Eliminating Cells Produce Distress Signal When Infected With HIV
The strategy of eliminating cells that display a "distress signal" whenthey are infected with HIV might lead to the development of a new HIVvaccine candidate, according to a study published Thursday in the journal PLoS Pathogens, the San Francisco Chronicle reports.
About8% of DNA in the human genome consists of viral genes inserted millionsof years ago, and these ancient genes are activated when a cell isattacked by a modern virus, the Chronicle reports. The viruses produce tiny proteins that move to the surface of the cell after HIV infection and display a distinctive signal.
Accordingto the study, the signals -- called Human Endogenous Retroviruses --were found in 15 of the study's 16 participants who were HIV-positiveand had not yet taken antiretroviral drugs. Four HIV-negativeparticipants showed little to no evidence of the signals, according tothe study. The HIV-positive participants who had the lowest viral loadswere those who had the highest level of the signals, which indicatedthat their immune systems might be exercising some control over HIV,the Chronicle reports.
According to the Douglas Nixon, a University of California-San Franciscoimmunologist, and colleagues, the signals from these ancient virusesconsistently are found on cells infected with HIV, which are where thepotential of a vaccine that attacks HERVs might be successful. Ifscientists could develop a vaccine that stimulates a strong responseagainst these ancient viral signals, they might be able to eliminatethe HIV-infected cells, according to the Chronicle.
Nixonsaid that the research team is looking at a small subset of people whoare able to control HIV naturally -- called the "elite controllers" --who produce high levels of HERV proteins. UCSF research fellow KeithGarrison, who is the lead author of the study, also noted that thedistress signals might not be limited to infections with viruses suchas HIV -- and hence vaccines might be designed to prevent or treatother diseases
Nixon said that any vaccine developed to attackan ancient virus has the potential to attack friendly cells, which canprovoke a harmful autoimmune response. He added that much more researchis needed before a potential vaccine of this nature would be availablefor testing in humans (Russell, San Francisco Chronicle, 11/9).
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