Untransfected and SV40-transfected fetal and postnatal XXXX thymic stromal cells. Analysis of phenotype, cytokine gene expression and cytokine production.

@entity1 @entity650 @entity310 @entity2936 @entity6977 @entity1759 @entity7937 @entity1192 @entity379 @entity2280 @entity2071 @entity6826 @entity2841
The thymic stromal network is complex and heterogeneous, containing thymic epithelial cells which are thought to play an important role during T-cell development and thymic fibroblasts which role is less defined. We herein present a phenotypic and functional comparison between defined thymic stromal cell populations. We transfected SV40 ori- into fetal and postnatal thymic stromal cell cultures and obtained SV40-immortalized clones of epithelial and fibroblastic nature as demonstrated by expression of intracellular keratin. These various clones were characterized in detail and compared to their untransfected bulk culture counterparts for phenotype, cytokine gene expression and cytokine production. All the different thymic stromal cells examined, constitutively expressed @entity2071 , @entity7937 , MHC class I antigens, @entity1759 , and the genes coding for @entity6977 , @entity6826 and TGF-beta, but not @entity310 . After @entity1192 stimulation, epithelial cells seemed to produce more @entity2841 than fibroblasts, and that trend was also seen for @entity650 secretion. SV40 cells were also regulated by @entity379 which induced MHC class II antigens and inhibited the @entity1192 induced @entity2841 production. SV40 cells differed from their untransfected counterparts by an atypical expression of @entity2936 and lacked constitutive @entity1192 gene expression. We isolated clones with distinct properties, 24SV48, a highly proliferative @entity2280 positive TEC secreting low levels of @entity2841 and lacking constitutive @entity1192 and beta gene expression, and CT1SV93, an epithelial clone of postnatal origin with a high @entity1192 -induced cytokine production. In spite of differences with untransfected bulk cultures, the various SV40 immortalized clones may represent useful tools to further study the @entity1 thymic stroma.
