Urtica dioica agglutinin (UDA) (UDA)

Urtica dioica agglutinin (UDA) is a small, monomeric lectin (approximately 8.5 kDa) isolated from the rhizomes of the stinging nettle plant (UniProt P11218). It is distinguished by its unique ability to function as a carbohydrate-dependent superantigen, binding specifically to N-acetylglucosamine (GlcNAc) oligomers on the glycans of the T-cell receptor (TCR) and Major Histocompatibility Complex (MHC) class II molecules (PMID: 1314133, 7505035). This binding cross-links the TCR and MHC II, triggering the activation and proliferation of specific T-cell subsets, particularly those expressing certain Vβ chains (PMID: 8432977). Beyond its immunomodulatory properties, UDA has demonstrated significant antiviral activity against various enveloped viruses, including HIV and coronaviruses, by binding to the glycans on viral envelope glycoproteins and preventing viral entry into host cells (PMID: 15110964, 32405135). Due to its ability to modulate immune responses and block viral infections, UDA is a subject of research for treating autoimmune conditions and viral outbreaks. However, its potential to induce massive cytokine release and its nature as a foreign plant protein present challenges for clinical development (PMID: 11069066).

Other names

Nettle lectinStinging nettle agglutininUrtica dioica lectinUDA

UDA acts as a molecular bridge by binding to N-acetylglucosamine (GlcNAc) residues on the glycans of both the T-cell receptor (TCR) and MHC class II molecules, bypassing traditional peptide-MHC recognition to induce T-cell activation (PMID: 1314133, 7505035). It also inhibits viral entry by binding to glycans on viral envelope proteins (PMID: 15110964).