Purpose Human interleukin-21 (IL-21) is a class I cytokine previously reported in clinical studies on immune responsive cancers. Here we report the eVects of systemic IL-21 therapy on the immune system in two phase 1 trials with this novel cytokine. Experimental design Recombinant IL-21 was administered by intravenous bolus injection at dose levels from 1 to 100 g/kg using two planned treatment regimens: thrice weekly for 6 weeks (3/week); or once daily for Wve consecutive days followed by nine dose-free days (5 + 9). The following biomarkers were studied in peripheral blood mononuclear cells (PBMC) during treatment: phosphorylation of STAT3, alterations in the composition of leukocyte subsets, ex vivo cytotoxicity, expression of eVector molecules in enriched CD8 + T cells and CD56 + NK cells by quantitative RT-PCR, and gene array proWling of CD8 + T cells. Results EVects of IL-21 were observed at all dose levels. In the 5 + 9 regimen IL-21 induced a dose dependent decrease in circulating NK cells and T cells followed by a return to baseline in resting periods. In both CD8 + T cells and CD56+ NK cells we found up-regulation of perforin and granzyme B mRNA. In addition, full transcriptome analysis of CD8 + T cells displayed changes in several transcripts associated with increased cell cycle progression, cellular motility, and immune activation. Finally, cytotoxicity assays showed that IL-21 enhanced the ability of NK cells to kill sensitive targets ex vivo. Conclusions IL-21 was biologically active at all dose levels administered with evidence of in vivo NK cell and CD8 + T cell activation.

IBD and experimental murine colitis have a high degree of similarity in the colonic transcriptional profile, probably secondary to non-specific inflammatory processes. However, differences do exist between models, emphasising the need for careful selection and interpretation of qualified animal models in preclinical research.

Hemophilia A (HA) is a bleeding disorder resulting from deficient Factor VIII (FVIII), which normally functions as a cofactor to activated Factor IX (FIXa) that facilitates activation of Factor X (FX). To mimic this property in a bispecific antibody (biAb) format, a screening was conducted to identify functional pairs of anti-FIXa and anti-FX antibodies, followed by optimization of functional and biophysical properties. The resulting biAb (Mim8) assembled efficiently with FIXa and FX on membranes, and supported activation with an apparent equilibrium dissociation constant (KD) of 16 nM. Binding affinity with FIXa and FX in solution was much lower, with KD-values for FIXa and FX of 2.3 and 1.5 µM, respectively. In addition, the activity of Mim8 was dependent on stimulatory activity contributed by the anti-FIXa arm, which enhanced the proteolytic activity of FIXa by four orders of magnitude. In hemophilia A plasma and whole blood, Mim8 normalized thrombin generation and clot formation with potencies 13 and 18 times higher than a sequence-identical analog of emicizumab, respectively. A similar potency difference was observed in a tail-vein transection model in hemophilia A mice, while reduction of bleeding in a severe tail-clip model was observed only for Mim8. Furthermore, the pharmacokinetics of Mim8 were investigated and a half-life of 14 days demonstrated in cynomolgus monkey. In conclusion, Mim8 is a FVIIIa-mimetic with a potent and efficacious hemostatic effect based on preclinical data.

We demonstrate that IL-33, GLP-1R, and CCL20 are deregulated in human IBD, and that prophylactic treatment with 0.6 mg/kg liraglutide improves disease in AdTr colitis. In addition, GLP-1 receptor agonists upregulate IL-33, mucin 5b, and CCL20 in murine Brunner's glands. Taken together, our data indicate that GLP-1 receptor agonists affect gut homeostasis in both proximal and distal parts of the gut.

