Selection of CD4+CD8+ thymocytes by complex formation with medulla-derived epithelial cells.
The role of lymphostromal complexes in T-cell differentiation is far from elucidated, mainly because a clear association of a particular stromal cell type with a distinct thymocyte subset has never been identified. Using an in vitro system, detecting the adherence of thymocytes to a thymic medullary epithelial cell line (E-5), we showed that the phenotype of these thymocytes was that of cortical type: Thy-1hi, LFA-1+, PNAhi, CD4+CD8+, MEL-14-/lo, IL-2R-, CD3-/lo, and TcR V beta 8-/lo. They were enriched in cells in G2/M at the time of complex formation, showed a higher basal proliferation in culture, and did not respond to PHA, IL-2 and only marginally to Con A. These data show that complex formation with mouse thymic medullary epithelium selects for CD4+CD8+ thymocytes, as shown by the marked decrease in CD4+CD8-/CD4-CD8+ thymocytes, and the incapacity of CD4-CD8- thymocytes to adhere.
Hugo
P
P
Institut Armand Frappier, Laval, Quebec, Canada.
Potworowski
E F
EF
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D015704:CD4 Antigens / Q000032:analysis*; D016827:CD8 Antigens; D002448:Cell Adhesion; D004848:Epithelium / Q000276:immunology; D007399:Interphase; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D010641:Phenotype; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D016827:CD8 Antigens