Binds lactose. May play a role in fruiting body formation. Displays toxicity towards the nematode C.elegans by binding to a specific Gal-beta-1,4-Fuc-alpha-1,6 modification of N-glycan cores on C.elegans intestinal cells. Homotetramer. Oligomerization is required for carbohydrate binding. Detected in extracellular matrix, cell wall and cytoplasmic membrane-bound bodies.