title: Effective chemokines and cytokines in the rejection of human retinal pigment epithelium (RPE) cell grafts.
abstract: OBJECTIVE
  In the rejection of transplanted retinal pigment epithelium (RPE) cells, an activation of allografts is probably the pivotal point for long-term success. The detailed immunological interactions involved in the rejection after RPE transplantation are still unknown. The aim of this study is to evaluate the interactions of pro-inflammatory cytokines and chemokines in this activation process in vitro.
  
  
  METHODS
  Human RPE cells (2 x 10(5)/ml) were therefore activated through a pre-treatment with different concentrations of interferon (IFN)-gamma (100 or 1000 U/ml), tumour necrosis factor (TNF)-alpha (1 or 10 ng/ml) or combinations of both, or employed in a nonactivated form. Afterwards, the RPE cells were tested by enzyme-linked immunosorbant assay (ELISA) and ribonuclease protection assays (RPA) for the secretion and mRNA content of the different chemokines (RANTES, MCP-1 and IL-8) and cytokines (IL-6) at various time points up to 48 h.
  
  
  RESULTS
  HRPE cells secrete the investigated cytokines in response to pro-inflammatory activation. This could be demonstrated at both the mRNA (RPA) and the protein levels (ELISA). The secretion was time and dose dependent, and significantly upregulated in comparison to that observed with nonactivated cells.
  
  
  CONCLUSIONS
  This study demonstrates that RPE cells efficiently secrete such cytokines as RANTES, MCP-1, IL-6, and IL-8, and have an accountable neutrophil and monocyte chemotactic activity. Thus, it could be indicated that the investigated cytokines play a central role in the activation cascade of RPE and in RPE rejection as well.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Leipzig, Germany. enzv@server3.medizin.uni-leipzig.de
authors.forename: V
authors.initials: V
authors.lastname: Enzmann
authors.forename: A
authors.initials: A
authors.lastname: Kaufmann
authors.forename: M
authors.initials: M
authors.lastname: Hollborn
authors.forename: P
authors.initials: P
authors.lastname: Wiedemann
authors.forename: D
authors.initials: D
authors.lastname: Gemsa
authors.forename: L
authors.initials: L
authors.lastname: Kohen
mesh_terms: D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D018946:Chemokine CCL5 / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006084:Graft Rejection / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology / Q000494:pharmacology; D015850:Interleukin-6 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016209:Interleukin-8 / Q000276:immunology / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000276:immunology* / Q000637:transplantation; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000494:pharmacology
chemical_list: D018932:Chemokine CCL2; D018946:Chemokine CCL5; D015850:Interleukin-6; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma