Lectins

Ricin ( ) is a lectin (a carbohydrate-binding protein) and a highly potent toxin produced in the seeds of the castor oil plant, Ricinus communis. The median lethal dose (LD50) of ricin for mice is around 22 micrograms per kilogram of body mass via intraperitoneal injection. Oral exposure to ricin is far less toxic. An estimated lethal oral dose in humans is approximately one milligram per kilogram of body mass.

thumb|A typical legume lectin monomer (lentil lectin), complexed with a sugar ([[glucose). The four sugar-binding loops are shown in different colours. The variable loop that confers monosaccharide specificity is shown in orange.]]

The selectins (cluster of differentiation 62 or CD62) are a family of cell adhesion molecules (or CAMs). All selectins are single-chain transmembrane glycoproteins that share similar properties to C-type lectins due to a related amino terminus and calcium-dependent binding. Selectins bind to sugar moieties and so are considered to be a type of lectin, cell adhesion proteins that bind sugar polymers.

Abrin is an extremely toxic toxalbumin found in the seeds of the rosary pea (or jequirity pea), Abrus precatorius. It has a median lethal dose of 0.7 micrograms per kilogram of body mass when given to mice intravenously (approximately 3.86 times more toxic than ricin, being 2.7 micrograms per kilogram). The median toxic dose for humans ranges from 10 to 1000 micrograms per kilogram when ingested and is 3.3 micrograms per kilogram when inhaled.

mammalian protein found in Homo sapiens

Phytohaemagglutinin (PHA, or phytohemagglutinin) is a lectin found in plants, especially certain legumes. PHA actually consists of two closely related proteins, called leucoagglutinin (PHA-L) and PHA-E. These proteins cause blood cells to clump together. PHA-E cause erythrocytes (red blood cells) to clump. PHA-L causes leukocytes (white blood cells) to clump. Phytohaemagglutinin has carbohydrate-binding specificity for a complex oligosaccharide containing galactose, N-acetylglucosamine, and mannose.

a lectin (carbohydrate-binding protein) originally extracted from the jack-bean

CD33 or Siglec-3 (sialic acid binding Ig-like lectin 3, SIGLEC3, SIGLEC-3, gp67, p67) is a transmembrane receptor expressed on cells of myeloid lineage. It is usually considered myeloid-specific, but it can also be found on some lymphoid cells.

CD22, or cluster of differentiation-22, is a molecule belonging to the SIGLEC family of lectins. It is found on the surface of mature B cells and to a lesser extent on some immature B cells. Generally speaking, CD22 is a regulatory molecule that prevents the overactivation of the immune system and the development of autoimmune diseases.

Collectins, col-lectins, (collagen-containing C-type lectins) are a part of the innate immune system. They form a sub-family of collagenous Ca2+-dependent lectins of the family of C-type lectins, which are found in animals. Collectins are soluble pattern recognition receptors (PRRs). Their function is to bind to oligosaccharide structure or lipids that are on the surface of microorganisms. Like other PRRs they bind pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) of oligosaccharide origin. Binding of collectins to microorganisms may trigger elimin

Galectin-3 is a protein that in humans is encoded by the LGALS3 gene. Galectin-3 is a member of the lectin family, of which 14 mammalian galectins have been identified.

Ficolins are pattern recognition receptors that bind to acetyl groups present in the carbohydrates of bacterial surfaces and mediate activation of the lectin pathway of the complement cascade.

protein-coding gene in the species Homo sapiens