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This is an illustration of what happens when viral DNA enters the nucleus of a cell with low dUTP levels (left) versus high dUTP levels (right). A team of researchers based at Johns Hopkins has decoded a system that makes certain types of immune cells impervious to HIV infection. The system's two vital components are high levels of a molecule that becomes embedded in viral DNA like a code written in invisible ink, and an enzyme that, when it reads the code, switches from repairing the DNA to chopping it up into unusable pieces. The researchers, who report the find...

UC Irvine biologists have discovered that fats within cells store a class of proteins with potent antibacterial activity, revealing a previously unknown type of immune system response that targets and kills bacterial infections. Steven Gross, UCI professor of developmental & cell biology, and colleagues identified this novel intercellular role of histone proteins in fruit flies, and it could herald a new approach to fighting bacterial growth within cells. The study appears today in eLife, a new peer-reviewed, open-access journal supported by the Howard Hughes Medical Institute, the Max Planck Society and the Wellcome Trust. "We found that these histone proteins...

A team of researchers led by UC Davis Health System has found that human alpha-defensin 6 (HD6) – a key component of the body's innate defense system – binds to microbial surfaces and forms "nanonets" that surround, entangle and disable microbes, preventing bacteria from attaching to or invading intestinal cells. The research describes an entirely new mechanism of action for defensins, an important group of molecules known to bolster the defenses of circulating white blood cells, protect cellular borders from invasive pathogens and regulate which "friendly" microbes can colonize body surfaces. The discovery provides important clues to inflammatory bowel diseases,...

A new study published in the journal Respirology reveals that adult patients admitted to the hospital with pneumonia are more likely to die if they have Vitamin D deficiency. Vitamin D is known to be involved in the innate immune response to infection. The team of researchers at Waikato Hospital and the Universities of Waikato and Otago, measured vitamin D in the blood samples of 112 adult patients admitted with community acquired pneumonia during the winter at the only acute-care hospital in Hamilton, New Zealand. The researchers found that Vitamin D deficiency was associated with higher mortality within the first...

For years, a prevailing theory has been that one of the chief villains in Alzheimer’s disease has no real function other than as a waste product that the brain never properly disposed of. The material, a protein called beta amyloid, or A-beta, piles up into tough plaques that destroy signals between nerves. When that happens, people lose their memory, their personality changes and they stop recognizing friends and family. But now researchers at Harvard suggest that the protein has a real and unexpected function — it may be part of the brain’s normal defenses against invading bacteria and other microbes....

Sci. Signal., 16 February 2010 Vol. 3, Issue 109, p. pc4 [DOI: 10.1126/scisignal.3109pc4] PODCASTS Science Signaling Podcast: 16 February 2010 George Hajishengallis1, 2 and Annalisa M. VanHook3 1 University of Louisville School of Medicine, Department of Microbiology and Immunology, Louisville, KY 40292, USA.2 University of Louisville School of Dentistry, Oral Health and Systemic Disease, Louisville, KY 40292, USA.3 Associate Online Editor of Science Signaling, American Association for the Advancement of Science, 1200 New York Avenue, N.W., Washington, DC 20005, USA. Abstract: This is a conversation with George Hajishengallis about a Research Article published in the 16 February 2010 issue of...