Welty, Nathan2016-09-192016-09-192014-09https://hdl.handle.net/11299/182228University of Minnesota Ph.D. dissertation. September 2014. Major: Microbiology, Immunology and Cancer Biology. Advisor: Daniel Kaplan. 1 computer file (PDF); xiv, 162 pages.Dendritic cells (DCs) in the intestinal lamina propria (LP) are composed of two CD103+ subsets that differ in CD11b expression. We report here that langerin is expressed by human LP DCs and that transgenic human langerin drives expression in CD103+ CD11b+ LP DCs in mice. This subset was ablated in huLangerin-DTA mice, resulting in reduced LP Th17 cells without affecting Th1 or T reg cells. Notably, cognate DC-T cell interactions were not required for Th17 development, as this response was intact in huLangerin-Cre I-Ab flox mice. In contrast, responses to intestinal infection or flagellin administration were unaffected by the absence of CD103+ CD11b+ DCs. huLangerin-DTA x BatF3-/- mice lacked both CD103+ LP DC subsets, resulting in defective gut homing and fewer LP T reg cells. Despite these defects in LP DCs and resident T cells, we did not observe alterations of intestinal microbial communities. Thus, CD103+ LP DC subsets control T cell homeostasis through both non-redundant and overlapping mechanisms.enadaptive immunitycommensaldendritic cellinnate immunitymucosal immunologyThesis or Dissertation