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5 December 2013 11:26 am ,
Vol. 342 ,
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
A Natural Vaccine?
19 November 1997 8:00 pm
One of the hottest trends in immunology--injecting DNA as a vaccine--may actually have been invented millions of years ago. In tomorrow's Nature, a team led by immunologist Rolf Zinkernagel from the University Hospital in Zurich, Switzerland, suggests that animals may gain lifelong immunity to some viral infections by retaining a bit of viral DNA inside their cells like a souvenir.
After the body has defeated a viral or bacterial invasion, the immune system usually starts losing its memory of the attacker as the last invaders fade away. Yet, after mice have beaten an infection with the lymphocytic choriomeningitis virus (LCMV), they remain immune--even long after the virus has vanished from their bodies. The Swiss team decided to check the mouse spleen cells for a possible long-term remnant of the infection: viral-looking DNA. To look for DNA was perhaps, as Zinkernagel puts it, "a crazy idea," because LCMV doesn't produce DNA at all; like many other viruses, it uses the slightly different RNA to perpetuate its genetic information.
To their surprise, the team did find DNA "copies" of viral RNA in mouse cells until at least 225 days after infection. The copies were made from RNA by the enzyme reverse transcriptase (RT), since an RT inhibitor blocked viral DNA production in infected cells. Perhaps, the Swiss team suggests, the animals use RT to make the viral DNA, in order to keep their immune systems alert after the virus is gone. This idea was bolstered by the finding that viral DNA production also took place in cells from another natural LCMV host, the hamster, but not in human, monkey, dog, or cow cells, which are not susceptible to the virus.
The finding is "very original and a lot of fun," says Jaap Goudsmit, a virologist at the Academic Medical Center in Amsterdam. However, he notes that Zinkernagel hasn't yet proven that the DNA is the cause of the mice's immunity. To do that, the team would have to show that DNA is actually translated into a protein, which in turn has to trigger an immune response. But even without that evidence, Goudsmit says, "It's a lovely experiment."