Activation-induced expression of CD1d antigen on mature T cells

• Published in: Journal of leukocyte biology Vol. 69; no. 2; pp. 207 - 214
• Main Authors: C. Salamone, María, Rabinovich, Gabriel A., Mendiguren, Ana K., Salamone, Gabriela V., Fainboim, Leonardo
• Format: Journal Article
• Language: English
• Published: United States Society for Leukocyte Biology 01-02-2001
• Subjects: activated PBMC; Antibodies, Monoclonal - analysis; Antigens, CD1 - biosynthesis; Antigens, CD1 - blood; Antigens, CD1 - genetics; Antigens, CD1 - immunology; Antigens, CD1d; Blotting, Western; CD1d antigen; CD1d isotope; Cell Differentiation - genetics; Cell Differentiation - immunology; Cell Line, Transformed; Flow Cytometry; Humans; Immunohistochemistry; Lymphocyte Activation - genetics; Molecular Weight; phytohemagglutinin; Phytohemagglutinins - pharmacology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - biosynthesis; Subcellular Fractions - chemistry; Subcellular Fractions - immunology; T-Lymphocytes - chemistry; T-Lymphocytes - cytology; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; Transfection; Tumor Cells, Cultured; Up-Regulation - genetics; Up-Regulation - immunology
• ISSN: 0741-5400; 1938-3673
• DOI: 10.1189/jlb.69.2.207

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.