Mit Selbstkritik durch den Mediendschungel. Die Strukturen des deutschen Medienjournalismus und das Selbstverständnis der Medienredakteure

Die Medien sind heute allgegenwärtig - sei es in Gesellschaft und Politik, sei es in Wirtschaft oder Kultur. Das Schlagwort von der Mediengesellschaft vermag den beachtlichen Bedeutungsaufschwung, den die Medien, allen voran das Fernsehen, während der letzten Jahre erfahren haben, anzudeuten: Die Medien moderieren den gesellschaftlichen Diskurs; sie vermitteln Politik und sii:J.d damit zu einem absolut notwendigen "Unterpfand der Demokratie"! geworden. Daneben hat sich die Medienindustrie zu einer gigantischen Wachstumsbranche entwickelt, die pro Jahr immense Summen umsetzt und in Zeiten einer weitläufig stagnierenden Ökonomie gegen den allgemeinen Trend sogar Arbeitsplätze schafft. Der Wirkungskreis der Medien reicht aber über die Bereiche Politik und Wirtschaft weit hinaus - die Medien haben sich in der modernen Gesellschaft zur sprichwörtlichen "Bewusstseinsindustrie" entwickelt: Sie sind es, die unseren Alltag bestimmen_ Sie prägen unsere Gedanken und Vorstellungen. Sie beeinflussen unser Verhalten und unsere Gewohnheiten. Damit hat die Welt der Medien, erneut allen voran das Fernsehen, eine "weitreichende Definitionsmacht über die Wirklichkeit gewonnen", und das nicht nur nach Auffassung des hier zitierten französischen Soziologen und Fernsehkritikers Pierre Bourdieu. (...) EnglishThomas Linke/Daniela Pickl: Self-critical journalism in the media-jungleDuring the last decade the media scene in Germany has been so widely diversificated that it is often called a media-jungle. The media themselves, now, reacted to this tendency by more and more making their own scene to a subject matter. In this way, a new kind of journalism emerged: media-journalism. While university studies on this topic in general are still in the beginnings, at the faculty for Journalism II of the Catholic University of Eichstärt in the Wintersemester 1998/99 two degree dissertations were written: one as an opinion poll and one as an analysis of content. In the opinion poll editors of all media sections in Germany were especially questioned concerning their self-understanding while the content analysis tried to find out about the quality of media-reporting in selected newspapers. Both researches concentrated on the question which conception of media-journalism is favoured in Germany. The answer was alike in both cases: Most frequently the integrational approach is chosen collecting all media themes on one page. On second place follows the crossection model: distributing media themes - either by purpose or due to financial and personal circumstances - all over the issue. In addition, in Germany at present a positive tendency is to be found: More and more newspapers install own media editors.

Scheme and functional evaluation of IL-2v.

<p>(<b>A</b>) Scheme of mutations introduced into IL-2v. IL-2 loss-of-function mutation (black asterisk), IgG-binding mutant (white asterisk). (<b>B</b>) Biological activity of IL-2v. IL-2 dependent HT-2 cells were incubated with titrated amounts of VNP decorated with either IL-2::GPI, IL-2::2IgGPI or their p.C72A mutated relatives IL-2(A)::GPI, IL-2::2Ig(F)GPI and IL-2(A)::2Ig(F)GPI, or alternatively recombinant IL-2 and analyzed for proliferation. ED₅₀ values for IL-2::GPI (dashed black line), IL-2::2IgGPI (dashed red line), IL-2::2Ig(F)GPI (dashed blue line) decorated VNP are indicated. (<b>C</b>) Amounts of particles required to induce half maximal proliferation rates in HT-2 cells. (<b>D</b>) Flow cytometry analysis of IgG binding to HEK-293 cells transfected with indicated constructs. Figure shows percent reduction of Ig binding compared to unmodified molecules. Data are representative (B) or show the summary (C, D) of eleven (IL-2::GPI), seven (IL-2::2IgGPI) and six (IL-2::2Ig(F)GPI, IL-2(A)::GPI, IL-2(A)::2Ig(F)GPI and recombinant IL-2) (B), eleven (IL-2::GPI), seven (IL-2::2IgGPI) and six (IL-2::2Ig(F)GPI) (C) and five (except four IL-2(A)::2Ig(F)GPI) (D) independent experiments. * p < 0.05, **, p < 0.01, ***, p < 0.001; ANOVA and Tukey’s multiple comparison test (C) and Kruskal-Wallis test and Mann-Whitney U-test followed by post hoc Bonferroni correction (D).</p

