Agglutination Activity of Fasciola gigantica DM9-1, a Mannose-Binding Lectin

Abstract

The DM9 domain is a protein unit of 60-75 amino acids that has been first detected in the fruit fly <i>Drosophila</i> as a repeated motif of unknown function. Recent research on proteins carrying DM9 domains in the mosquito <i>Anopheles gambiae</i> and the oyster <i>Crassostrea gigas</i> indicated an association with the uptake of microbial organisms. Likewise, in the trematode <i>Fasciola gigantica</i> DM9-1 showed intracellular relocalization following microbial, heat and drug stress. In the present research, we show that FgDM9-1 is a lectin with a novel mannose-binding site that has been recently described for the protein CGL1 of <i>Crassostrea gigas</i>. This property allowed FgDM9-1 to agglutinate gram-positive and -negative bacteria with appropriate cell surface glycosylation patterns. Furthermore, FgDM9-1 caused hemagglutination across all ABO blood group phenotypes. It is speculated that the parenchymal located FgDM9-1 has a role in cellular processes that involve the transport of mannose-carrying molecules in the parenchymal cells of the parasite.