Decoding how cell memory helps immune system fend off invasions

January 25th, 2009 - 5:23 pm ICT by IANS  

Washington, Jan 25 (IANS) Resarchers are close to decoding the mystery of how immune cells fend off infections by remembering and recognising the nature of invading pathogens.Their key finding is that a distinct programme generates memory cells to protect an individual against re-infection. This current work unravels some of the language that kickstarts this programme, said Teixeiro, assistant professor of molecular microbiology, immunology and surgery, University of Missouri School of Medicine (UMSM), US.

Teixeiro cites vaccination as the most practical and conspicuous example of how to generate cells that remember infections. A single shot infects the body with a tiny dose of a pathogen, so the next time the body is exposed, it immediately recognises the invader and fights it off, preventing disease.

“When the human body is infected, T-cells recognise the pathogen with a specific receptor and kill the infection,” Teixeiro said. “But once the infection has been cleared, a small number of cells survive. These are the memory T-cells.”

Teixeiro’s lab used a mouse model to test how communication inside a T-cell would affect a body’s ability to fight infection.

Two groups of mice - some with normal T-cells and others with a mutation in their pathogen receptor - were infected with listeria monocytogenes, a bacterium often associated with food-borne illness in humans.

Both groups of mice fought off the infection equally well, but those with the cell mutation were not able to generate memory T-cells to protect against future infection due to a disruption in certain signals within the cell, said a UMSM release.

“A person with this cell mutation would not develop memory T-cells. If we knew what was necessary to generate these memory cells, we would not need to worry about fighting the same infection over and over again,” Teixeiro said.

“We are currently figuring out which signals are important for memory generation and protection. This is important for improving vaccines and tumour immunotherapies,” he added.

These findings were published in the Friday issue of Science.

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