To understand the ability of regulatory T-cells to control diabetes development in clinically relevant situations, we established a new model of accelerated diabetes in young DP-BB rats by transferring purified T-cells from DR-BB rats made acutely diabetic. Transfer of 3, 5, 10, or 23 million pure in vitro؊activated T-cells accelerated diabetes onset in >90% of the recipients, with the degree of acceleration being dosage dependent. Cotransfer of unfractionated leukocytes from healthy donors prevented diabetes. Full protection was achieved when protective cells were transferred 3-4 days before diabetogenic cells, whereas transfer 2 days before conferred only partial protection. Protection resided in the CD4 ؉ fraction, as purified CD4 ؉ T-cells prevented the accelerated diabetes. When CD25 ؉ cells were depleted from these cells before they were transferred, their ability to prevent diabetes was impaired. CD25ϩ cells prevent Th1-and Th2-induced colitis as well as Leishmania major infection (10), control active experimental autoimmune encephalomyelitis (11), and ameliorate established colitis (12).In the NOD mouse model of human type 1 diabetes, regulatory T-cells were first defined as a subpopulation of cells expressing CD4 ϩ CD45RB low or CD4 ϩ CD62L ϩ (13-15). Later, these regulatory T-cells were shown to coexpress CD62L and CD25 (16).In the other spontaneous model of type 1 diabetes, the DP-BB, regulatory cells have not been characterized with regard to their expression of CD25. Previously, spontaneous disease was prevented by a single transfer of spleen cells (17) and the prevention was enhanced by enrichment for CD4 ϩ cells (18). However, transfer of leukocytes from normal rats has so far been successful only if the transfer takes place before the initiation of insulitis (i.e., at about age 1 month) (17,19); transfers conducted at 2 months accelerate diabetes (19). Protection is dependent on the engraftment of the ART2 ϩ (formerly RT6) cells (20); in the control strain, the DR-BB, depletion of these induces diabetes (21). We recently showed that accelerated diabetes induced by the transfer of in vitro phorbol myristate acetate (PMA) plus ionomycinϪactivated unfractionated splenocytes from acutely diabetic donors is delayed by transfer of DR-BBϪderived leukocytes (22).In this study, we proposed to prevent diabetes using a new rat model where diabetes onset was accelerated by transfer of pure, in vitro PMA plus ionomycinϪactivated T-cells; that is, without activated antigen-presenting cells as were used in our previous study (22). Using preactivated diabetogenic T-cells in the current study allowed us to explore a situation that is relevant to understanding how such already activated T-cells can be controlled in patients with ongoing ␤-cell destruction. Establishing the conditions required for preventing diabetes by cotransferring various leukocytes from healthy DR-BB rats allowed us to narrow a powerful regulatory potential to CD4 ϩ CD25 ϩ T-cells. This new model in rats is well suited to testing preventive s...

Intestinal epithelial cells (IECs) are one of a few cell types in the body with constitutive surface expression of natural killer group 2 member D (NKG2D) ligands, although the magnitude of ligand expression by IECs varies. Here, we investigated whether the gut microbiota regulates the NKG2D ligand expression on small IECs. Germ-free and ampicillin-treated mice were shown to have a significant increase in NKG2D ligand expression. Interestingly, vancomycin treatment, which propagated the bacterium Akkermansia muciniphila and reduced the level of IFN-γ and IL-15 in the intestine, decreased the NKG2D ligand expression on IECs. In addition, a similar increase in A. muciniphila and a decreased NKG2D ligand expression was seen after feeding with dietary xylooligosaccharides. A pronounced increase in NKG2D ligand expression was furthermore observed in IL-10-deficient mice. In summary, our results suggest that the constitutive levels of NKG2D ligand expression on IECs are regulated by microbial signaling in the gut and further disfavor the intuitive notion that IEC NKG2D ligand expression is caused by low-grade immune reaction against commensal bacteria. It is more likely that constitutively high IEC NKG2D ligand expression is kept in check by an intestinal regulatory immune milieu induced by members of the gut microbiota, for example A. muciniphila. Keywords:Gut microbiota r IL-10 r Intestinal epithelial cells r NKG2D ligands IntroductionCommensal bacteria are important in maintaining immune tolerance and intestinal epithelial barrier integrity. As such, the commensal microbiota is an integral part of the normal gut. It is tolerated by the mucosal immune system [1], which however may rapidly switch from its suppressive state to become activated upon pathogen engagement [2]. The natural killer group 2 member D (NKG2D)/NKG2D ligand interaction is part of this immunological sensor system that detects malfunctioning. Chronic inflammatory Correspondence: Dr. Camilla H. F. Hansen e-mail: camfriis@sund.ku.dk conditions in the gut such as the autoimmune celiac disease and Crohn's disease in humans, and colitis in mice, are associated with increased surface expression of NKG2D ligands on intestinal epithelial cells (IECs) and lamina propria dendritic cells [3][4][5][6] which is also observed after infection with certain pathogenic strains of Escherichia coli [7].NKG2D ligands belong to the nonclassical MHC class I molecules and include MICA, MICB, and ULBP 1-6 proteins in human [8,9] and the H60a/-b/-c, Rae-1, and Mult1 proteins in mice [10]. Their expression levels are generally low, but are greatly enhanced during specific types of cellular stress, including inflammation and neoplastic transformation [11]. IECs were recognized early on as one of the few cell types in the body with constitutive surface expression of NKG2D ligands [12]; however, The regulation of NKG2D ligand surface expression has been intensely studied. However, a unifying controlling mechanism, if one exists, has not yet been established. It is clear that NK...

The study demonstrates that intestinal IL-33 is capable of inducing GATA-3 in mucosal T cells, and suggests that IL-33 is a key mediator of pathological TH2 and non-TH2-type responses in intestinal inflammation. Blocking IL-33 signaling could be a feasible option in the treatment of UC.

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