Characterization of human thymic epithelial cell surface antigens: Phenotypic similarity of thymic epithelial cells to epidermal keratinocytes

1995 ◽  
Vol 15 (2) ◽  
pp. 80-92 ◽  
Author(s):  
Dhavalkumar D. Patel ◽  
Leona P. Whichard ◽  
Gilbert Radcliff ◽  
Stephen M. Denning ◽  
Barton F. Haynes
Author(s):  
Marleen H. van Coevorden-Hameete ◽  
Maarten J. Titulaer ◽  
Marco W. J. Schreurs ◽  
Esther de Graaff ◽  
Peter A. E. Sillevis Smitt ◽  
...  

2003 ◽  
Vol 285 (5) ◽  
pp. C1304-C1313 ◽  
Author(s):  
O. K. Nihei ◽  
A. C. Campos de Carvalho ◽  
D. C. Spray ◽  
W. Savino ◽  
L. A. Alves

We here describe intercellular calcium waves as a novel form of cellular communication among thymic epithelial cells. We first characterized the mechanical induction of intercellular calcium waves in different thymic epithelial cell preparations: cortical 1-4C18 and medullary 3-10 thymic epithelial cell lines and primary cultures of thymic “nurse” cells. All thymic epithelial preparations responded with intercellular calcium wave propagation after mechanical stimulation. In general, the propagation efficacy of intercellular calcium waves in these cells was high, reaching 80-100% of the cells within a given confocal microscopic field, with a mean velocity of 6-10 μm/s and mean amplitude of 1.4- to 1.7-fold the basal calcium level. As evaluated by heptanol and suramin treatment, our results suggest the participation of both gap junctions and P2 receptors in the propagation of intercellular calcium waves in thymic nurse cells and the more prominent participation of gap junctions in thymic epithelial cell lines. Finally, in cocultures, the transmission of intercellular calcium wave was not observed between the mechanically stimulated thymic epithelial cell and adherent thymocytes, suggesting that intercellular calcium wave propagation is limited to thymic epithelial cells and does not affect the neighboring thymocytes. In conclusion, these data describe for the first time intercellular calcium waves in thymic epithelial cells and the participation of both gap junctions and P2 receptors in their propagation.


1998 ◽  
Vol 46 (5) ◽  
pp. 661-668 ◽  
Author(s):  
Alfredo Martínez ◽  
Andrew Farr ◽  
Michele D. Vos ◽  
Frank Cuttitta ◽  
Anthony M. Treston

C-terminal amidation is a post-translational processing step necessary to convey biological activity to a large number of regulatory peptides. In this study we have demonstrated that the peptidyl-glycine α-amidating monooxygenase enzyme complex (PAM) responsible for this activity is located in the medullary stellate epithelial cells of the thymus and in cultured epithelial cells bearing a medullary phenotype, using Northern blot, immunocytochemistry, in situ hybridization, and enzyme assays. Immunocytochemical localization revealed a granular pattern in the cytoplasm of the stellate cells, which were also positive for cytokeratins and a B-lymphocyte-associated antigen. The presence of PAM activity in medium conditioned by thymic epithelial cell lines suggests that PAM is a secreted product of these cells. Among the four epithelial cell lines examined, there was a direct correlation between PAM activity and content of oxytocin, an amidated peptide. Taken together, these data provide convincing evidence that thymic epithelial cells have the capacity to generate amidated peptides that may influence T-cell differentiation and suggest that the amidating enzymes could play an important role in the regulation of thymic physiology.


1985 ◽  
Vol 33 (7) ◽  
pp. 687-694 ◽  
Author(s):  
J F Nicolas ◽  
W Savino ◽  
A Reano ◽  
J Viac ◽  
J Brochier ◽  
...  

The mouse thymic epithelial network was studied using three different anti-keratin antibodies. One of these antibodies, KL1, exclusively recognized a small subset of medullary epithelial cells characterized by its content of a high molecular weight keratin (63 kD). Since epithelial differentiation is known to be associated with the acquisition of high molecular weight keratins, KL1-positive cells, which express the Ia antigen and secrete thymulin, may represent a subset of highly differentiated cells among mouse thymic epithelial cells (TEC). These data reflect the heterogeneity of the thymic epithelium and support the concept that distinct TEC subsets might provide the thymus with different microenvironments.


1988 ◽  
Vol 34 (6) ◽  
pp. 757-766 ◽  
Author(s):  
Jan M. De Boer ◽  
Friso H. F. Plantema

From patients with bacterial vaginosis motile, anaerobic, comma-shaped bacteria can be isolated, which have recently been placed into the new genus Mobiluncus. In this study, electron microscopy was used to examine the in situ adherence of these motile curved rods to detached epithelial cells (comma cells) in vaginal fluid from two patients with bacterial vaginosis. Thin sections showed that the curved rods attached both directly to the epithelial cell surface and at various distances from it. It is concluded that after initial attachment these motile bacteria can grow at the epithelial cell surface in sessile microcolonies. Ruthenium red staining demonstrated a coating of precipitated glycocalyx material both on the surface of the curved rods and on their flagella. This may indicate that in situ the adherent curved rods were enclosed in a very hydrated matrix of exopolysaccharides. Conspicuous was the ability of the curved rods to attach to the epithelial cell surface via their cell tips. However, in situ no specialized bacterial cell surface structures were seen that might explain this polar attachment. Electron microscopy of pure cultures demonstrated that both Mobiluncus curtisii subsp. curtisii and Mobiluncus mulieris can produce a glycocalyx in vitro.


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