DR. D'ADAMO: LECSTER 7

The lectin database of Dr. Peter D'Adamo.
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Urtica dioica
SPECIES IMAGE
SOURCE	Stinging nettle root
LECTINS	UDA
MOLECULAR IMAGE
CLASS	Chitin-binding lectins
NOMEN	LECp.Urt.Dio.rh.Hch1
INDEX	Plant lectin / Plant / Rhizome / Hololectins / GlcNAc/(GlcNAc)-binding lectins
CHARACTERIZATION	UDA can be a valuable tool for the anlysis of themechanisms involved in T-cell activation and proliferation. See: Res. Immunol. 1995 (146); 249-262 UDA exhibits antifungal properties. It inhibits growth of phytopathogenic and saprophytic chitin-cotnaining fungi ( Botyrus cinerea, Trichderma viride, T. hamatum, Phycoimyces blaksleeanus, Phoma betae, Collectotrichum lindemuthianum and Septoria nodorum). The antifungal activity of UDA differs from that of chitinases. Moreover, UDA acts synergistically with chitinase in inhibiting fungal growth. See: Science 1989 (245); 1100-1102 UDA shows antiviral activity, inhibiting HIV-1, HIV-2, CMV-, RSV- and influenza A virus induced cytpathology at a 50% effective concentration ranging from 0.3 to 9 �m/ml. See: Antiviral Res. 1992 (18); 191-207 Purified UDA is a very stable protein. It is not denatured by acid and withstands heating at 80� C for 15 minutes, and even heating in a boiling water bath for 15 minutes; 50& of the initial agglutination activity is retained. See: FEBS Letters 1984 (177) 99-103
BIOACTIVITY	According to one source UDA is not blood group specific, but another claims that it agglutinates group B erythrocytes. See: FEBS Letters 1984 (177); 99-103 Its ability to aggutinate rabbit erythrocytes, however, is unquestioned. The lectin behaves as a superantigen for murine T cells, inducing the exclusive proliferation of Vbeta8.3(+) lymphocytes. UDA is unique among known T cell superantigens because it can be presented by major histocompatibility complex (MHC) molecules of both class I and II. UDA induces the proliferation of mouse T-lymphocytes. See: Res. Immunol. 1995 (146); 249-262 It differs from the traditional mitogens in that the UDA-induced activation of murine T-cells is characterized by late kinetics of proliferation and by the fact that only a limited portion of the CD+4 and CD+8 T-lymphocytes enter into the cell cycle. Therefore UDA is regarded as a superantigen although it does not possess the toxicity of the exogenous superantigens. Similar to the other superantigens, the clonal expression of T-cells is followed by the deletion of the majority of these lymphocytes by apoptosis whereas the remaining Tcells become anergic to UDA restimulation. In contrast to other superantigens the clonal expansion of the T-cells does not occur in the thymus, but only in the spleen and lymph nodes. See: Res. Immunol. 1995 (146); 249-262 UDA induces the production of interferon (HuFN gamma) in fresh human lymphocytes. See: FEBS Letters 1984 (177); 99-103 Incorporation of nettle lectin into the diet of rats reduces the apparent digestibility and utilization of dietary proteins and the growth of rats. UDA acts as a modest growth factor for the gut, although its effects are relatively modest.
SOURCE TISSUE	Rhizome
SPECIFICITY	GlcNAc (oligomers).Urtica dioica agglutinin (UDA) saccharides containing N-acetylglucosamine (GlcNAc). UDA also binds to glycans on the T cell receptor (TCR).
INHIBITORS
REFERENCES	Plant Mol Biol 1999 Jan;39(2):335-47 Fold Des 2000 Jun 15;8(6):593-603

DR. D'ADAMO: LECSTER 7

Urtica dioica