Adhesion molecules involved in the binding and subsequent engulfment of thymocytes by a rat thymic epithelial cell line.
A rat thymic epithelial cell (TEC) line (R-TNC.1) was established from a long-term TEC culture. Based on its ultrastructure, phenotype and cytokeratin profile, this line was characterized as a type of cortical TEC. R-TNC.1 cells had nursing activity which was manifested by the binding and subsequent engulfment of thymocytes. The role of adhesion molecules involved in these processes was studied extensively using a coculture of resting thymocytes and unstimulated or interferon-gamma (IFN-gamma)-stimulated R-TNC.1 cells. It was found that a number of adhesion molecules, such as CD2, CD4, CD8, LFA-1, CD18, ICAM-1 and Thy-1, was partly involved in the nursing activity. The effect of monoclonal antibodies (mAb) to these molecules depended on the incubation time and stimulation of R-TNC.1 cells. The inhibitory effect of mAb to CD2, LFA-1, CD18 and ICAM-1 on thymocyte engulfment was higher than their effect on thymocyte binding to the R-TNC.1 line. In addition, a LFA-1/CD18-dependent/ICAM-1-independent adhesion pathway was identified when unstimulated R-TNC.1 cells with minimal expression of ICAM-1 were used. The combination of inhibitory mAb did not completely abrogate the nursing activity of the R-TNC.1 line, suggesting the possible involvement of some other adhesion molecules.
Institute of Medical Research, Military Medical Academy, Belgrade.
M
M
Colić
D
D
Vucević
M
M
Miyasaka
T
T
Tamatani
M D
MD
Pavlović
A
A
Dujić
D000818:Animals; D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002460:Cell Line; D004848:Epithelium / Q000378:metabolism / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D008854:Microscopy, Electron; D010641:Phenotype; D051381:Rats; D011919:Rats, Inbred Strains; D013950:Thymus Gland / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules