Foxp3-Expressing CD103 super(+) Regulatory T Cells Accumulate in Dendritic Cell Aggregates of the Colonic Mucosa in Murine Transfer Colitis

• Published in: The American journal of pathology Vol. 168; no. 6; pp. 1898 - 1909
• Main Authors: Leithaeuser, F, Meinhardt-Krajina, T, Fink, K, Wotschke, B, Moeller, P, Reimann, J
• Format: Journal Article
• Language: English
• Published: 01-06-2006
• ISSN: 0002-9440
• DOI: 10.2353/ajpath.2006.050228

Little is known of the anatomical compartmentalization of colitogenic or regulatory T-cell responses in the murine transfer colitis model. Therefore, we analyzed the putative function of large intestinal dendritic cell (DC) aggregates, to which donor CD4 super(+)T cells selectively home before colitis becomes manifest. The co-stimulatory molecules MHC-II, CD40, CD80, and CD86 were expressed in DC aggregates. IL-23 was primarily absent from DC aggregates at all stages of disease but was expressed at high levels in the severely inflamed lamina propria. Interferon-g was up-regulated in the lamina propria during early and advanced disease, whereas in DC aggregates it was detectable to a significant degree only in fully developed colitis. In contrast, Foxp3, a marker of regulatory T cells, was expressed in DC aggregates on T-cell transfer, coinciding with the appearance of CE 103 super(+) CD25 super(-)T cells in these clusters. Foxp3 was enriched in the CD103 super(+) T-cell fraction isolated from the lamina propria of diseased mice. T-cell grafts depleted of CD103 super(+) T cells generated similar numbers of colonic CD103 super(+) T cells as unfractionated T cells. We conclude that DC aggregates are structures involved in the expansion and/or differentiation of CD103 super(+) CD25 super(-) CD4 super(+)Foxp3-expressing regulatory T cells.