Eliminating Cells That Produce A Distress Signal When Infected With HIV Could Lead To Strategy For New Vaccine Candidate, Researchers Say

Main Category: HIV / AIDS
Also Included In: Biology / Biochemistry;  Immune System / Vaccines
Article Date: 12 Nov 2007 - 9:00 PDT

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The strategy of eliminating cells that display a "distress signal" when they are infected with HIV might lead to the development of a new HIV vaccine candidate, according to a study published Thursday in the journal PLoS Pathogens, the San Francisco Chronicle reports.

About 8% of DNA in the human genome consists of viral genes inserted millions of years ago, and these ancient genes are activated when a cell is attacked 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.

According to the study, the signals -- called Human Endogenous Retroviruses -- were found in 15 of the study's 16 participants who were HIV-positive and had not yet taken antiretroviral drugs. Four HIV-negative participants showed little to no evidence of the signals, according to the study. The HIV-positive participants who had the lowest viral loads were those who had the highest level of the signals, which indicated that their immune systems might be exercising some control over HIV, the Chronicle reports.

According to the Douglas Nixon, a University of California-San Francisco immunologist, and colleagues, the signals from these ancient viruses consistently are found on cells infected with HIV, which are where the potential of a vaccine that attacks HERVs might be successful. If scientists could develop a vaccine that stimulates a strong response against these ancient viral signals, they might be able to eliminate the HIV-infected cells, according to the Chronicle.

Nixon said that the research team is looking at a small subset of people who are able to control HIV naturally -- called the "elite controllers" -- who produce high levels of HERV proteins. UCSF research fellow Keith Garrison, who is the lead author of the study, also noted that the distress signals might not be limited to infections with viruses such as HIV -- and hence vaccines might be designed to prevent or treat other diseases

Nixon said that any vaccine developed to attack an ancient virus has the potential to attack friendly cells, which can provoke a harmful autoimmune response. He added that much more research is needed before a potential vaccine of this nature would be available for testing in humans (Russell, San Francisco Chronicle, 11/9).

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