CD8⁺ T Cell Fate and Function Influenced by Antigen-Specific Virus-Like Nanoparticles Co-Expressing Membrane Tethered IL-2

<div><p>A variety of adjuvants fostering humoral immunity are known as of today. However, there is a lack of adjuvants or adjuvant strategies, which directly target T cellular effector functions and memory. We here determined whether systemically toxic cytokines such as IL-2 can be restricted to the site of antigen presentation and used as ‘natural adjuvants’. Therefore, we devised antigen-presenting virus-like nanoparticles (VNP) co-expressing IL-2 attached to different membrane-anchors and assessed their potency to modulate CD8⁺ T cell responses <i>in vitro</i> and <i>in vivo</i>. Efficient targeting of IL-2 to lipid rafts and ultimately VNP was achieved by fusing IL-2 at its C-terminus to a minimal glycosylphosphatidylinositol (GPI)-anchor acceptor sequence. To identify optimal membrane-anchor dimensions we inserted one (1Ig), two (2Ig) or four (4Ig) immunoglobulin(Ig)-like domains of CD16b between IL-2 and the minimal GPI-anchor acceptor sequence of CD16b (GPI). We found that the 2IgGPI version was superior to all other evaluated IL-2 variants (IL-2v) in terms of its i) degree of targeting to lipid rafts and to the VNP surface, ii) biological activity, iii) co-stimulation of cognate T cells in the absence of bystander activation and iv) potency to induce differentiation and acquisition of CD8⁺ T cell effector functions <i>in vitro</i> and <i>in vivo</i>. In contrast, the GPI version rather favored memory precursor cell formation. These results exemplify novel beneficial features of membrane-bound IL-2, which in addition to its mere T cell stimulatory capacity include the induction of differential effector and memory functions in CD8⁺ T lymphocytes.</p></div

Strong CD8⁺ T cell effector functions induced by IL-2::2Ig(F)GPI asVNP.

<p>(<b>A</b>) Flow cytometry analysis showing proliferation and intracellular IFN-γ-expression of CFSE-labeled CD8^<b>+</b> TCR Vα2^<b>+</b> T-cells. Markers set according to negative stainings and no-stimulation control. Numbers indicate percentage of cells in respective quadrants. (<b>B</b>) Flow cytometry analysis, (<b>C</b>) percentage and (<b>D</b>) fold-induction of IFN-γ producing CD8^<b>+</b> T cells in the absence or presence of indicated stimuli. (<b>E</b>) Amounts of IFN-γ (pg/ml) secreted upon co-culture of CD8^<b>+</b> T cells with indicated IL-2v asVNP or αCD3/αCD28 coated microbeads plus IL-2 (10 or 100 U/ml). (<b>F-H</b>) IL-2::2Ig(F)GPI asVNP increase the cytotoxic potential of antigen-specific T cells. P14 splenocytes were stimulated with IL-2v asVNP for 48 hours or left untreated and were subsequently co-cultured with 1x10^<b>4</b> wt (CPD^{<b>bright</b>}) or LCMV-GP expressing (CPD^<b>dim</b>) EL-4 target cells. Specific target cell lysis was analyzed after 20 hours by flow cytometry. (<b>F</b>) Flow cytometry analysis showing specific lysis of LCMV-GP^<b>+</b> but not wt target cells at an effector/target ratio of 10. (<b>G</b>) Quantification by flow cytometric analysis of specific target cell lysis relative to maximum lysis (LCMV-GP_33-41 stimulated effector cells, E:T ratio 20:1). (<b>H</b>) Determination of cytotoxic potential in ^<b>51</b>Cr-release assays of P14 splenocytes, which were stimulated with IL-2v asVNP or left untreated for 48 hours. Effector cells were co-cultured with ^<b>51</b>Cr-labelled wildtype or LCMV-GP-expressing EL-4 target cells (1x10^<b>4</b>) and specific lysis was analyzed. Data are representative (A, B, F, H) or show the summary (C, D, E, G) of three (A, B, F, G), five (except three for αCD3/αCD28 microbeads) (C, D), four (except two for 48 and 72 hrs) (E) and triplicates of one (H) independent experiments. * p < 0.05, **, p < 0.01, ***, p < 0.001; ANOVA and Tukey’s multiple comparison test (C, D), Kruskal-Wallis test and Mann-Whitney U-test and Bonferroni correction (E), t-test comparing IL-2::GPI with IL-2::2Ig(F)GPI asVNP (G, H).</p

