No abstract

A significant fall in plasma cholinesterase activity was observed in six healthy young women in the first 3 months of normal pregnancy. There was some evidence of return to normal pre-pregnancy levels in later pregnancy. No hypothesis is suggested to account for this phenomenon, although it seems possible that it may be the result of altered liver enzyme synthesis.

Innate lymphoid cells (ILC) play a significant role in the intestinal immune response and T-bet+ CD127+ group 1 cells (ILC1) have been linked to the pathogenesis of human inflammatory bowel disease (IBD). However, the functional importance of ILC1 in the context of an intact adaptive immune response has been controversial. In this report we demonstrate that induced depletion of T-bet using a Rosa26-Cre-ERT2 model resulted in the loss of intestinal ILC1, pointing to a post-developmental requirement of T-bet expression for these cells. Surprisingly, neither colonic intraepithelial ILC1, colonic lamina propria (cLP) ILC2 nor cLP ILC3 abundance were altered upon induced deletion of T-bet. Furthermore, Th1 polarization was not significantly altered upon induced T-bet deletion in vivo. Mechanistically, we report that STAT1 or STAT4 are not required for intestinal ILC1 development and maintenance. Mice with induced deletion of T-bet and subsequent loss of ILC1 were protected from the induction of severe colitis in vivo. Hence, this study provides support for the clinical development of an IBD treatment based on ILC1 depletion via targeting T-bet or its downstream transcriptional targets.

No abstract

Innate lymphoid cells (ILC) play a critical role in regulating immune responses at mucosal surfaces. Various subsets exist resembling T cell lineages defined by the expression of specific transcription factors. Thus, T-bet is expressed in ILC1 and Th1 cells. In order to further understand the functional roles of T-bet in ILC, we generated a fate-mapping mouse model that permanently marks cells and their progeny that are expressing, or have ever expressed T-bet. Here we have identified and characterised a novel ILC with characteristics of ILC1 and ILC2 that are fate-mapped for T-bet expression and arise early in neonatal life prior to establishment of a mature microbiome. These ILC1-ILC2 cells are critically dependent on T-bet and are able to express type 1 and type 2 cytokines at steady state, but not in the context of inflammation. These findings refine our understanding of ILC lineage regulation and stability and have important implications for the understanding of ILC biology at mucosal surfaces.