9 research outputs found
Transforming growth factor-β1 regulates chemokine and complement production by human proximal tubular epithelial cells
Transforming growth factor-γ1 regulates chemokine and complement production by human proximal tubular epithelial cells. Previously it has been demonstrated that human proximal tubular epithelial cells (PTEC) are able to produce chemokines (such as IL-8 and MCP-1) and complement components (such as C2, C3, C4 and factor H), and that production of these proteins is regulated by pro-inflammatory cytokines such as interleukin-1α (IL-1α), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). Since TGF-γ is also expressed in the renal interstitium during inflammation, we investigated the effect of TGF-γ on the production of chemokines and complement components by PTEC in culture. Transforming growth factor-γ1 up-regulated IL-8 production by an average of 4.11 ± 1.0-fold. macrophage chemoattractant phagocyte (MCP-1) production, on the other hand, was down-regulated by TGF-γ1 by an average of 2.2 ± 0.7-fold. The production of C3 and C4 was also down-regulated after incubation with TGF-γ1 (1.9 ± 0.3- and 3.0 ± 1.2-fold, respectively). All effects were dose- and time-dependent and were found to be specific for TGF-γ1, as assessed by inhibition of the effect with a neutralizing antibody against TGF-γ1. These data, together with the knowledge that TGF-γ, chemokines and complement components play a role in several types of renal disease, suggest that TGF-γ is involved in the regulation of local expression of chemokines and complement components by tubular cells
High throughput screening for antibody induced complement-dependent cytotoxicity in early antibody discovery using homogeneous macroconfocal fluorescence imaging
Complement-dependent cytotoxicity (CDC) represents an important Fc-mediated effector function of antibodies and is a quality often sought in candidates for therapeutic antibody development in cancer. Antibodies inducing potent CDC are relatively rare as the ability to induce CDC is strongly dependent on the antigen and epitope recognized as well as antibody isotype. To allow the identification of antibodies with optimal CDC characteristics in early stages of antibody discovery, we developed a homogeneous high throughput CDC assay, compatible with 384 and 1536 well formats and which therefore allows direct functional screening of very large panels of antibodies. Results obtained with our newly developed CDC method are consistent with those obtained with conventional assays. The assay proved to be robust, reliable over a wide reading window, easy to perform with low hands-on, high throughput, cost effective and applicable to crude hybridoma samples as typically available in early hybridoma discovery. In conclusion, we developed a novel high throughput assay for the identification of therapeutic antibody lead candidates with optimal CDC characteristics from large antibody libraries. (C) 2009 Elsevier B.V. All rights reserved
High-Throughput Screening for Internalizing Antibodies by Homogeneous Fluorescence Imaging of a pH-Activated Probe
Resolution of psoriasis upon blockade of IL-15 biological activity in a xenograft mouse model
Psoriasis is a chronic inflammatory disease of the skin characterized by epidermal hyperplasia, dermal angiogenesis, infiltration of activated T cells, and increased cytokine levels. One of these cytokines, IL-15, triggers inflammatory cell recruitment, angiogenesis, and production of other inflammatory cytokines, including IFN-γ, TNF-α, and IL-17, which are all upregulated in psoriatic lesions. To investigate the role of IL-15 in psoriasis, we generated mAb’s using human immunoglobulin-transgenic mice. One of the IL-15–specific antibodies we generated, 146B7, did not compete with IL-15 for binding to its receptor but potently interfered with the assembly of the IL-15 receptor α, β, γ complex. This antibody effectively blocked IL-15–induced T cell proliferation and monocyte TNF-α release in vitro. In a human psoriasis xenograft model, antibody 146B7 reduced the severity of psoriasis, as measured by epidermal thickness, grade of parakeratosis, and numbers of inflammatory cells and cycling keratinocytes. These results obtained with this IL-15–specific mAb support an important role for IL-15 in the pathogenesis of psoriasis
Dual Mode of Action of a Human Anti-Epidermal Growth Factor Receptor Monoclonal Antibody for Cancer Therapy
A novel human CD32 mAb blocks experimental immune haemolytic anaemia in Fc gamma RIIA transgenic mice
A fully human IgG1 kappa antibody (MDE-8) was generated, which recognised Fc-gamma receptor IIa (Fc?RIIa) molecules on CD32 transfectants, peripheral blood monocytes, polymorphonuclear cells and platelets. This antibody blocked Fc?RIIa ligand-binding via its F(ab')2 fragment. Overnight incubation of monocytes with F(ab')2 fragments of MDE-8 leads to a c. 60% decrease in cell surface expression of Fc?RIIa. MDE-8 whole antibody induced a concomitant c. 30% decrease of Fc?RI on THP-1 cells and monocytes. In humans Fc?RIIa plays an important role in the clearance of antibody-coated red blood cells in vivo. As an equivalent of Fc?RIIa does not exist in mice, the in vivo effect of MDE-8 was studied in an Fc?RIIa transgenic mouse model. In these mice, antibody-induced anaemia could readily be blocked by MDE-8. These data document a new human antibody that effectively blocks Fc?RIIa, induces modulation of both Fc?RIIa and Fc?RI from phagocytic cells, and ameliorates antibody-induced anaemia in vivo