Differential activation of CD8⁺ T cells by IL-2v decorated VNP.

<p>(<b>A</b>) Flow cytometry analysis of CD69 and TCR expression on P14 TCR transgenic splenocytes. Cells were either left untreated (grey shaded histograms), or stimulated (black line) with IL-2v asVNP or alternatively with αCD3/αCD28 coated microbeads supplemented with 10 or 100 U/ml IL-2 for 18 hours. Percentages of CD69^<b>high</b> and TCR^<b>low</b> cells are shown. (<b>B</b> and <b>C</b>) Flow cytometry analysis of CD25 expression on CD8^<b>+</b> T cells. Purified P14 CD8^<b>+</b> T cells were stimulated for the indicated number of days with IL-2v asVNP, or αCD3/αCD28 coated microbeads supplemented with 10 or 100 U/ml IL-2, as indicated or were left untreated. (<b>B</b>) CD25 expression on CD8^<b>+</b> T cells co-cultured with IL-2v asVNP for three days. Numbers indicate MFI of CD25^<b>+</b> cells. (<b>C</b>) Kinetics of CD25 expression on CD8^<b>+</b> T cells stimulated with indicated asVNP, ansVNP, or αCD3/αCD28 coated microbeads supplemented with 10 or 100 U/ml IL-2. (<b>D</b>) Proliferation of CD8^<b>+</b> T cells upon incubation with IL-2v asVNP, ansVNP, medium or PMA/ionomycin. (<b>E</b>) Absolute numbers of viable P14 CD8^<b>+</b> T cells after 5 days of co-culture with IL-2v asVNP or αCD3/αCD28 coated microbeads supplemented with IL-2. Data are representative (A, B) or show the summary (C-E) of four (except two for αCD3/αCD28) (A), five (except three for ansVNP) (B), at least three (C), nine (except five for ansVNP and two αCD3/αCD28 microbeads) (D) and seven (except four for αCD3/αCD28 microbeads) (E) independent experiments. * p < 0.05, **, p < 0.01, ***, p < 0.001; t-test comparing IL-2::GPI with IL-2::2Ig(F)GPI asVNP (C), Kruskal-Wallis test and Mann-Whitney U-test followed by post hoc Bonferroni correction (D) ANOVA and Tukey’s multiple comparison test (E).</p

Induction of effector functions and memory phenotypes by IL-2v asVNP.

