CD161+ T (NT) cells exist predominantly in human intestinal epithelium as well as in liver

Abstract

SUMMARYIt has been reported that human CD161 (NKR-P1A) + T cells are counterparts of murine natural T (NT) cells and predominantly accumulate in the liver. However, NT cells in the human intestine have not been well analysed. The aim of this study was to assess the existence of NT cells in human intestinal epithelium and determine their phenotypical characterization. Intra-epithelial lymphocytes (IEL) were isolated from surgical specimens (jejunum, ileum and colon). The surface phenotype of IEL was analysed using a FACScan and compared with that of mononuclear cells (MNC) from other organs. CD161 + T cells were abundant in human intestinal epithelium as well as the liver. The majority of CD161 + T cells in IEL were CD8 + cells. About 50% of CD161 + T cells in hepatic lymphocytes (HL) expressed CD56, whereas only 14% of CD161 + T cells in IEL expressed CD56. The jejunum showed the greatest abundance of CD161 + T cells among the intestinal regions investigated. These results suggest that CD161 + T (NT) cells predominantly exist in human intestinal epithelium and may play an important role in local immunity.

Expression of CD161 (NKR-P1A) Defines Subsets of Human CD4 and CD8 T Cells with Different Functional Activities

“…The latter cells contained few, if any, V␣24V␤11 invariant NK T cells and secreted IFN-␥ and TNF-␣ without IL-4 after in vitro stimulation. An abundance of CD161 ϩ T cells was also found in the liver and intestinal epithelial cells of the jejunum; the majority of the latter cells were CD161 ϩ CD8 ϩ T cells (15). CD161 is also expressed on human monocytes and dendritic cells (16).…”

CD56 Marks an Effector T Cell Subset in the Human Intestine

“…In humans, several functionally distinct T cell populations have been reported in the gut mucosa, such as T cells expressing NK markers (16). For instance, intestinal T cells expressing CD161 were recently reported to express proinflammatory cytokines (17), whereas a second population of mucosal T cells expresses CD56 (18), a marker which may identify proinflammatory T cells in the liver (19,20).…”

The Influence of Colonic Irrigation on Human Intestinal Microbiota

“…The intestine is an important site of local immunity and nutrition (Iiai et al, 2002). It is a major site of extrathymic T cell differentiation, and numerous activated and quiescent lymphocytes are produced within GALT.…”