AsianScientist (Dec. 3, 2013) – A new study published in Nature Immunology shows how golden staph (Staphylococcus aureus) identifies key immune cells and ‘nukes’ our body’s immune response when it enters our skin.
The international research group, led by dermatologists from the Centenary Institute and the University of Sydney, included researchers from Monash University, the Agency for Science, Technology and Research in Singapore and Harvard Medical School in the US.
Using state-of-the art microscopy techniques, the team identified the key immune cells that orchestrate the body’s defenders against invading golden staph, and also how the bacteria can target and destroy these cells, circumventing the body’s immune response.
“Staphylococcus aureus kills many, many people around the world. In fact, more than tuberculosis and AIDS put together. And the skin is its primary entry point into the body, so it important to understand what happens in the skin,” said Professor Wolfgang Weninger, head of the Immune Imaging Research Program at Centenary and coordinator of the study.
Using techniques developed over the past decade, the research team was able to mark different cells of the immune system with fluorescent tags of different colors. They then observed the unfolding battle live under a multiphoton microscope using bacteria engineered with similar colored tags.
The initial shock troops of the body’s defense against the invading bacteria, immune cells known as neutrophils, were observed moving out from the blood vessels to fight against the bacteria. About 80 percent emerged at points close to where large immune cells called macrophages were sitting. The macrophages release proteins that activate the neutrophils and guide them out of the blood vessels.
“But we also found that as soon as the bacteria enter the body, they release a compound called alpha-haemolysin which directly destroys the macrophages, thus disrupting the system that is marshaling the defense forces against them,” said Weninger.
The release of alpha-haemolysin gives the golden staph time to multiply and overwhelm the immune system. By the time reinforcements arrive, the tissue surrounding the site of infection has begun to die, diverting the immune system into the task of cleaning up the debris.
The article can be found at: Abtin A et al. (2013) Perivascular macrophages mediate neutrophil recruitment during bacterial skin infection.
——
Source: The University of Sydney; Photo: NIAID/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
