Researchers Hoping That "Elite Controller" Could Help in HIV/AIDS Vaccine Development
August 14, 2008
An HIV-positive woman who has never shown symptoms of the virus might provide insights into HIV/AIDS vaccine development, researchers from Johns Hopkins University said in a study recently published in the Journal of Virology, Reuters reports.
The researchers said the study disproved some theories about elite suppression, including those that claimed such suppression always involved a defective or weakened HIV strain, which is easier for the immune system to attack, or that genetic variants confer a protective effect in suppressors. According to Blankson, "This an extremely rare case of coinfection in a controlled, monogamous relationship, which showed us how a strong immune system in the elite suppressor kept the virus from replicating and infecting other cells." Blankson added, "Our findings offer hope to vaccine researchers because they reveal that the immune system's primary offense, known as CD8 killer T-cells, can effectively halt disease progression by a pathogenic form of HIV" (IANS/Yahoo! News, 8/12).
Tests conducted by the researchers indicate that the woman's CD8 cells stalled HIV replication by as much as 90%, while the man's cells stalled replication by 30%. In an apparent response to this attack by her immune system, the woman's HIV also has mutated to become weaker, while the man's HIV has remained strong, Reuters reports.
According to Blankson, the researchers are trying to figure out how the woman's T-cells work to inhibit viral replication. According to Reuters, the researchers determined that while the man's T-cells make only one kind of cytokines -- which are immune system signaling proteins -- called gamma interferon, the woman's made that one and another called tumor necrosis factor. However, the cytokines cannot explain the woman's ability to suppress HIV, Reuters reports, because HIV/AIDS researchers have tried using such immune system proteins in patients and found they did not work well. Furthermore, the woman's immune cells seem to respond in this manner only when they encounter the virus. Blankson said the case could be explained by the possibility of the woman having unusual activity in her human leukocyte antigen system, which helps recognize bacterial and viral antigens (Reuters, 8/12).
The study is available online.
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This article was provided by Henry J. Kaiser Family Foundation. It is a part of the publication Kaiser Daily HIV/AIDS Report. Visit the Kaiser Family Foundation's website to find out more about their activities, publications and services.