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The good old days
Ancient Bacterial DNA Could Thwart a Devastating DiseaseThe unique bacterial DNA of CpG oligonucleotides will reinforce the hepatitis B vaccine and could drop liver cancer rates.Paul Offit
11.24.17 12:00 AM ET
Hepatitis B virus infects around 20,000 people per year in the United States, according to the CDC. Typically, the virus causes severe inflammation of the liver. Symptoms include fatigue, muscle aches, jaundice, abdominal pain, fever, discolored urine, weight loss, and an inability to tolerate fatty foods.
Normally, the virus comes and goes—but sometimes the virus causes long-term liver damage (cirrhosis) or liver cancer. In fact, hepatitis B virus is the most common cause of liver cancer in the world.
Two hepatitis B virus vaccines are currently on the market. Earlier this month, however, the Food and Drug Administration licensed another hepatitis B vaccine. This new vaccine employs a unique strategy: fighting the hepatitis B virus with … bacterial DNA.
Here’s how it works. All of our cells contain DNA, consisting of various combinations of nucleotides called cytosine, guanine, adenine, and thymine. DNA provides a blueprint that instructs cells on how to reproduce themselves.
Bacteria also contain DNA. Bacterial DNA, however, has certain patterns of nucleotides that aren’t found in human DNA. From the moment that we crawled out of the ocean onto land, we have been able to recognize these unique bacterial DNA patterns—a crude and early part of our immune system. There’s a reason for this primitive form of immunity: Once microbes breach the surface of our skin or intestines, where they live in large numbers, they can kill us. We need a defense system that is capable of recognizing these unique bacterial-specific molecular patterns and responding to them—immediately.
Which brings us back to the new hepatitis B vaccine. It’s identical to the two existing hepatitis B vaccines—which have been available since the 1990s—in that it contains 20 micrograms of a protein that is located on the surface of the virus. But unlike these other hepatitis B vaccines, the new vaccine also contains 3 milligrams of repeated linkages of cytosine and guanine—a molecular pattern unique to bacterial DNA called CpG oligonucleotides.
It’s the first time this immune-boosting product has been used in a vaccine. (The “p” just stands for the phosphodiester linkage that binds the cytosine and guanine.)
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发表于 2017-11-25 10:59
