Major histocompatibility class I molecules present Urtica dioica agglutinin, a superantigen of vegetal origin, to T lymphocytes.
The Urtica dioica agglutinin (UDA) shares with the superantigens the property of activating T cell subsets bearing particular Vbeta segments of the TCR. However, UDA is a lectin capable of binding to many glycoproteins on cell membranes. The implication of MHC versus other glycoproteins in UDA presentation was presently studied. Using mutant mice lacking MHC class I (MHC-I), MHC class II (MHC-II) or both MHC antigens, we provided evidence that MHC-I and MHC-II molecules serve as UDA receptors. Presentation by either one of these molecules ensured similar T cell responses and co-stimulatory signals were mandatory for optimal T cell activation and proliferation both in MHC-I and MHC-II contexts. Remarkably, in the absence of MHC molecules, UDA could not be efficiently presented to T cells by other glycosylated proteins. Surface plasmon resonance studies were used to confirm the binding of UDA to MHC-I molecules using a fusion protein consisting of MHC-I domains and beta2-microglobulin. The results indicated that the interaction between UDA and MHC-I molecules implicated lectin-binding site(s) of UDA. Taken together, our data demonstrate that, in addition to MHC-II antigens, MHC-I molecules serve as an alternative ligand for UDA.
Rovira
P
P
Unité d'Immunophysiologie Moléculaire, Institut Pasteur, Paris, France.
Buckle
M
M
Abastado
J P
JP
Peumans
W J
WJ
Truffa-Bachi
P
P
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D002455:Cell Division; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D037102:Lectins / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D037121:Plant Lectins; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D015398:Signal Transduction; D012995:Solubility; D018089:Superantigens / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D037102:Lectins; D037121:Plant Lectins; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens; C048862:stinging nettle lectin