Human allogeneic CD2+ lymphocytes activate airway-derived epithelial cells to produce interleukin-6 and interleukin-8. Possible role for the epithelium in chronic allograft rejection.

BACKGROUND: The adhesion of lymphocytes to the epithelium and the release of proinflammatory cytokines are important features observed during acute and chronic allograft rejection. Development of chronic rejection in lung-transplantation patients is preceded by high levels of interleukin (IL)-6 and IL-8 protein in the bronchoalveolar lavage. Therefore, we studied the expression of IL-6 and IL-8 in cocultures of epithelial cells and allogeneic lymphocytes. METHODS: IL-6 and IL-8 protein levels were determined in supernatants of the airway-derived epithelial cell line A549 and in primary epithelial cells obtained from lung-brushings after coculturing with autologous and allogeneic lymphocytes. Transcriptional mechanisms were detected by transient transfections. RESULTS: Coculture-supernatants of epithelial cells and allogeneic CD2+ lymphocytes show high levels of IL-6 and IL-8 protein due to transcriptional activation of the respective genes in epithelial cells. Highest productions were measured when the epithelial-cell:lymphocyte ratio was 1:10. Highly purified CD4+ and/or CD8+ cells were unable to induce the same response as observed with the total lymphocyte-population. Depletion of CD4+ and/or CD8+ had no effect on the IL-6 and IL-8 production induced by the total CD2+ lymphocyte-population. However, depletion of CD56+ cells diminished the lymphocyte-induced IL-6 and IL-8 production by > 75%. CONCLUSION: These data show that allogeneic CD2+ lymphocytes are able to activate lung-derived epithelial cells, resulting in the release of proinflammatory cytokines, which have a prominent role in chronic allograft rejection observed in lung-transplantation patients.

Cyclosporine, FK506, mycophenolate mofetil, and prednisolone differentially modulate cytokine gene expression in human airway-derived epithelial cells.

BACKGROUND: The immunosuppressive effects of cyclosporine (CsA), tacrolimus (FK506), mycophenolate mofetil (MMF), and prednisolone in cells from the immunological compartment are well documented. In contrast, limited information is available with respect to the effects of these immunosuppressive drugs on airway-epithelial cells, although these cells may contribute to the development of obliterative bronchiolitis (OB) through the production of interleukin (IL)-6 and IL-8. METHODS: We studied the production of IL-6 and IL-8 proteins by airway-derived epithelial cell lines and primary epithelial cell cultures obtained from lung brushings. Transcriptional mechanisms were detected by transient transfections. RESULTS: We demonstrate that CsA dose dependently induces the production of the proinflammatory cytokines IL-6 and IL-8 in both cell lines and primary epithelial cells. FK506 and MMF were also able to upregulate IL-8, although the effect was less dramatic than observed for CsA. Low concentrations of prednisolone (0.01 and 0.001 microg/ml) enhanced IL-6 and IL-8 secretion, whereas concentrations > or =0.01 microg/ml significantly diminished IL-6 secretion. Furthermore, we showed that CsA and prednisolone mediate their effects at the transcriptional level. CONCLUSIONS: The data provide evidence that relevant concentrations of CsA and MMF in vivo may enhance the inflammatory processes in the lower airways of patients after lung transplantation.

Proteases from Aspergillus fumigatus induce interleukin (IL)-6 and IL-8 production in airway epithelial cell lines by transcriptional mechanisms.

Proteases secreted by Aspergillus fumigatus induce the production of cytokines by epithelial cells, including interleukin (IL)-6 and IL-8. In the present study, we focused on the mechanism(s) by which A. fumigatus-derived proteases elicit cytokine production in epithelial cells. In the epithelial cell line A549, IL-6 and IL-8 mRNA levels were enhanced by proteases as a result of transcriptional induction of the respective genes. Transcriptional induction of both genes coincided with enhanced DNA binding of nuclear factor (NF)-kappaB and NF-IL6, whereas activator protein-1 was unlikely to be involved. The enhanced transcriptional activity could be inhibited by the addition of chymostatin, showing serine protease dependency. Posttranscriptional mechanisms affecting the stability of IL-6 and IL-8 mRNAs were not involved in protease-induced IL-6 and IL-8 production. These data show that after exposure to A. fumigatus-derived proteases, IL-6 and IL-8 gene expressions are up-regulated as a result of transcriptional mechanisms.

Prostaglandin E2 differentially modulates IL-5 gene expression in activated human T lymphocytes depending on the costimulatory signal.

BACKGROUND: Protein kinase A (PKA) activation is documented to be inhibitory for T helper cell (T[H1])-like cytokines (IL-2, IFN-gamma), whereas T(H2)-like cytokines (IL-4, IL-5) are not affected or upregulated. We have recently shown that IL-4 gene expression can be inhibited by PKA activation but depends on the mode of T-cell activation. For IL-5 gene expression, we hypothesized that the mode of T-cell activation also determines the ultimate effect of simultaneous PKA activation. OBJECTIVES: The objective of this study was the examination of IL-5 gene expression in healthy T cells activated with various mitogenic stimuli after simultaneous activation of PKA by dibutyryl-cAMP or prostaglandin E2 (PGE2). METHODS: IL-5 mRNA was measured by semiquantitative reverse transcription-polymerase chain reaction or Northern analysis. IL-5 protein was measured by ELISA. Transcriptional mechanisms involved in IL-5 gene expression were determined by nuclear run-on experiments and electrophoretic mobility shift assays. Posttranscriptional mechanisms were determined by actinomycin D chase studies. RESULTS: Anti-CD2-, anti-CD3-, and anti-CD3 plus anti-CD28-induced IL-5 mRNA were completely inhibited by dibutyryl cyclic AMP (10[-3] mol/L) and PGE2 (10[-5] mol/L), whereas concanavalin A-induced IL-5 mRNA was partially reduced. The effect of PGE2 was accomplished at the transcriptional level, probably as the result of inhibition of DNA binding of nuclear factor-kappaB. Anti-CD3 plus anti-CD28-induced IL-5 protein (504 +/- 56 pg/ml) was significantly reduced by PGE2 (122 +/- 42 pg/ml, p < 0.001). Addition of cytokines that use the IL-2 receptor gamma(C) chain (IL-2, IL-7, IL-15) abrogated the PGE2-induced inhibition of IL-5 protein. In contrast, concanavalin A plus PMA-induced IL-5 protein (75 +/- 8 pg/ml) was significantly upregulated by the simultaneous addition of PGE2 (128 +/- 17 pg/ml, p < 0.03). CONCLUSIONS: PKA activation differentially modulates IL-5 gene expression and depends on the mode of T-cell activation.