AIDS: long research road still looms ahead.AIDS: Long research road still looms ahead
Three basic research reports provide useful insights into the AIDS-causing virus (HIV HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. ), but the news that emerges is not all heartening heart·en
tr.v. heart·ened, heart·en·ing, heart·ens
To give strength, courage, or hope to; encourage. See Synonyms at encourage.
Adj. 1. . In particular, one study suggests that an experimental drug called soluble CD4 appears less promising than once thought. Taken together, the three studies -- detailed in the Dec. 14 SCIENCE -- serve as a reminder that despite remarkable gains made by AIDS researchers in the past few years, the deadly virus they seek to understand remains insidiously difficult to manage.
In an encouraging report, molecular biologists describe isolating a piece of HIV's genetic code they hope to use in an AIDS vaccine AIDS vaccine A hypothetical vaccine intended to either prevent HIV infection or ensure that those infected will not fall victim to AIDS; the most promising vaccine is that using a naked DNA plasmid, reported by Letwin et al in 20/10/00 Science; as of early 2001, . Scientists have had difficulty developing a vaccine that protects against all HIV strains because vaccine-induced antibodies that attack some strains prove useless against others.
With seven others, Kashi Javaherian of Repligen Corp. in Cambridge, Mass., vaccinated guinea pigs with a six-amino-acid sequence found on the outer coats of about 60 percent of HIV strains. The animals made antibodies that "neutralized," or rendered noninfectious, widely divergent strains of HIV bearing the key sequence on their viral coats. In earlier efforts, the researchers vaccinated animals with larger proteins that included the six crucial amino acids. But the surrounding amino acids apparently diverted much of the animals' antibody-making machinery away from the six key targets, says study coauthor Dani P. Bolognesi of Duke University Medical School in Durham, NC.
The new work suggests that a vaccine containing the six-amino-acid sequence and other proteins common to other HIV strains might provide broad protection against HIV infection in humans, Bolognesi says. However, he adds, it remains unclear just what or how many ingredients such a vaccine would require.
In a separate report, Dana Giulian and his colleagues at the Baylor College of Medicine Baylor College of Medicine is a private medical school located in Houston, Texas, USA on the grounds of the Texas Medical Center. It has been consistently rated the top medical school in Texas and among the best in the United States. in Houston describe an in vitro in vitro /in vi·tro/ (in ve´tro) [L.] within a glass; observable in a test tube; in an artificial environment.
In an artificial environment outside a living organism. system that mimics the environment of an ADS-infected brain and may help scientists identify new treatments for AIDS-related neurologic damage. Researchers remain baffled by AIDS' central nervous system complications, which range from mild weakness to paralysis and dementia. HIV seems not to infect neurons directly. But the infection triggers an accumulation of white blood cells White blood cells
A group of several cell types that occur in the bloodstream and are essential for a properly functioning immune system.
Mentioned in: Abscess Incision & Drainage, Bone Marrow Transplantation, Complement Deficiencies in the brain, leading some to suggest that these cells, called macrophages Macrophages
White blood cells whose job is to destroy invading microorganisms. Listeria monocytogenes avoids being killed and can multiply within the macrophage. , may be inadvertent culprits.
The new in vitro system helps identify compounds secreted by HIV-infected white blood cells, and the tests the effects of those compounds on cultured neurons. Using the system, the Baylor team has identified a previously unrecognized neurotoxin neurotoxin /neu·ro·tox·in/ (noor´o-tok?sin) a substance that is poisonous or destructive to nerve tissue.
See neurolysin. secreted by HIV-infected macrophages. Moreover, Giulian says, their findings indicate that at least some AIDS-induced neuronal destruction occurs via one of the same biochemical mechnsms that cause brain damage during a stroke, suggesting that drugs useful for limiting the effects of stroke may someday play a role in minimizing the neurologic complication of AIDS.
In perhaps the most disappointing AIDS FINDING REPORTED THIS WEEK, researchers at the columbia University College of Physicians and Surgeons The Columbia University College of Physicians and Surgeons, abbreviated P&S, is a graduate school of Columbia University located on the health sciences campus in the Washington Heights neighborhood of Manhattan. in New York City New York City: see New York, city.
New York City
City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. Showed that some viruses undergo mutations that enable them to circumvent an otherwise promising anti-viral strategy. Researchers had hoped they could prevent HIV infection in humans by flooding the bloodstream with engineered receptor molecules, called soluble CD4, that mimic the docking sites through which HIV enters cells. But Vincent B. Racaniello and his co-workers find that polioviruses can mutate mu·tate
intr. & tr.v. mu·tat·ed, mu·tat·ing, mu·tates
To undergo or cause to undergo mutation.
[Latin m in ways that prevent them from binding to soluble receptors while leaving them perfectly capable of infecting living cells. It's unclear how polioviruses manage this trick, or whether HIV can do the same, but the researchers say the findings "temper enthusiasm for the use of soluble receptors as antiviral compounds."