Natural HIV immunity
Published: Wednesday, 16-Aug-2006
An international, multi-institutional research consortium is seeking to discover how a few HIV-infected individuals are naturally able to suppress replication of the virus.
The Elite Controller Collaborative Study, the first large-scale haplotype-mapping study in people infected with HIV, is searching for genetic factors that may explain these individuals' unique ability to control the virus without treatment, sometimes as long as 25 years after infection.
"If we could discover how these individuals can coexist with this virus without damage to their immune system and could find a way to replicate that ability in others, we would have a recipe for halting the HIV epidemic," says Bruce Walker, MD, director of Partners AIDS Research Center (PARC) at Massachusetts General Hospital and an initial organizer of the Elite Controller Collaborative Study. Walker discussed the project in a media briefing today at the 16th International AIDS Conference in Toronto.
Most people infected with HIV cannot control replication of the virus with their immune systems alone. Unless antiviral medications are used, the virus continues to reproduce until it overwhelms the CD4 T helper cells, suppressing the immune response and leading to AIDS. In the early 1990s, it was recognized that a small minority of HIV-positive people remained healthy and did not progress to AIDS despite many years of infection. The term "long-term nonprogressors" was used to refer to this group. With today's more sensitive techniques for measuring viral levels in the bloodstream, individuals who are able to maintain low levels of HIV replication can be identified soon after their infection is diagnosed. Some of these viremic controllers can maintain viral loads below 2,000 copies/ml, while an even smaller group, called elite controllers, have viral loads too low to be detected by currently available assays.
"The primary goal of the Elite Controller Collaborative Study is to identify the mechanism that explains control of viral replication in both of these groups, " says Florencia Pereyra, MD, of PARC, lead coordinator of the research team. "We want to use that knowledge to develop a first-generation HIV vaccine, which may not cure or prevent infection but could successfully suppress viral levels. Since this natural ability is so rare, we need to work with collaborators around the world to recruit the number of participants we will need to determine what is going on.
"We expect to need data from at least 1,000 such individuals in order to define the genetic factors associated with this extraordinary outcome," she adds. "This effort will only be possible with the collaboration of HIV researchers, providers, advocacy groups and most important the HIV-infected individuals that fall in this category."
Those eligible to participate in the Elite Controller Collaborative Study are HIV-positive adults, aged 18 to 75, who have maintained viral loads below 2,000 copies without taking HIV antiviral medications. Participation involves having a single blood sample taken, which can be done by participants' local healthcare providers. Those located near a participating research center may choose to be followed over time and provide additional blood samples.
"So far we have enrolled nearly 200 participants from 25 U.S. states, and we are looking forward to adding participants from other countries," says Pereyra. Potential participants or collaborating providers seeking more information should contact Rachel Rosenberg, Partners AIDS Research Center, (617) 726-5536 or firstname.lastname@example.org.
In addition to Walker, other organizers of the Elite Controller Collaborative Study are Eric Lander, PhD, director of the Broad Institute of Harvard University and Massachusetts Institute of Technology; Dennis Burton, PhD, of the Scripps Institute; Steven Deeks, MD, University of California at San Francisco; and Mary Carrington, PhD, of the U.S. National Cancer Institute. The current list of consortium members is on the next page. The project is supported by a philanthropic gift from the Mark and Lisa Schwartz Foundation.
艾滋病精英控制者协作研究（The Elite Controller Collaborative Study），第一个针对HIV感染人群的大规模单体型基因定位研究，正在寻找遗传因素来解释这些个体在感染病毒后不用治疗的情况下有时长达25年控制病毒的独特的能力。
“如果我们能揭示这些个体如何能够与病毒共存而不损害他们的免疫系统并且能够找到一种方法将这种能力复制给其他人，我们将能够阻止HIV的流行”，医学博士Bruce Walker说。Bruce Walker是马萨诸塞州总医院配偶艾滋病研究中心（Partners AIDS Research Center, PARC）的主管，也是The Elite Controller Collaborative Study的最初组织者之一。Walker今天在在多伦多举行的第16届国际艾滋病会议的媒体简报中讨论了这个研究项目。
作者:admin@医学,生命科学 2011-09-19 05:14