Biomedical subjects

P Angelisova

Publications and source records attributed to P Angelisova.

4 recordsLinked to original sources

PubMed2001

Polyunsaturated eicosapentaenoic acid displaces proteins from membrane rafts by altering raft lipid composition.

Polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (20:5 (n-3)) inhibit T lymphocyte activation probably by displacing acylated signaling proteins from membrane lipid rafts. Under physiological conditions, saturated fatty acyl residues of such proteins partition into the cytoplasmic membrane lipid leaflet with high affinity for rafts that are enriched in saturated fatty acyl-containing lipids. However, the biochemical alteration causing displacement of acylated proteins from rafts in PUFA-treated T cells is still under debate but could principally be attributed to altered protein acylation or changes in raft lipid composition. We show that treatment of Jurkat T cells with polyunsaturated eicosapentaenoic acid (20:5 (n-3)) results in marked enrichment of PUFAs (20:5; 22:5) in lipids from isolated rafts. Moreover, PUFAs were significantly incorporated into phosphatidylethanolamine that predominantly resides in the cytoplasmic membrane lipid leaflet. Notably, palmitate-labeled Src family kinase Lck and the linker for activation of T cells (LAT) were both displaced from lipid rafts indicating that acylation by PUFAs is not required for protein displacement from rafts in PUFA-treated T cells. In conclusion, these data provide strong evidence that displacement of acylated proteins from rafts in PUFA-treated T cells is predominantly due to altered raft lipid composition.

Acylation↗

PubMed1999

Cross-linking of membrane CD43 mediates dendritic cell maturation.

CD43/leukosialin is a major sialoglycoprotein of the dendritic cell (DC) surface, which can regulate cell adhesion and has the potential to mediate cell activation signals. Monocyte-derived DC transiently incubated with the anti-CD43 mAb, MEM-59, or with F(ab')2 fragments, but not with monovalent Fab fragments or control IgG, 24 h later showed increased levels of membrane HLA-DR, CD54, CD40, CD80, CD86, and CD83. In parallel, CD43 cross-linking induced synthesis and release of IL-1beta, IL-6, TNF-alpha, IL-12, and IL-10. CD43 ligation inhibited the endocytic activity of DC, and enhanced the capacity of DC to stimulate T cell proliferation in the primary allogeneic and autologous MLR assay. In addition, anti-CD43-treated DC were less efficient at presenting native HIV-1 reverse transcriptase to a specific CD4+ T cell clone, whereas presentation of the reverse transcriptase 55-72 peptide to the same clone was increased. Finally, MEM-59 or its F(ab')2 fragments elicited a rise in intracellular free calcium and tyrosine phosphorylation of a 25-kDa protein in DC. The results thus indicate that CD43 cross-linking with specific ligands induces activation and functional maturation of DC.

Antibodies, Monoclonal↗

PubMed1995

Evidence that CDw108 membrane protein bears the JMH blood group antigen.

BACKGROUND: CDw108 is a cluster-of-differentiation antigen that resides on a glycosylphosphatidylinositol (GPI)-linked protein; it has not previously been shown to be expressed on red cells. JMH is a high-frequency red cell blood group antigen that resides on a GPI-linked protein of molecular weight similar to that bearing CDw108. The purpose of this study was to investigate whether CDw108 is expressed on red cells and whether it resides on the same membrane protein as does JMH. STUDY DESIGN AND METHODS: Murine monoclonal antibodies to CDw108, MEM-121 and MEM-150, as well as a murine monoclonal antibody and human antibodies to JMH were used in radioimmunoassay, inhibition assay, Western blotting, and monoclonal antibody-specific immobilization of erythrocyte antigen assay. RESULTS: MEM-121 and MEM-150 were found to bind to red cells, and MEM-150 blocked binding of human anti-JMH to red cells. Anti-CDw108 and anti-JMH identified red cell membrane proteins that were of similar size and that were absent from JMH-negative red cells on Western blotting. MEM-150 and MEM-121 also immobilized the same protein that reacted with human anti-JMH. CONCLUSION: CDw108 is expressed on red cells and resides on the same GPI-linked membrane protein as does the JMH blood group antigen.

Antibodies, Monoclonal↗

PubMed1992

CD59 molecule: a second ligand for CD2 in T cell adhesion.

The T cell surface molecule CD2 forms, with its counter-receptor CD58 (LFA-3), a powerful adhesion/activation pathway. There is some evidence that CD2 might bind more than a single ligand. Chinese hamster ovary cells (CHO) expressing human CD59 after cDNA transfection (CD59+CHO) form rosettes with human T cells; these rosettes are inhibited in a dose-dependent fashion by the CD59 monoclonal antibody (mAb) H19 and by the CD2 mAb O275 known to block natural rosettes, but not by the CD2R mAb D66, a poor rosette blocker. CD2+CHO transfectants form rosettes with human erythrocytes; these rosettes are inhibited by the CD59 mAb H19 in addition to CD2 mAb O275 and CD58 mAb; murine thymoma cells expressing human CD2 form rosettes with CD59+CHO cells that again are blocked by CD59 H19 and by CD2 O275 mAb. In a marked contrast with H19, two others CD59 mAb, YTH 53.1 and MEM 43, which react with a different epitope on CD59, led to a 50%-70% increase of the number of cells forming rosettes. In addition to rosette experiments, the binding of 125I-labeled CD59 molecules to CD2+CHO cells was specifically inhibited by unlabeled CD59 molecule and CD2 mAb. Furthermore, the binding of CD59 molecules to resting T cells induced expression of CD2R epitopes. These results directly show that CD2 binds CD59 and that subtle molecular changes occur upon binding.

Animals↗