<p>Enhanced <i>in vivo</i> cytotoxicity of CD8^<b>+</b> effector T cells in mice immunized with IL-2::2Ig(F)GPI asVNP. (<b>A</b>) Flow cytometry analysis showing recovery of adoptively transferred and differentially CPD labeled LCMV-GP_33-41 peptide (CPD^<b>dim</b>) or mock peptide (CPD^{<b>bright</b>}) pulsed congenic CD45.1^<b>+</b> splenocytes from CD45.2^<b>+</b> wild-type recipient mice. Two days before target cell transfer, wt mice received 2x10^<b>5</b> purified P14 CD45.1^<b>+</b>CD8^<b>+</b> effector T cells and were immunized with IL-2::GPI or IL-2::2Ig(F)GPI asVNP (black histograms) or with IL-2(A)::GPI or IL-2(A)::2Ig(F)GPI asVNP (open histograms) or were left untreated. (<b>B</b>) Quantification of specific target cell lysis <i>in vivo</i>. Horizontal lines indicate the mean. (<b>C-E</b>) Pre-stimulation of CD8^<b>+</b> T cells with IL-2::GPI asVNP generates higher absolute numbers of memory cells <i>in vivo</i>. P14 CD8^<b>+</b> T cells (CD45.2^<b>+</b>) were <i>in vitro</i> pre-stimulated with IL-2v asVNP or αCD3/αCD28 microbeads (+100 U/ml IL-2) for six days. Equal amounts of viable naïve and activated cells (1x10^<b>6</b>) were adoptively transferred into CD45.1^<b>+</b> congenic recipient mice. After 7 days engraftment of P14 CD8^<b>+</b>CD45.2^<b>+</b> T cells in the inguinal lymphnodes and the spleens were determined by flow cytometry. (<b>C</b>) Flow cytometry analysis showing expression of the indicated markers on naïve (shaded grey histograms) and <i>in vitro</i> pre-activated (black line) CD8^<b>+</b>CD45.2^<b>+</b> donor cells isolated from the lymph nodes of recipient mice. Absolute numbers of CD62L^<b>low</b> and CD62L^<b>high</b> donor cells recovered from (<b>D</b>) inguinal lymphnodes and (<b>E</b>) spleens of recipient mice. Data are representative (A, C) or show the summary (B, D, E) of 28 mice (seven per group) that were analyzed in four independent experiments (A, B), or of 18 mice (eight per group, except for naïve (two), IL-2::GPI (three), αCD3/αCD28 microbeads plus IL-2 (five)) (C-E) that were analyzed in two independent experiments. * p < 0.05, **, p < 0.01 ANOVA, t-test and post hoc Bonferroni correction (B); Mann-Whitney U-test (D, E).</p

Expression and targeting of IL-2 fused to different membrane anchors of CD16b.

<p>(<b>A</b>) Surface expression levels of IL-2 fused to different membrane anchors on HEK-293 cells. HEK-293 producer cells were transfected with indicated plasmids and stained with IL-2-specific (black line) or non-binding control mAb (grey histograms), followed by flow cytometric analysis. Numbers indicate percent positive cells. (<b>B</b>) Percentage of IL-2 positive HEK-293 cells upon transfection with the indicated constructs. (<b>C</b> and <b>D</b>) Expression of IL-2v in HEK-293 producer cells and corresponding VNP preparations as detected with IL-2-specific antiserum. Anti-Gag was used as loading control. Bottom panels show quantification of band intensities (Image J 1.48 software) normalized to values obtained from whole cell lysates of IL-2::GPI transfectants and corresponding VNP. (<b>E</b>) Relative amounts of IL-2 targeted to VNP compared to IL-2::GPI VNP. (<b>F</b>) GPI-anchor attachment targets IL-2 into lipid rafts of HEK-293 cells. Triton X-100 lysates of HEK-293 cells were resolved by 5 to 40% sucrose gradients into nine fractions (top to bottom), subjected to SDS-PAGE, blotted and probed (IB) with IL-2-specific antiserum, CD59 (lipid raft targeting control) and CD147 (non-lipid raft targeting control) mAb. (<b>G</b>) Dot-blot analyses of relative amounts of particles secreted by HEK-293 producer cells transfected with indicated constructs using p30Gag immunoblotting (IB). Data are representative (A, C, D, F) or show the summary (B, E, G) of three (except six for IL-2::GPI and IL-2::1IgGPI) (A to D), four (E, G) and two (F) independent experiments. * p < 0.05, ***, p < 0.001; Kruskal-Wallis test and Mann-Whitney-U-test followed by post hoc Bonferroni correction (B), ANOVA and Tukey’s multiple comparison test (G).</p