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New health benefits can come from mucus and viruses, researchers find.

by Cara Cooper
May 21, 2013


Phage cells, when combined with mucus, can provide extra immunity to viruses, researchers at San Diego State University found.

Viruses can cause a whole host of illnesses, but new research has found one that can actually help fight bacteria.
Researchers at San Diego State University have found that a virus, called “phage," can potentially provide a new, natural immune system when mixed with mucus cells in the body, helping it to protect naturally against bacteria.
“This has probably been happening on all mucosal surfaces and likely been happening for a really long time and we’re just now becoming aware of it,” Jeremy Barr said.  Barr is a post-doctoral research fellow at the Rohwer Laboratory at San Diego State. He led the study on phage and its effects on mucus-layered cells in the human body. 
Barr describes phage as “tiny little spacelanders,” and said that it is the most numerous biological entity on the planet.
Phage “has a head and tailfibers, and it will float around the environment and use its tail fibers to latch onto a bacterial cell,” Barr said. “It will latch on and inject DNA into bacterial cells then grow inside the bacteria and replicate and make more phage. Eventually it bursts out of the bacteria cell, kills the host and they’ll release tens of hundreds of more phage back into the environment.”
Barr said phage does not infect human or plant cells, only bacteria, making it harmless, but allowing for lots of potential benefits.  The amount of phage found in mucus and the surrounding environment is what started the idea for the study.
“We were seeing a lot more phage in mucosal surfaces in organisms, ranging from coral to fish to humans, but we didn’t know why or what it meant,” Barr said.
The group grew human lung cells in petri dishes to produce sterile mucus, and then applied phage to them. After washing off the phage, they added bacteria. They found that these cells were better protected from attacking bacteria than those without the added phage.
“Compared to cells that didn’t have the mucus layer, they showed no significant increase in the number of bacteria growing and also had higher amounts of cell deaths,” Barr said. “So you needed both the phage and the mucus to protect the cell death.”
Dr. Forest Rohwer, leader of the Rohwer Laboratory where the experiments were conducted, said that a better understanding of phage will allow for a better understanding of everything from human health.
“Probably 80 percent of genomic or genetic diversity is encoated by viruses, and in most cases we don’t know what it is,” Rohwer said.
Barr calls the research “platform technology” because he hopes it will spawn new fields of phage research.  He refers to the EColi outbreak from a couple years ago as something that could have potentially be avoided.
“We envision that you can maybe one day apply mucus sticky phage to put in people’s food or drinking water to coat people’s stomach or the mucus in their stomach and maybe make them a bit more resistant to these nasty bacterial infections,” Barr said.
Rohwer said that in the near future, scientists should be able to manipulate bacteria and phage and make it customizable for people.
“So say if you’re trying to change the relative number of bacteria species in your stomach, we have the system to say we need these kind of phage to hold on to the mucosal surface, and we want to make more phage of that type,” Rohwer said. “We can do that nowadays.”