M. tuberculosis blocks apoptosis and ag presentation to maintain virulence

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varsha
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M. tuberculosis blocks apoptosis and ag presentation to maintain virulence

M. tuberculosis infects alveolar macrophages. It prevents lysosomal fusion and acidification of the phagosome while also causing necrotic death.
In a study pblished in Nature Immunology, infection with Attenuated strain of MTb H37Ra (H37Rv being the virulent strain) causes apoptosis of infected macrophages and the infection is contained. H37Rv on the other hand blocks apoptosis, by causing proteolysis of annexin A and inhibiting annexixn dependent envelope formation. These cells die by cell lysis and dissemination of Mtb.
Nature Immunology

A Timmer
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That is really interesting.

That is really interesting. We see the opposite effect with Group A Streptococcus - it induces macrophage apoptosis and if that is blocked the macrophage can clear the bacteria more efficiently.

Pubmed link to JBC article