The prospect of a single drug to treat a range of viruses, including HIV, ebola, measles and flu, is a step closer.
New research suggests that many retroviruses need a protein called ubiquitin to be infectious. Ubiquitin enables a virus to 鈥榖ud鈥� from an infected cell. Once released it can travel to infect another.
In lab tests, chemicals that lowered ubiquitin levels reduced the spread of the HIV1 and HIV2 viruses between immune system cells by 98 per cent.
Advertisement
鈥楶roteasome-inhibiting鈥� drugs are currently in human trials as an anti-cancer treatment, but they could also be important for treating viral infections, says Ulrich Schubert of the National Institutes of Health in Bethesda, Maryland.
鈥淲e have also done tests with other viruses, which have been successful. But these results have not yet been published,鈥� he says.
鈥淲e do not understand the exact mechanism of how these drugs work to reduce viral infection,鈥� he warns. 鈥淎nd this is not yet a new treatment for HIV. But potentially, it could have very widespread applications.鈥�
Schubert鈥檚 research is published in the Proceedings of the National Academy of Sciences alongside two other papers investigating the role of ubiquitin in viral infection. A retrovirus spreads by wrapping its DNA in the membrane of a cell. It then leaves that cell and fuses with another.
鈥淭hese articles provide an important new clue to the mechanism by which retroviruses bud,鈥� says Volker Vogt of Cornell University in New York.
Ubiquitin is part of the body鈥檚 proteasome system, which destroys old or damaged proteins. A single ubiquitin molecule attached to a protein helps regulate its function. But multiple ubiquitin molecules target that protein for destruction.
Proteasome inhibitors prevent recycling of the ubiquitin molecules, reducing the number of freely available ubiquitin molecules.
Schubert suspects that a lack of ubiquitin means a key protein allowing a virus to bud does not form properly.
鈥淭he folding of this protein is a highly complicated process. We believe that blocking the proteasome system induces it to misfold,鈥� Schubert told 快猫短视频.
Some workers fear that reducing the activity of the proteasome system sufficiently to stop the spread of a virus may have significant side effects.
But Schubert says: 鈥淭he human trials with cancer patients suggest there are very few side effects. Obviously, you do not want to shut down all proteasome activity. But it seems that cells can tolerate quite a high number of proteasome inhibitors 鈥� they seem to adapt.鈥�
More at: Proceedings of the National Academy of Sciences (vol 97, p13057, p13063, p13069)