Immunosuppressive activity of Tamm-Horsfall glycoprotein oligosaccharides: effect of removal of outer sugars and conjugation with a protein carrier.
Tamm-Horsfall (TH) glycoprotein, the major protein of human urine, is, in vitro, a powerful immunosuppressive agent and the activity resides in its oligosaccharide chains. In this study we investigated structural features required for the inhibitory activity of TH glycoprotein oligosaccharides in the one-way mixed lymphocyte reaction (MLR). We found that both high-mannose and complex-type TH glycopeptides, fractionated from Pronase-digested TH glycoprotein, behaved as inhibitors. Sequential exoglycosidase digestion of complex-type TH glycopeptide results in a slight increase of the inhibitory activity, with a maximum after desialylation and beta-galactosidase treatment. These results suggest that the immunosuppressive activity resides in the central portion of TH glycoprotein N-linked oligosaccharides. The conjugation of complex-type TH glycopeptides to a protein carrier, such as bovine serum albumin, greatly enhanced the inhibitory activity. This effect occurred if the TH-glycopeptide conjugate was added to MLR within the first 24 hr. These results indicate that (i) the immunosuppressive activity is strongly dependent on a multivalent interaction between TH oligosaccharides and ligand(s) at the lymphocyte surface; (ii) an early step of cell-cell recognition is the target of the immunosuppressive conjugate; (iii) TH oligosaccharides compete with a carbohydrate recognition system between effector and stimulator cells which contributes to the MLR-induced blastogenesis.
Dall'Olio
F
F
Dipartimento di Patologia Sperimentale dell'Università di Bologna, Italy.
Chiricolo
M
M
Malagolini
N
N
Franceschi
C
C
Serafini-Cessi
F
F
D002240:Carbohydrate Sequence; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D005779:Immunodiffusion; D007165:Immunosuppression Therapy; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008969:Molecular Sequence Data; D009088:Mucoproteins / Q000276:immunology*; D009844:Oligosaccharides / Q000737:chemistry / Q000276:immunology*; D012795:Sialoglycoproteins / Q000276:immunology; D012995:Solubility; D013329:Structure-Activity Relationship; D013997:Time Factors; D058949:Uromodulin
D009088:Mucoproteins; D009844:Oligosaccharides; D012795:Sialoglycoproteins; C548612:UMOD protein, human; D058949:Uromodulin