TB bacteria blocks immune cell production

The tuberculosis bacteria has a unique molecule on its surface that blocks a key part of the body’s defense. Research suggests this is a novel mechanism in the microbe’s evolving efforts to remain hidden from the human immune system.

Researchers found the TB bacterium has a molecule on its outer surface called lipomannan that can stop production of an important protein in the body’s immune cells that helps contain TB infection and maintain it in a latent state.

This protein is called tumor necrosis factor (TNF). When TNF is not produced in sufficient quantities, the TB bacterium can grow unchecked and cause an uncontrolled active infection inside and outside of the lungs.

Lipomannan resembles a tree branch sprinkled with smaller sugar molecules protruding from the outer cell wall of the bacterium. The findings show that lipomannan can block TNF production at the microRNA level. MicroRNAs are small segments of RNA that regulate – or fine-tune – a gene’s protein-building function.

Read more at Proceedings of the National Academy of Sciences