Galanthus nivalis lectin or agglutinin (GNL/GNA) is isolated from snowdrop bulbs. GNL consists of four identical subunits with a molecular weight of 50,000 and an isoelectric point between pH 3.5 and pH 4.0. Galanthus nivalis lectin, unlike most mannose-specific lectins, is not a metalloprotein and does not require Ca++or Mn++ for binding.

This lectin is known to agglutinate rabbit erythrocytes but not human erythrocytes. GNL contains little to no carbohydrate and specifically binds to murine IgM immunoglobin and human beta2-macroglobulin, but not to alpha-linked glucose (unlike majority of mannose-binding lectins). Structures containing (beta-1,3) mannose residues are preferred for binding and elutes with the sugar Mannose. GNL is useful for HIV research, applicable for blood cell agglutination studies, and has set a model system to help understand the molecular basis of how proteins recognize carbohydrates.