Expression of CD1 and class I MHC antigens by human thymocytes.
The acquisition of surface class I MHC molecules is associated with the maturation of thymocytes. Here, surface expression of class I MHC and CD1, which represents a family of MHC-related molecules, was analyzed on various human immature and mature thymocyte subpopulations. Class I expression was inversely related to the expression of CD1. The majority of CD4+ CD8+ cortical type thymocytes expressed low levels of class I MHC Ag, the previously described CD4+ CD8+ thymocyte subpopulation with low CD8 expression exhibited intermediate levels of class I MHC, whereas most of the single positive CD4 and CD8 thymocytes displayed high levels of class I MHC. Biochemical comparison of CD1 and class I showed that thymic class I molecules were post-translationally modified by phosphorylation, whereas CD1 was not phosphorylated. Furthermore, our studies suggested that in addition to CD1/CD8 complexes, thymocytes bear CD8/class I complexes. Chemical cross-linking and peptide mapping studies clearly identified the CD8-associated protein on thymic clones as the class I MHC molecule.
Blue
M L
ML
Division of Tumor Immunology, Dana Farber Cancer Institute, Boston, MA.
Levine
H
H
Daley
J F
JF
Branton
K R
KR
Schlossman
S F
SF
D018949:Antigens, CD1; D000943:Antigens, Differentiation / Q000032:analysis* / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D017252:CD3 Complex; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D006801:Humans; D010766:Phosphorylation; D011233:Precipitin Tests; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
D018949:Antigens, CD1; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I; D011948:Receptors, Antigen, T-Cell