Lectin specific for terminal, non-reducing N-acetylgalactosamine (Gal-NAc)-containing carbohydrates including N,N'-diacetyllactosediamine/LDN (GalNAcbeta1-4GlcNAc, LacdiNAc). Specific also for carbohydrates containing N-acetylglucosamine (-GlcNAc) or N-acetyllactosamine (-Galbeta1-4GlcNAc) at the reducing end. Agglutinates human blood group A, AB, B and O erythrocytes with a strong preference for group A. Agglutinates bovine erythrocytes with a very low specificity (PubMed:19100814, PubMed:22298779). Binds carbohydrates bivalently, which is required for its biological activity (PubMed:22298779). Exhibits insecticidal activity against the fruit fly D.melanogaster, mosquito A.aegypti, and amoebozoa A.castellanii. Has anti-nutritional activity against Colorado potato beetle L.decemlineata, and against worm C.elegans (PubMed:21556921, PubMed:21486374). Has antiproliferative activity against human leukemic T-cells (PubMed:19100814). Has an immunostimulatory effect on human antigen-presenting dendritic cells, which are subsequently able to induce efficient T-cell immune responses (PubMed:22044067). Optimum pH is 6-6.5. Retains more than 70% of the maximum agglutinating activity over the pH range 5-9. Unchanged hemagglutinating activity after 30 minutes incubation at temperatures up to 50 degrees Celsius, then at higher temperatures activity decreases. 14% of the initial activity is retained even after heating at 100 degrees Celsius. Homodimer. Contains a single ricin B lectin domain with a characteristic beta-trefoil fold consisting of three repeated subdomains each containing a more or less conserved QXW motif. The N-terminus is blocked. Potential for use as natural insecticide.