Most bacterial infections can be treated with antibiotics such as penicillin, but these drugs are useless against viral infections, including influenza, the common cold, and deadly hemorrhagic fevers such as Ebola.
Now a team of researchers at MIT’s Lincoln Laboratory has designed a drug that can identify cells infected by any type of virus, then kill those cells to terminate the infection.
In tests in human and animal cells, the researchers found their drug effective against 15 viruses, including H1N1 influenza, rhinoviruses that cause the common cold, a stomach virus, a polio virus, dengue fever, and several other types of hemorrhagic fever. The researchers also showed that mice infected with H1N1 and treated with the new drug were completely cured.
The drug works by targeting a type of RNA produced only in cells that have been infected by viruses. “In theory, it should work against virtually all viruses,” says Todd Rider, a senior staff scientist in Lincoln Laboratory’s Chemical, Biological, and Nanoscale Technologies Group, who invented the new technology.
Rider drew inspiration for his therapeutic agents, dubbed DRACOs (double-stranded RNA-activated caspase oligomerizers), from living cells’ own defense systems.
When viruses infect a cell, they take over its cellular machinery to create more copies of themselves. During this replication process, the viruses create strings of double-stranded RNA (dsRNA), which is not found in human or other animal cells. Human cells have proteins that latch onto dsRNA, setting off a cascade of reactions that prevents the virus from replicating itself. However, many viruses can outsmart that system by blocking one of the steps further down the cascade.
Rider had the idea of combining a dsRNA-binding protein with a protein that induces cells to undergo apoptosis, a form of programmed death normally launched, for example, when a cell determines that it’s en route to becoming cancerous. When one end of the DRACO binds to dsRNA, it signals the other end of the DRACO to initiate cell suicide.
The researchers are now testing DRACO against more viruses in mice and are beginning to get promising results. Rider says the next step is to run trials in larger animals in preparation for eventual human clinical trials.