Methicillin-resistant Staphylococcus aureus (brown) is one of the strains of staph that can cause sepsis.WIKIMEDIA, NIAIDWhen a subset of T cells tries to fend off toxins, or superantigens, secreted by common pathogenic bacteria, the response can be harmful, new research shows. Working with superantigens from strains of bacteria such as Staphylococcus and Streptococcus in mice and in cultured human cells, scientists found that when immune cells called mucosa-associated invariant T (MAIT) cells detect bacterial toxins, they pump out loads of inflammatory proteins—an immune response that may be the root of fatal illnesses, such as toxic shock syndrome and sepsis, the team reports today (June 20) in PLOS Biology.
“Our study has now unmasked a new, fast-acting, and extremely powerful culprit in the context of superantigens-mediated illnesses,” Mansour Haeryfar of Western University in London, Ontario, tells The Scientist in an email.
Until now, researchers thought well-documented T cells, such as CD4+ and CD8+ cells, were the primary source of proinflammatory proteins called cytokines, which contribute to the cytokine storm at the root of toxic shock, sepsis, and similar conditions. These cells respond relatively quickly to infection but researchers noticed an incredibly rapid response to superantigens, one that was perhaps too fast for CD4+ and CD8+ cells T cells to drive the initial cytokine release.
So Haeryfar and colleagues went looking for fast-acting T cells. The team targeted MAIT cells, which were first identified in ...
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