Light microscopy resolution barrier-broken!!!
I was checking out the news items at Science Daily today, and came across this news brief: at the recent annual meeting of the American Biophysical Society, held in Baltimore last week, a report was presented examining the surface of Yersinia pestis, the etiologic agent of Bubonic Plague. Researchers at Sandia National Laboratory in New Mexico, used the technique of Stochastic Optical Reconstruction Microscopy (STORM) to examine molecules on the surface of human neutrophils encountering either E. coli cells or Y. pestis cells. As we have learned in the chapter on Innate Immunity, this interaction is mediated by “patterns” found on the surface of the pathogen, and pattern recognition proteins on the surface of the immune cells. Specifically in these partners, Toll-like receptors found on the immune cells and lipopolysaccharide (LPS) on the bacterial cells interact with one another leading to the establishment of the immune response.
The scientists at Sandia National Laboratory have used the STORM technique, which utilizes a light-based microscope in combination with very precise wavelengths of light, beam splitters, color filters, and computer reconstruction to make an image with a resolution limit approximately ten times better than standard light microscopy. By using this technique, they have been able to see that when the immune cells and E. coli cells interact via the TLR4-LPS connection, the TLR proteins on the surface of the immune cell clump together, leading to the turning on of the immune response by the neutrophil. This clumping does not seem to occur with Y. pestis, meaning that the immune response doesn’t get initiated to the same degree with this organism. This may be one reason that Y. pestis is a much more virulent pathogen than E. coli; it is not as effectively cleared by the immune system when it initiates infection.
I don’t expect that we’ll be replacing all of our microscopes at YCP with STORM scopes anytime soon, as I imagine that the cost would mean a doubling of the yearly tuition costs.
BONUS: this report describes an immune interaction that is exploited by a specific microorganism to escape immune surveillance. In the comment thread, list other patterns that are recognized by the immune system to identify “foreign” objects.