How our body fights infection

January 6th, 2009 - 12:18 pm ICT by ANI  

Washington, Jan 6 (ANI): It is a well-known fact that our immune system adapts itself to every new microbe it encounters. Now, scientists from Wayne State University in Detroit have shed light on how humans antibody-forming system makes “evolutionary leap” to stave off infection.

The study shows that a ”cluster mutations” help our antibody formation system adapt to infection.

The process involves altering the genes that code for antibodies to specific viruses or bacteria.

“We”ve known for a long time that our antibody-forming system adapts itself to every microbe we encounter but what we didn”t understand fully is exactly how this happens, said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal.

Now that we know, we can begin to find ways to manipulate this process so illnesses can be prevented or made significantly less dangerous,” he added.

When the body encounters a foreign invader, like a virus or bacterium, it immediately begins to find a way to neutralize it by means of cellular or antibody-mediated defences.

The process involves two types of genetic manipulation. One type changes a single gene at a time, and the other type changes multiple genes at the same time.

Scientists have explained how multiple genes can be modified simultaneously to make the “evolutionary leap” necessary to stave off infection.

During the study, the researchers treated DNA responsible for making antibody molecules with an enzyme, called activation-induced deaminase, while the DNA was being copied by RNA polymerase.

Like a scanner, RNA polymerase moves across the DNA to copy it. When this scanning process moved smoothly, there were either single mutations or no mutations.

When the researchers made the RNA polymerase stall along the DNA (under certain conditions), it caused several mutations at once (cluster mutations) in the DNA, adapting our antibodies for a rapid and effective response to a new microbial invader.

“As the planet warms, infectious diseases may be one the biggest threats to human survival,” Weissmann said.

“Nowadays, mosquitoes, parasites and viruses cause diseases in the United States that were once isolated to warmer parts of the world.

They evolve, and - a la Darwin - so does our immune system each time we meet a new microbial invader,” he added.

The study appears in the FASEB Journal (ANI)

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