The viral reservoir, whose existence thwarts attempts to cure HIV infection with standard antiretrovirals, may be as much as 60 times larger than scientists have initially estimated, posing a setback for research progress, The Wall Street Journal reports. The latent reservoir is made up of what are called proviruses, in which viral DNA is inserted into immune cells' genomes. When researchers attempt to activate these cells in test tube cure research, during a process known as “shock and kill,” less than 1 percent of them wake from their latent state.

Publishing their findings in Cell Press, investigators sought to characterize the proviruses that remain in a resting state during this activation process. They discovered that a great number of them possess intact genomes and are able to replicate normally, contrasting the previous perception that they are defective. The study also found that the volume of these non-activated proviruses may increase the overall size of the latent reservoir to as much as 60 times its previously considered size.

“These results indicate an increased barrier to cure, as all intact noninduced proviruses need to be eradicated,” senior study author Robert Siliciano, MD, PhD, of Johns Hopkins University School of Medicine, said in a release. “Although cure of HIV infection may be achievable in special situations, the elimination of the latent reservoir is a major problem, and it is unclear how long it will take to find a way to do this.”

For a POZ feature on cure research, click here.

To read a release on the study, click here.

To read the Wall Street Journal story, click here.