Anti-TREM1 monoclonal antibody, clone USFN-37 [PE]

AIM To investigate disease-specific gene expression profiles of peripheral blood mononuclear cells (PBMCs) from Crohn's disease (CD) patients in clinical remission. METHODS Patients with CD in clinical remission or with very low disease activity according to the Crohn's disease activity index were genotyped regarding nucleotidebinding oligomerization domain 2 (NOD2), and PBMCs from wild-type (WT)-NOD2 patients, patients with homozygous or heterozygous NOD2 mutations and healthy donors were isolated for further analysis. The cells were cultured with vitamin D, peptidoglycan (PGN) and lipopolysaccharide (LPS) for defined periods of time before RNA was isolated and subjected to microarray analysis using Clariom S assays and quantitative realtime PCR. NOD2- and disease-specific gene expression profiles were evaluated with repeated measure ANOVA by a general linear model. RESULTS Employing microarray assays, a total of 267 genes were identified that were significantly up- or downregulated in PBMCs of WT-NOD2 patients, compared to healthy donors after challenge with vitamin D and/or a combination of LPS and PGN (P < 0.05; threshold: >= 2-fold change). For further analysis by real-time PCR, genes with known impact on inflammation and immunity were selected that fulfilled predefined expression criteria. In a larger cohort of patients and controls, a disease-associated expression pattern, with higher transcript levels in vitamin D-treated PBMCs from patients, was observed for three of these genes, CLEC5A (P < 0.030), lysozyme (LYZ; P < 0.047) and TREM1 (P < 0.023). Six genes were found to be expressed in a NOD2 -dependent manner (CD101, P < 0.002; CLEC5A, P < 0.020; CXCL5, P < 0.009; IL-24, P < 0.044; ITGB2, P < 0.041; LYZ, P < 0.042). Interestingly, the highest transcript levels were observed in patients with heterozygous NOD2 mutations. CONCLUSION Our data identify CLEC5A and LYZ as CD- and NOD2 associated genes of PBMCs and encourage further studies on their pathomechanistic roles.

CD103(+)CD11b(+) dendritic cells (DCs) are unique to the intestine, but the factors governing their differentiation are unclear. Here we show that transforming growth factor receptor 1 (TGF beta beta R1) has an indispensable, cell intrinsic role in the development of these cells. Deletion of Tgfbr1 results in markedly fewer intestinal CD103(+)CD11b(+) DCs and a reciprocal increase in the CD103(-)CD11b(+) dendritic cell subset. Transcriptional profiling identifies markers that define the CD103(+)CD11b(+) DC lineage, including CD101, TREM1 and Siglec-F, and shows that the absence of CD103(+)CD11b(+) DCs in CD11c-Cre. Tgfbr1(fl/fl) mice reflects defective differentiation from CD103(-)CD11b(+) intermediaries, rather than an isolated loss of CD103 expression. The defect in CD103(+)CD11b(+) DCs is accompanied by reduced generation of antigen-specific, inducible FoxP3(+) regulatory T cells in vitro and in vivo, and by reduced numbers of endogenous Th17 cells in the intestinal mucosa. Thus, TGF beta R1-mediated signalling may explain the tissue-specific development of these unique DCs.