Very recently, researchers discovered an important population ofimmune cells called memory T cells living in parts of the body thatare in contact with the environment (e.g., skin, lung, GI tract).How these “resident” memory T cells are generated was unknown, andtheir importance with regard to how our immune system remembersinfection and how it prevents against re-infection is being studiedintensively. Now, a study by a Brigham and Women’s Hospital (BWH) research teamled by Xiaodong Jiang, PhD, research scientist and Thomas S.Kupper, MD, Chair of the BWH Department of Dermatology, and theThomas B. Fitzpatrick Professor of Dermatology at Harvard, has useda model involving a vaccinia virus infection of the skin to answerimportant questions about how these newly discovered cells protectus. The study was electronically published on February 29, 2012 in Nature. Caterpillar Scanner
Jiang and Kupper used skin infection with vaccinia virus to studythe relative roles of central memory T cells (T cells thatcirculate in the bloodstream) and resident memory T cells inprotective immunity. What they found was that after infection,disease-specific T cells were rapidly recruited not only to theinfected site, but also to all areas of skin. They further showed that multiple additional infections at futuretime points led to an accumulation of even more of these residentmemory T cells in the skin, and that these cells remained in theskin for long periods of time. Finally, Jiang and Kupper showed, for the first time, that residentmemory T cells were the most important protective immune cells infighting infection – much more important than central memory Tcells, which were ineffective at rapid immune protection bythemselves. “Finding that resident memory T cells were so much more importantthan central memory T cells in protective immunity was surprising,and makes us re-think current immunologic dogma,” said Kupper. China Hino Diagnostic
While skin was used as a model system in this study, the resultscan be extrapolated to the lungs, GI tract, and other epithelialtissues that contact the outside world. The findings suggest that the most important elements of T cellmemory to infectious diseases may reside in tissues, rather than inthe blood. “The immune system provides the right T cells, at the right placeand time, to protect us from an environment that is full ofpotentially harmful pathogens.” said Kupper. Also, the findings imply that vaccines should be optimized tocreate precisely this kind of long lasting tissue-resident T cellimmunity, and that the current focus on antibody production may notbe as important. RGB Led Remote Control
“This work suggests a fundamental reassessment of how vaccines areboth constructed and delivered,” said Kupper. “These results havealtered the way we think about the immune system and vaccinationfor infectious diseases.” Additional References Citations.