A study explaining how specific immune cells help to make transplanted donor tissue 'tolerable' is reported in the June 2006 issue of Nature Immunology. Much is known about how transplanted tissues are rejected, but exactly how the immune system learns to 'tolerate' transplants remained unclear.
Jordi Ochando and colleagues show that special immune cells called plasmacytoid dendritic cells acquire bits of transplanted heart tissue that are transported to the nearby lymph nodes. Once inside the lymph node, the plasmacytoid dendritic cells deliver signals to different resident immune cells that develop into cells that 'suppress' the possible activation of immune responses that can attack the transplanted tissue.
Precisely how the plasmacytoid dendritic cells induce the development of the suppressor cells is not known. However, these results might help us understand how the immune system is 'taught' to tolerate the presence of unfamiliar tissues.
Jordi Ochando (Mount Sinai School of Medicine, New York, NY, USA)
Jonathan Bromberg (Carl C. Icahn Center for Gene Therapy and Molecular Medicine, NY, USA)
Abstract available online.
(C) Nature Immunology press release.
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