Effect of leukocyte stimulation on rabbit immune complex glomerulonephritis

Effect of leukocyte stimulation on rabbit immune complex glomerulonephritis. Phytohemagglutinin (PHA), a leukocyte mitogen, induces a lymphocyte and blast cell glomerulonephritis in rat renal allografts (Cell Immunol 13:146, 1974). The aim of this study was to assess whether PHA similarly enhances rabbit monocyte-dependent experimental, acute immune complex glomerulonephritis, and whether this effect is associated with local release of interleukin-1 (IL-1) and tumor necrosis factor (TNF). Rabbits with experimental acute serum sickness (AcSS: Group I) had focal proliferative and exudative glomerulonephritis with immune deposits, scattered subepithelial electron-dense deposits (humps), mild and transient proteinuria, normal creatinine clearance and slightly increased production of IL-1 and TNF from isolated glomeruli. Rabbits with AcSS and injected with PHA (Group II) developed severe lymphocyte and blast cell glomerulonephritis with diffuse endothelial damage; immune deposits were significantly reduced, focal subepithelial electron-dense deposits were absent, proteinuria was increased, creatinine clearance was decreased and production of IL-1 and TNF was markedly augmented as compared to rabbits in Group I. Rabbits with AcSS and injected with IL-β and TNFα (Group V) had lesions comparable to those seen in Group II. These results show that PHA, IL-1 and TNF enhance the severity of acute immune complex glomerulonephritis, presumably by activating glomerular endothelial and mesangial cells and resident or infiltrated leukocytes

Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation

Human liver stem cells (HLSCs) are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs), and dendritic cells (DCs) in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2) and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs), HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response