HIV Infection Stems From Few VirusesMay 16, 2008BIRMINGHAM, Ala. - A new study reveals the genetic identity of human immunodeficiency virus (HIV), the version responsible for sexual transmission, in unprecedented detail. The finding provides important clues in the ongoing search for an effective HIV/AIDS vaccine, said researchers at the University of Alabama at Birmingham (UAB). The UAB team found that among billions of HIV variants only a few lead to sexual transmission. Earlier studies have shown that a 'bottleneck' effect occurs where few versions of the virus lead to infection while many variants are present in the blood. The UAB study is the first to use genetic analysis and mathematical modeling to identify precisely those viruses responsible for HIV transmission. George M. Shaw, M.D., Ph.D., professor in the UAB departments of Medicine and Microbiology and senior author on the report, said the research sheds new light on potential vulnerabilities in the virus at a time when science, medicine and society are still reeling from the failure of a major HIV vaccine clinical trial. "We can now identify unambiguously those viruses that are responsible for sexual transmission of HIV-1. For the first time we can see clearly the face of the enemy," said Shaw, a project leader with the Center for HIV/AIDS Vaccine Immunology. The center is a National Institutes of Health-sponsored consortium of researchers at UAB, Harvard Medical School in Boston, Oxford University in England, the University of North Carolina in Chapel Hill and Duke University in Durham, N.C. The new HIV-1 findings are published online in the Proceedings of the National Academy of Sciences. The new study was performed by sequencing many copies of the HIV envelope gene present in the viruses taken from 102 recently infected patients. The envelope gene encodes for a protein called Env that forms part of the outer covering of the virus, and is responsible for its infectiousness. The researchers then used sophisticated mathematical models of HIV replication and genetic change to identify the virus or viruses responsible for transmission. In 80 percent of the newly infected patients, a single virus caused transmission, though each virus was different in each patient. In the other 20 percent of patients, two to five unique viruses caused transmission. "Previously, researchers employed inexact methodologies that prevented precise identification of the virus that initiated infection," said Brandon Keele, Ph.D., an instructor in UAB's Department of Medicine and lead study investigator. "Our findings allow us to identify not only the transmitted virus, but also viruses that evolve from it." The UAB team said their work would lead to new research on how different HIV genes and proteins work together to make a virus biologically fit for transmission and for growth in the face of mounting immunity. Statistics show that while the worldwide percentage of people infected with HIV has leveled off, the total number HIV cases is rising. In 2007, 33.2 million people were estimated to be living with HIV, 2.5 million people became newly infected and 2.1 million people died from AIDS, according to the Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organization. The new study was sponsored by grants from the National Institute of Allergy and Infectious Diseases and the Bill and Melinda Gates Foundation. It was conducted by researchers in the UAB departments of Medicine and Microbiology, at Duke University, Los Alamos National Laboratory and the Santa Fe Institute in New Mexico, the University of Massachusetts in Amherst, the University of North Carolina, Chapel Hill, the University of Maryland in College Park, the University of California, San Francisco, the University of Rochester in New York and the University of Cape Town in Rondebosch, South Africa. University of Alabama at Birmingham |
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| Related HIV Infection Current Events and HIV Infection News Articles Multiple health concerns surface as winter, vitamin D deficiences arrive A string of recent discoveries about the multiple health benefits of vitamin D has renewed interest in this multi-purpose nutrient, increased awareness of the huge numbers of people who are deficient in it, spurred research and even led to an appreciation of it as "nature's antibiotic." Many pregnant women avoid HIV screening in Africa 'Prevention is the best cure' is a common expression, but what happens if preventative measures are not used? A large proportion of pregnant Ugandan women are going out of their way not to be HIV tested, increasing the risk of mother-to-child transmission. An atomic-level look at an HIV accomplice Since the discovery in 2007 that a component of human semen called SEVI boosts infectivity of the virus that causes AIDS, researchers have been trying to learn more about SEVI and how it works, in hopes of thwarting its infection-promoting activity. Scientists explain binding action of 2 key HIV antibodies; could lead to new vaccine design A very close and detailed study of how the most robust antibodies work to block the HIV virus as it seeks entry into healthy cells has revealed a new direction for researchers hoping to design an effective vaccine. Global challenges and opportunities in fighting HIV/AIDS and neglected diseases Responding to the HIV/AIDS pandemic and tackling so-called neglected tropical diseases are the focus of the November/December 2009 edition of Health Affairs. HIV care providers applaud Congress' extension of Ryan White program Medical providers on the front lines of HIV care applaud the U.S. Congress for extending the Ryan White HIV/AIDS Program, helping to ensure that more than half a million low-income, uninsured, or underinsured people living with HIV/AIDS have access to lifesaving care. Pitt researchers find candidates for new HIV drugs While studying an HIV protein that plays an essential role in AIDS progression, researchers at the University of Pittsburgh School of Medicine have discovered compounds that show promise as novel treatments for the disease. NIH launches 2009 H1N1 influenza vaccine trials in HIV-infected pregnant women The first clinical trials to test whether the 2009 H1N1 influenza vaccine can safely elicit a protective immune response in pregnant women launched yesterday, and a trial to conduct the same test in HIV-infected children and youth will begin next week. Continuing racial differences in HIV prevalence in US HIV prevalence among African Americans is ten times greater than the prevalence among whites. This racial disparity in HIV prevalence has persisted in the face of both governmental and private actions, involving many billions of dollars, to combat HIV. HIV vaccine regimen demonstrates modest preventive effect in Thailand clinical study In an encouraging development, an investigational vaccine regimen has been shown to be well-tolerated and to have a modest effect in preventing HIV infection in a clinical trial involving more than 16,000 adult participants in Thailand. More HIV Infection Current Events and HIV Infection News Articles |
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