Memory T cells present in Skin more Protective than Memory T Cells present in Blood Stream

A recent study, published in the journal Nature, has found that the resident memory T cells found predominantly in the skin are far more effective in providing immunity against infection compared to the memory T cells present in the blood stream. This comes as a total contrast to the earlier belief that the memory T cells present in the blood and lymph nodes play a major role in providing immunity against the invading bacteria and virus. The new study suggests that vaccination through the skin and other epithelial tissues invokes a stronger immune response than the circulating T cells and plays a fundamental role in the body’s immune system.

The study was led by Xiaodong Jiang, Rachael Clark and Thomas Kupper, researchers from the Brigham and Women’s Hospital in Boston. They compared the immunity provided by the resident T cells and the circulating T cells in different sets of mice after exposure to vaccinia virus. The researchers divided the laboratory mice into three groups: the first group had both resident and circulating T cells, the second group had only circulating T cells while the third group had only resident T cells. All the groups were re-infected with vaccinia virus. It was seen that both the groups of mice which had resident T cells, recovered from the infection within 6 days, whereas the mice which had only circulating T cells took around 20 days to recover from the infection.

The results clearly show that the resident memory T cells are far more effective in invoking a strong immune response compared to the circulating memory T cells. According to the researchers, the findings make sense as it is the skin and the epithelial tissue which first comes in contact with the invading bacteria and virus. The resident memory T cells not only concentrate at the site of infection but spread throughout the skin and remain there for around 6 months following the infection. The findings of the study may encourage the development of new class of vaccines which are injected and deliver through the epithelial tissue, and thereby provide greater degree of immunity against infections.

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Date: 
Thursday, March 1, 2012
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