A 3D AIDS Virus Photo taken at Florida State University displays the protein spikes on the virus’s surface that permit it to bind and merge with human immune cells.

Information from this AIDS research could advance the development of vaccines that will counter infection by targeting and disabling the sticky HIV-1 spike proteins. At least two research facilities already are crafting AIDS vaccine prospects based on early results uncovered by his group of structural biologists.

Never before rendered in such detail, the super-sized representations of the virus and its viral spikes have given researchers their first good look at the pathogen’s elaborate molecular surface structure that supports the infection process.

aids virus photoUntil now, despite exhaustive study by a number of science labs, the design features of the spikes and their allocation patterns on the surface of the virus membrane have been inadequately understood, which has limited recognition of how the virus infection really occurs and foiled efforts to create vaccines.

To produce the aids virus photos, research associates used a state-of-the art procedure called cryoelectron microscopy tomography. It produces three-dimensional images like those from a Computerized axial tomography scan, but at the plane of viruses and molecules instead of tissues and organs.

They imaged HIV specimens as well as a variant SIV (non-human primate) strain, genetically designed for the study by partners at the National Cancer Institute to exhibit about 74 spikes instead of the 14 found on the HIV virus – the additional spikes made it easier to work with. The virus specimens were suspended in a thin liquid film spread across the perforations of a small copper grid and then flash-frozen, producing a solid form of ice more comparable to clear glass than the normal crystalline form of ice cubes.

Once within the electron microscope, electrons pelted the samples from numerous angles, magnifying it more than 43,000 times to expose its surprising structure – removing the distortion caused by the typical imaging procedures involving drying and staining of samples.

As a result, the researchers were able to zero in on the envelope – the lipid membrane coating the virus itself. They photographed the spikes jutting from the envelope, which enclose the only viral protein molecules on the HIV exterior. The scientists also were able to catch super-sized photos of both the head of the spike and its bracing stalk. The spike head is charged with attaching the virus to the target cell. The stalk controls the fusion event in which HIV introduces its genes into the human host cells T lymphocytes and macrophages, for which the virus has a natural chemical attraction. Antibodies that actually bind to any of these spike parts will counteract the virus to prevent infection.

Researchers had imagined that the spike stalk consisted of a tight set of three rods held together with the head of the spike resting on top. But photos discovered that the stalk is divided into three legs, like a tripod, which multiplies their contact with the viral membrane. The tripod stalk indicates a new mechanism by which HIV-1 is so effectively able to fuse with cells. That crucial knowledge should facilitate the design of better weapons to combat the virus.

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