Activation-induced expression of CD1d antigen on mature T cells.
In the present study, we investigated the expression of human CD1d antigen on activated mature T cells. Expression of this glycoprotein was found to be highly regulated and dependent on PHA stimulation. Flow cytometry studies using the NOR3.2 antibody, which recognized CD1d under denaturing conditions, showed a clear increase in its expression after PHA stimulation. Expression of this molecule after PHA activation was confirmed by analysis of its corresponding transcript by RT-PCR. A single band representing mRNA for CD1d membrane isoform was observed in activated PBMC as well as in ER3 CD1D-transfected and MOLT-4, pre-T cell lines, which were used as controls. Western blot analysis revealed an activation-dependent increase in CD1d protein expression when PBMC and enriched T cells were activated for different time periods. Activation-dependent expression of CD1d antigen was also confirmed in allogenic-activated T cells, suggesting that this event could have biological significance. Finally, immunocytochemical studies showed the presence of this protein at the plasma membrane accompanied by a cytoplasmic and perinuclear distribution. Results presented herein provide the first experimental evidence showing that CD1d antigen is present on circulating, activated T lymphocytes, suggesting that its expression is dependent on the activation state of the cells. Elucidation of the molecular mechanisms implicated in the activation-dependent expression of this nonclassical antigen will provide new insights into the understanding of antigen presentation and immune regulation.
Salamone
M C
MC
Division Inmunogenética, Hospital de Clínicas, Facultad de Medicina, Universidad de Buenos Aires, Argentina. marysasinec@is.com.ar
Rabinovich
G A
GA
Mendiguren
A K
AK
Salamone
G V
GV
Fainboim
L
L
D000911:Antibodies, Monoclonal / Q000032:analysis; D018949:Antigens, CD1 / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics / Q000276:immunology; D055610:Antigens, CD1d; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002461:Cell Line, Transformed; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008213:Lymphocyte Activation / Q000235:genetics; D008970:Molecular Weight; D010835:Phytohemagglutinins / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013347:Subcellular Fractions / Q000737:chemistry / Q000276:immunology; D013601:T-Lymphocytes / Q000737:chemistry / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology
D000911:Antibodies, Monoclonal; D018949:Antigens, CD1; D055610:Antigens, CD1d; C526877:CD1D protein, human; D010835:Phytohemagglutinins; D012333:RNA, Messenger