So far, HIV has eluded a cure because it installs its genome into human DNA so insidiously that it's impossible for our immune system to clear it out. While current treatments are effective, a lifetime of toxic drugs is required to prevent its recurrence. But researchers from Temple University may have figured out a way to permanently excise it using a highly-engineered HIV "editor." Here's how it works: the team analyzed a part of our immune system that fights infection and built a "guide RNA" strand consisting of 20 nucleotides (RNA building blocks). Those strands were then injected into cells typically infected with HIV, like T-cells. There, they targeted the end parts of the virus's gene and snipped out all 9,709 nucleotides that made up its genome. Since the guide RNA strand contained no human DNA sequences, it left the host cell intact -- but free from HIV.