Immulectin-2, a Lipopolysaccharide-specific Lectin from an Insect, Manduca sexta, Is Induced in Response to Gram-negative Bacteria *

摘要: A lipopolysaccharide-specific lectin, immulectin-2, was isolated from plasma of the tobacco hornworm,Manduca sexta. Immulectin-2 has specificity for xylose, glucose, lipopolysaccharide, and mannan. cDNA clone encoding immulectin-2 an Escherichia coli-inducedM. sexta larval fat body library. The is 1253 base pairs long, with open reading frame 981 pairs, a 327-residue polypeptide. member C-type lectin superfamily. It consists two carbohydrate recognition domains, which similar to organization M. sextaimmulectin-1. present at constitutively low level in control larvae increased 3–4-fold after injection Gram-negative bacteria or lipopolysaccharide. mRNA detected larvae, its dramatically E. coli. concentration did not change significantly Gram-positive yeast, even though by these treatments. Compared immulectin-1, more restricted binding bacteria. physiological concentrations agglutinatedE. coli calcium-dependent manner. also bound immobilized lipopolysaccharide Binding stimulated phenol oxidase activation plasma. properties are consistent function as pattern receptor detection defense against bacterial infection