Establishment and characterization of atypical fibroblasts from human adult liver contributing to hepatocyte cord-like arrangement.

We report the phenotypic and functional characterization of fibroblasts established in culture from the non-parenchymal epithelial cell populations of adult human livers. Human liver fibroblasts (hLF) expressed mesenchymal antigens vimentin, alpha-smooth muscle actin, collagen, fibronectin, CD73, CD90, CD105, and CD166 together with non-mesenchymal antigens cytokeratins 8 and 18, glial fibrillary acidic protein, and nestin. Mixed cell lineage-specific protein expression was not associated with stem-like cell properties.

Co expression of SCF and KIT in gastrointestinal stromal tumours (GISTs) suggests an autocrine/paracrine mechanism.

KIT is a tyrosine kinase receptor expressed by several tumours, which has for specific ligand the stem cell factor (SCF). KIT is the main oncogene in gastrointestinal stromal tumours (GISTs), and gain-of-function KIT mutations are present in 70% of these tumours. The aim of the study was to measure and investigate the mechanisms of KIT activation in 80 KIT-positive GIST patients.

Report on antibodies submitted to the stromal cell section of HLDA8.

The paradigm for tissue specific homing of leukocytes is the "area code" hypothesis, which predicts that a specific combination of adhesive interactions and chemokine signals from the endothelium directs leukocyte migration into specific tissue sites. This area code hypothesis has been supported by studies from previous HLDA workshops where endothelial specific cell antigens have been studied. Similarly, a clear haematopoietic "stem cell code" comprising the chemokine SDF-1 (CXCL12) and the adhesion receptor VCAM-1 (CD106) has been shown to contribute to the stem cell niche within bone marrow [K.

Membrane-bound and soluble IL-15/IL-15Ralpha complexes display differential signaling and functions on human hematopoietic progenitors.

Membrane-bound and soluble interleukin-15 (IL-15)/IL-15 receptor alpha (Ralpha) complexes trigger differential transcription factor activation and functions on human hematopoietic progenitors. Indeed, human spleen myofibroblasts (SMFs) are characterized by a novel mechanism of IL-15 trans-presentation (SMFmb [membrane-bound]-IL-15), based on the association of an endogenous IL-15/IL-15Ralpha complex with the IL-15Rbetagamma c chains. SMFmb-IL-15 (1) induces lineage-specific signaling pathways that differ from those controlled by soluble IL-15 in unprimed and committed normal progenitors; (2) triggers survival and proliferation of leukemic progenitors expressing low-affinity IL-15R (M07Sb cells); (3) causes only an antiapoptotic effect on leukemic cells expressing high-affinity receptors (TF1beta cells).