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A human T-cell receptor recognizes 'O' - linked sugars from the hinge region of human IgA1 and IgD.
- Source :
- Immunology; Sep94, Vol. 83 Issue 1, p99-106, 8p
- Publication Year :
- 1994
-
Abstract
- A receptor which binds secretory lgA (sIgA) is expressed on human T cells from patients with systemic lupus erythematosus, rheumatoid arthritis, Behcet's syndrome and IgA nephropathy and on normal T cells following phytohaemagglutinin (PHA) stimulation. The specificity of this receptor was initially probed with a panel of normal serum immunoglobulins in competitive inhibition assays with sIgA using two-colour immunofluorescence. While the receptor showed the strongest affinity for igAl (IC<subscript>50</subscript>10<superscript>-6</superscript> M), IgD which has a similarly glycosylated hinge region to IgAl, also bound to the receptor (IC<subscript>50</subscript> 10<superscript>-5</superscript> M). IgA2, which lacks the 'O'-glycosylated hinge region, did not significantly inhibit the binding at these concentrations suggesting that the IgA determinants for this receptor might be the oligosaccharides present in the hinge region of IgAl. IgAl has up to 10 'O'-linked oligosaccharides and four N-linked oligosaccharides per molecule. In order to probe the role of the 'O'-linked hinge sugars in the binding event, a sugar library was prepared from IgAl by a procedure designed to release 'O'-linked oligosaccharides preferentially, and to retain them in the natural closed ring formation. The sugars were released by hydrazinolysis at 65° and the resulting oligosaccharide library analysed by high voltage paper electrophoresis (HVE) and P4 gel permeation chromatography. Competitive inhibition studies demonstrated that both the library and the individual 'O'-linked sugars associated with IgA1 were implicated in the binding of IgAl to this receptor (IC<subscript>50</subscript> between 1 × 10<superscript>-5</superscript> M and 6 × 10<superscript>-s</superscript> M). Within this range the individual sugars showed small differences in their affinity for the receptor in the following order: Galβ3GalNAc = NeuNAc2α3(6)Galβ3GalNAc > NeuNAc2α3(6)Galβ3[NeuNAc2α6]GalNAc ≥ GalNAc. [ABSTRACT FROM AUTHOR]
- Subjects :
- T cells
LYMPHOCYTES
SUGARS
CARBOHYDRATES
IMMUNOGLOBULINS
GLOBULINS
Subjects
Details
- Language :
- English
- ISSN :
- 00192805
- Volume :
- 83
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Immunology
- Publication Type :
- Academic Journal
- Accession number :
- 13373380