrophages

Area of Science:

• Microbiology
• Immunology
• Cell Biology

Background:

• Mycobacterium bovis causes tuberculosis in mammals, including cattle and humans.
• The P27 protein (LprG) is implicated in the virulence and persistence of M. bovis and M. tuberculosis.

Purpose of the Study:

• To investigate the novel function of P27 in the interaction between M. bovis and bovine macrophages.
• To elucidate the role of P27 in the early stages of M. bovis infection.

Main Methods:

• Genetic manipulation of M. bovis to create a deletion in the p27-p55 operon.
• Infection of bovine macrophages with wild-type and mutant M. bovis strains.
• Analysis of phagosome maturation and phagosome-lysosome fusion.

Main Results:

• A deletion in the p27-p55 operon impaired M. bovis replication in bovine macrophages.
• M. bovis arrests phagosome maturation in a P27-dependent manner.
• P27, but not P55, was responsible for blocking phagosome maturation, indicating P55's limited role in early infection events.
• P27 modulates host cell machinery to inhibit phagosome-lysosome fusion.

Conclusions:

• P27 is crucial for M. bovis to evade host immune responses by preventing phagosome maturation.
• P27's ability to block phagosome-lysosome fusion is a key virulence factor for M. bovis persistence in bovine macrophages.
• Targeting P27 could be a potential strategy to combat M. bovis infections.