Cytomegalovirus- and interferon-related effects on human endothelial cells. Cytomegalovirus infection reduces upregulation of HLA class II antigen expression after treatment with interferon-gamma.
ABSTRACT Cultured human umbilical vein endothelial cells (HUVEs) were infected with human cytomegalovirus (HCMV) strain AD169. Up to 50% HUVEs proved to be positive for HCMV early nuclear antigens 24 hours after inoculation with virus. Following infection kinetics of surface expression of HLA class I and II, intercellular adhesion molecule (ICAM-1) and endothelial lymphocyte adhesion molecule (ELAM-1) on HUVEs were investigated by means of flow cytometry. A slight increase in HLA class I expression was observed, whereas expression of HLA class II (DR, DP, DQ) antigens was not induced by infection with HCMV. Furthermore, when compared with uninfected cells treated with interferon-gamma (IFN-gamma), reduced enhancement of HLA-DR expression was conspicuous in HCMV-infected cells treated with IFN-gamma. There is evidence that only a portion of HUVE is affected in its ability to upregulate HLA class II antigens. While expression of ICAM-1 was found to be enhanced between 8 and 20 hours after infection with a maximum at 12 hours after infection, no modulation of ELAM-1 was seen.
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ABSTRACT: Background. Cytomegalovirus (CMV) has been associated with the development, of chronic allograft rejection, Attempts to delineate pathogenetic mechanisms for this association have characteristically used well-established laboratory strains for in vitro investigation and rodent strains for in vivo studies. There is substantial genetic heterogeneity not only among different laboratory strains, but also between laboratory strains and clinical isolates, and genetic differences between human and animal strains arte profound. Given these genetic differences, one would anticipate differences in biological activity between strains, Methods. Vascular endthelial cells were infected with two laboratory strains of CMV (Towne and AD-169) as well as two individual clinical CMV isolates, after genetic typing with six segments of the genome (including early and late genes). mRNA expression coding for a panel of mesenchymal growth factors was studied using quantitative reverse transcription, polymerase chain reaction. Major histocompatibility complex (MHC) expression was investigation using flow cytometry. Results. There was substantial genetic variability bet clinical and laboratory isolates. There did not appear to be differences in overall infectivity by the different strains as determined by expression of immediate-early antigen at 24 hours (5-10% of endothelial cells positive for immediate-early. Two growth factors, platelet-derived growth factor-A and basic fibroblast growth factor were augmented;ed by sine of the two clinical strains of CMV (Clin 2) (P=0.0091 and P=0.0018, respectively). Transforming growth factor-alpha and insulin-like growth factor expression were significantly reduced by both clinical strains and AD-169. Two other growth factors, heparin-binding epidermal growth factor and transforming growth factor-beta were not altered by infection with any strain, No strain altered MHC class II expression. MHC class I expression was increased with one of the clinical strains (Clin 1, P=0.0006) and decreased by AD-169 (P=0.0016). Clin 2 and Towne had no effect on MHC Class I expression. Conclusions. These data demonstrate that the genetic heterogeneity of CMV is associated with differences in transplant-relevant biologic activity even among clinical isolates. The relationship between CMV and chronic rejection may be difficult to determine given the heterogeneous nature of this complex virus.Transplantation 11/1999; 68(10):1568-1573. DOI:10.1097/00007890-199911270-00022 · 3.78 Impact Factor
Klinische Pädiatrie 01/1999; 211(04):310-313. DOI:10.1055/s-2008-1043806 · 1.90 Impact Factor
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ABSTRACT: The endothelium represents an important therapeutic target for containment of oxidative stress, thrombosis and inflammation involved in a plethora of acute and chronic conditions including cardiovascular and pulmonary diseases and diabetes. However, rapid blood clearance and lack of affinity to the endothelium compromise delivery to target and restrict medical utility of antioxidant enzymes (e.g., catalase) and fibrinolytics. The use of "stealth" PEG-liposomes prolongs circulation, whereas conjugation with antibodies to endothelial determinants permits targeting. Constitutive endothelial cell adhesion molecules (CAM, such as ICAM-1 and PECAM-1, which are stably expressed and functionally involved in oxidative stress and thrombosis) are candidate determinants for targeting of antioxidants and fibrinolytics. CAM antibodies and compounds conjugated with anti-CAM bind to endothelial cells and accumulate in vascularized organs (preferentially, lungs). Pathological stimuli enhance ICAM-1 expression in endothelial cells and facilitate targeting, whereas PECAM-1 expression and targeting are stable. Endothelial cells internalize 100-300 nm diameter conjugates possessing multiple copies of anti-CAM, but not monomolecular antibodies or micron conjugates. This permits size-controlled sub-cellular targeting of antioxidants into the endothelial interior and fibrinolytics to the endothelial surface. Targeting catalase to PECAM-1 or ICAM-1 protects endothelial cells against injury by oxidants in culture and alleviates vascular oxidative stress in lungs in animals. Anti-CAM/catalase conjugates are active for a few hours prior to lysosomal degradation, which can be delayed by auxiliary drugs. Conjugation of fibrinolytics to monovalent anti-ICAM permits targeting and prolonged retention on the endothelial surface. Therefore, CAM targeting of antioxidants and fibrinolytics might help to contain oxidative and thrombotic stresses, with benefits of blocking CAM. Avenues for improvement and translation of this concept into the clinical domain are discussed.Current Pharmaceutical Design 07/2005; 11(18):2383-2401. DOI:10.2174/1381612054367274 · 3.29 Impact Factor