Correlated expression of surface antigens in human thymocytes. Evidence of class I HLA modulation in thymic maturation.
The correlated expression of several surface antigens (CD 1, class I HLA, CD3) was examined in human unfractionated thymocytes or selected subsets by using single or double-color flow cytometry. Prethymocyte subpopulations expressed high levels of HLA. A high proportion of cortical cells expressed low levels of either HLA or CD 3 antigens. Most of these HLA+ cortical cells corresponded to the more immature cells and did not express HLA-B loci products. CD 1 a and CD 3 antigens were expressed in a high percentage of cells and the levels of expression of each antigen in individual cells were inversely correlated. These data and the contour of double-color histograms are suggestive of the existence of a single pathway of thymocyte differentiation in which class I HLA expression is switched off around the time of the initiation of CD 3 (and Ti?) expression. We suggest that the anti-major histocompatibility complex (MHC) specificity of the unselected Ti receptor may be incompatible with the expression of MHC products on the cell membrane. At this stage, CD 1 antigens, whose expression is inversely correlated with that of HLA, may fulfill the role of MHC antigens. The latter can be re-expressed later on, once the anti-MHC specificities of the Ti receptors have been selected against. Studies on in vitro modulation of HLA molecules by interferon-alpha did not reveal any correlation to the expression of CD 1 or CD 3 antigens.
Gambon
F
F
Servicio de Immunología, Clínica Puerta de Hierro, Madrid, Spain.
Kreisler
M
M
Díaz-Espada
F
F
D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis*; D002454:Cell Differentiation; D002478:Cells, Cultured; D002675:Child, Preschool; D006680:HLA Antigens / Q000032:analysis / Q000276:immunology*; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D015236:HLA-C Antigens; D006801:Humans; D008213:Lymphocyte Activation; D010641:Phenotype; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology / Q000502:physiology*; D013950:Thymus Gland / Q000254:growth & development
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D006680:HLA Antigens; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D015236:HLA-C Antigens