Advanced imaging techniques provide new clues to HIV infection

Researchers from the University of Minnesota’s Institute of Technology and the National Institutes of Health’s National Cancer Institute are using advanced imaging techniques to visualize how a key part of the human immunodeficiency virus (HIV) changes shape after binding to infection-fighting antibodies.

Guillermo Sapiro, a University of Minnesota professor of electrical and computer engineering, is part of the team working to understand the structure of the HIV spike on virus particles. Although scientists had been able to visualize individual components of this part of the virus, the new research characterizes, for the first time, the structure of the intact spike on virus particles, which is a crucial piece to designing new vaccines or drugs to fight HIV infection. The results were published in the July 30 issue of Nature.

Using the imaging technique, cryo-election tomography, the team produced three-dimensional renderings of the spike by freezing the virus and taking images of it from various angles. They were then able to develop advanced computer image-processing methods to average thousand of high-resolution three-dimensional images of individual HIV spikes, which they could then interpret in terms of atomic structures. With this technique, the researchers were able to understand the structure and design of the HIV spike, which is at the heart of the HIV virus.

"These advances in electron tomography, both at the acquisition level and at the analysis and computational level, are part of an extraordinary interdisciplinary collaboration with Dr. Sriram Subramaniam, head of the National Cancer Institute's Biophysics Section, and National Cancer Institute staff scientist Alberto Bartesaghi, a 2005 University of Minnesota alumnus,” said Sapiro. “This research enables us to arrive at new understandings—at never seen before resolutions and detail—of viruses and other cells."