Scientists develop experimental vaccine to prevent HIV

Scientists have developed a novel vaccine candidate that may prevent HIV infection by stimulating an immune response against sugars that form a protective shield around the virus.

"An obstacle to creating an effective HIV vaccine is the difficulty of getting the immune system to generate antibodies against the sugar shield of multiple HIV strains," said Lai-Xi Wang, a professor at University of Maryland in the US.

"Our method addresses this problem by designing a vaccine component that mimics a protein-sugar part of this shield," said Wang.

Researchers designed a vaccine candidate using an HIV protein fragment linked to a sugar group. When injected into rabbits, the vaccine candidate stimulated antibody responses against the sugar shield in four different HIV strains.

The protein fragment of the vaccine candidate comes from gp120, a protein that covers HIV like a protective envelope.

A sugar shield covers the gp120 envelope, bolstering HIV's defenses. The rare HIV-infected individuals who can keep the virus at bay without medication typically have antibodies that attack gp120.

Researchers have tried to create an HIV vaccine targeting gp120, but had little success as the sugar shield on HIV resembles sugars found in the human body and therefore does not stimulate a strong immune response.
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NASA's Hubble Space Telescope captures tiny Martian moon Phobos

NASA's Hubble Space Telescope has beamed back images of the tiny Martian moon Phobos in its orbital trek around the red planet.

Over the course of 22 minutes, Hubble took 13 separate images, allowing astronomers to create a time-lapse video showing the diminutive moon's orbital path.

The Hubble observations were intended to photograph Mars, and the moon's cameo appearance was a bonus, scientists said.

A football-shaped object just 26x21x17 kilometres, Phobos is one of the smallest moons in the solar system.

The moon completes an orbit in just seven hours and 39 minutes, which is faster than Mars rotates.

Rising in the Martian west, it runs three laps around the Red Planet in the course of one Martian day, which is about 24 hours and 40 minutes.

It is the only natural satellite in the solar system that circles its planet in a time shorter than the parent planet's day.

About two weeks after the Apollo 11 manned lunar landing on July 20, 1969, NASA's Mariner 7 flew by the Red Planet and took the first crude close-up snapshot of Phobos.
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