Developments to Watch
One More Step toward an AIDS Vaccine
A STANDARD APPROACH TO MAKING A VACCINE is to select a key substance from the outside of a virus or bacterium, then use it to prod an uninfected body into making antibodies that can neutralize any invading strain of the bug. But when scientists tried this approach on HIV, early in the AIDS epidemic, it failed. They synthesized parts of HIV's envelope glycoproteins, called gp120, which did indeed stimulate antibodies. But these were no match for the AIDS virus. A key reason, researchers learned, is that gp120 changes shape as the virus fuses with the cells it infects--and the antibodies are unable to block it.
But what if antibodies could be generated against gp120's new shape? A team of scientists at the University of Montana and New York University conducted an experiment, reported in the Jan. 15 issue of Science, in which they managed to capture the glycoprotein in the act of fusing with cell receptors and hold it in the new shape before injecting it into mice. "Perhaps to the surprise of all involved, this ambitious experiment worked," write AIDS experts David C. Montefiori and John P. Moore in an accompanying commentary. Confronted with a new protein shape that offers a more vulnerable attack site, the mice's immune systems made antibodies capable of neutralizing a wide variety of HIV strains.
Still, scientists caution that a truly effective vaccine may also have to stimulate the production of killer T-cells capable of killing HIV-infected cells, because the antibodies alone may not be enough.EDITED BY NEIL GROSSReturn to top
Heat and Light from the Far Side of the Moon
BILLIONS OF RESEARCH DOLLARS HAVE BEEN INVESTED IN FUSION ENERGY--the nuclear reaction that keeps stars burning. For these bets to pay off big, however, the world could use more helium-3, an isotope that seems to be the optimum fusion fuel. Helium-3 is extremely rare on earth, so researchers are looking at the moon.
Helium-3 has many advantages over the radioisotope tritium, which is now the main fuel candidate. Helium-3 would give off very little neutron radiation when fused with hydrogen, so it would take longer for helium-3 fusion plants to become hazardous. They would also cost less. Another advantage over tritium: Helium-3 wouldn't lead to by-products that are both toxic nightmares and vulnerable to theft by terrorists for use in weapons.
To secure a supply of helium-3, the U.S. Geological Survey has teamed up with space scientists at the universities of Arizona and Hawaii. Their computer simulations point to abundant helium-3 deposits on the moon, particularly on the far side--enough to last for centuries.
How did it get there? Researchers say the helium-3 blows in on the solar wind, the stream of particles emitted by the sun's own fusion reactions. Because the moon is not sheltered from the solar wind by an atmosphere, helium-3 has been accumulating there, atom by atom, for millennia. Of course, mining the moon cost-effectively may prove nearly as challenging as perfecting a safe, economic fusion reactor.EDITED BY NEIL GROSSReturn to top
Making Life Easier for Diabetics
WITHOUT CAREFUL MANAGEMENT, DIABETES CAN LEAD TO DIRE COMPLICATIONS, including stroke, blindness, and heart disease. It affects an estimated 120 million people worldwide whose bodies don't produce enough insulin to regulate their blood-glucose levels properly. Many diabetics check their glucose levels frequently by pricking a finger to draw a drop of blood for analysis with a home testing kit. But some patients find this procedure uncomfortable and fail to test themselves regularly.
NEC Corp. wants to make life easier for diabetics. It has developed a new urine test that it claims can give accurate results at home in just 10 seconds. The tester is a pen-shaped device that contains a tiny glucose sensor covered by a semipermeable film. The film is highly selective: Glucose in the urine can penetrate it and bind to the sensor, but compounds that obscure glucose measurements, such as vitamin C, cannot. Researchers at NEC's Central Research Laboratories spent five years developing the device. It could be on the Japanese market later this year, pending approval by Japanese health authorities.EDITED BY NEIL GROSSReturn to top