Bacteria "talk" to fight virus infections: New Zealand study

A New Zealand study has found that bacteria can boost their immune systems by "talking" to each other, providing a new insight into how they survive infections.

Research by microbiologists provided new insight into how groups of bacteria collectively defend against viral threats.

"As humans, we have evolved sophisticated immune systems that enable our bodies to fight the viral infections that render us ill," Associate Professor Peter Fineran said in a statement Tuesday.

"Amazingly, bacteria although single-celled organisms often possess similar adaptive immunity called CRISPR-Cas systems. But the way that these CRISPR-Cas systems function is very much different to our own immune systems," he said.

Bacteria, like people, lived in communities, but living in close quarters made them more vulnerable to the spread of viruses.

The researchers discovered that the ability of bacteria to gauge the number of cells in their communities enabled them to boost the power of their CRISPR-Cas immune systems to prevent viral outbreaks.

The bacteria sense the population density by "talking" to each other using a form of chemical communication known as quorum sensing.

"The higher the population density, the stronger the communication between cells becomes, which results in greater coordination of immune defenses," said Fineran.

Researcher Adrian Patterson said the study showed that bacterial cells preemptively elevated their immunity when they were most at risk of a virus spreading through the population.

"They both increase their ability to generate new immune memories and strengthen existing immunity by up to 500-fold," Patterson said in the statement.

The role of CRISPR-Cas in providing bacteria with viral immunity was only discovered in the past decade.

The systems created genetic memories of specific past viral infections by taking snippets of the viruses' DNA and storing them in memory banks to aid in recognizing and destroying future infections.

One of the least understood aspects of the CRISPR-Cas field was how bacteria controlled the activity of these systems too much activity could result in an autoimmune-like disease, killing the host cell, but too little activity might allow viruses to wipe out entire bacterial communities.

The research showed that by openly communicating with each other, bacteria strike the right balance between these two outcomes. Endit