BOSTON A group of "color-coded" laboratory mice are providing researchers with a novel way of tracking T-cells, enabling them to visualize and monitor the cellular immune responses of transplanted tissue in real time. The new imaging system is described in the June issue of Nature Medicine, which appears on-line this week.
"These immune responses are a key consideration in developing strategies to improve transplant outcomes," explains co-senior author Terry Strom, MD, Co-director of the Transplant Institute at Beth Israel Deaconess Medical Center (BIDMC) and Professor of Medicine at Harvard Medical School (HMS). "The fate of a transplant following withdrawl of immunosuppressive therapy either rejection or tolerance is thought to be dependent upon the balance of destructive and protective T cells. With this new system, we can actually visualize this balance."
The acquisition of tolerance a state in which transplanted tissue is not rejected by the body even in the absence of immunosuppressive therapy is dependent upon several subsets of T cells, including protective regulatory T cells (Tregs) and destructive effector T cells (Teffs).
"The issue of whether newly transplanted tissue is attacked or protected is not a black-and-white situation," explains Strom. "Even when transplants are rejected, there will be some protective Treg cells present. And, conversely, in cases of tolerance when the new transplant is accepted there will still be some aggressive Teff cells at the scene of the crime." But, because it has not been possible for scientists to readily distinguish these two T cell subsets in vivo, the relative importance of these different types of T cells in the induction and maintenance of transplant tolerance has been unclear.
To address this issue, the BIDMC transplant immunology team, led by Strom and Maria Koulmanda, PhD, Associate Professor of Surgery at HMS, first created two mouse models one that wo
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Beth Israel Deaconess Medical Center