Interferon gamma alters the phenotype of rat thymic epithelial cells in culture and increases interleukin-6 production.

Miodrag Colic,Nada Pejnovic,Sonja Gašic,Milena Kataranovski,Ljiljana Popovic,Aleksandar Dujic

doi:10.1155/1992/60719

Miodrag Colic, Nada Pejnovic + Show 4 more

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https://doi.org/10.1155/1992/60719

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Journal: Developmental Immunology	Publication Date: Jan 1, 1992
Citations: 11	License type: CC BY 3.0

Affiliation: Military Medical Academy

Abstract

Rat thymic epithelial cells (TEC) in long-term culture were characterized by anticytokeratin monoclonal antibodies (mAbs) and electron microscopy. Phenotypic analysis performed by a large panel of mAbs showed that the highest percentage of these cells was of the subcapsular/medullary type. Recombinant rat interferon (IFN)-gamma up-regulated class-I and class-II MHC expression by TEC in culture as confirmed by immunohistochemistry and flow cytometry, but did not significantly alter other cell markers. TEC supernatants of IFN-gamma- treated cultures showed higher interleukin-6 (IL-6) activity, compared to the control, as determined by proliferation of the IL-6-sensitive B9-cell line. Increased IL-6 activity was probably not a consequence of increased TEC number in IFN-gammatreated cultures because IFN did not significantly stimulate TEC proliferation in vitro. In contrast, IL-6 significantly stimulated TEC proliferation, indicating that this cytokine is not only a regulatory molecule for T-cell proliferation, but could also be an autocrine growth factor for thymic epithelium.

Highlights

The importance of the thymic microenvironment, which is composed of epithelial cells, macrophage/dendritic cells, and fibrous stroma (Lobach and Haynes, 1988; van Ewijk, 1988), in T-cell development has been well established (Lobach and Haynes, 1988; Sprent et al, 1988).the role of individual components in thymocyte positioning, differentiation, and proliferation as well as development of a self-MHC restricted T-cell repertoire has not been fully elucidated
We succeeded in successfully cultivating pure rat thymic epithelial cells (TEC) population using RPMI-1640 medium with addition of 15% fetal calf serum (FCS), insulin, dexamethasone, epidermal growth factor (EGF) and poly-L-lysine (PLL) as an adhesive matrix
One long-term culture passaged for more than 8 months was used in these experiments to study the effect of recombinant rat interferon (INF)-gamma on the phenotype and cytokine production by TEC

Summary

INTRODUCTION

The importance of the thymic microenvironment, which is composed of epithelial cells, macrophage/dendritic cells, and fibrous stroma (Lobach and Haynes, 1988; van Ewijk, 1988), in T-cell development has been well established (Lobach and Haynes, 1988; Sprent et al, 1988). In order to study the relationship between thymic-microenvironmental cells and thymocytes, several investigators have used a more direct approach involving in vitro cell culture assays. Many difficulties in maintaining pure populations, especially thymic epithelial cells (TEC) were reported We succeeded in successfully cultivating pure rat TEC population using RPMI-1640 medium with addition of 15% fetal calf serum (FCS), insulin, dexamethasone, epidermal growth factor (EGF) and poly-L-lysine (PLL) as an adhesive matrix. One long-term culture passaged for more than 8 months was used in these experiments to study the effect of recombinant rat interferon (INF)-gamma on the phenotype and cytokine production by TEC. It is the first report showing that INF-gamma stimulates IL-6 production by thymic epithelium in vitro

RESULTS

DISCUSSION

MATERIALS AND METHODS

Bioassay for IL-6