Publication Date:
2011-11-18
Description:
Abstract 821 Regulatory T cells defined as CD4+ and expressing the transcription factor Foxp3 have been shown to play a pivotal role in mitigating the severity of graft versus host disease (GVHD). In the course of studies designed to define the functional role of various CD4+ Treg populations in GVHD biology, we identified a novel population of CD8+ T cells that expressed Foxp3 and were induced early during this disease. While this population has been reported in patients with autoimmune disorders, the role of CD8+ Foxp3+ T cells in GVHD is unknown. To delineate the significance of this observation, we performed studies in which lethally irradiated Balb/c [H-2d] mice were transplanted with bone marrow and spleen cells from C57BL/6J [H-2b] mice that carried an EGFP reporter gene linked to Foxp3 (Foxp3EGFP). Tissues (spleen, lung, liver and colon) were harvested 5, 7, 10, 14 and 21 days post transplantation to define the temporal kinetics and absolute numbers of CD8+ Tregs during acute GVHD. We observed that CD8+ Foxp3+ T cells were detectable as early as five days post transplantation and persisted for up to three weeks in all GVHD target tissues. This cell population was present in similar percentages and absolute numbers to CD4+ Tregs in these tissue sites which is noteworthy given that the CD4+ Treg pool is comprised of two populations (natural Tregs and induced Tregs) whereas the CD8 pool is made up almost exclusively of Tregs that are induced, since only a very small percentage of CD8+ T cells from normal mice (
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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