A novel lectin from the large globiferous pedicellariae of the sea urchin, Toxopneustes pileolus, was isolated by a combination of gel chromatography and affinity chromatography techniques. The 32 kDa lectin appeared to have sequence homology to SUL-I, a D-galactose-specific lectin (Nakagawa et al., 1999). This lectin is named SUL-IA. The N-terminal 7 amino acid sequence of SUL-IA was shown to be AVGRSCE. SUL-IA induced mitogenic stimulation on murine splenocytes and T-lymphocytes. SUL-IA also induced chemotaxis for guinea-pig neutrophils and macrophages. In addition, SUL-IA produced IFN-gamma in a higher dose range, but not IL-4. These results suggest that SUL-IA may be a biologically functional lectin, which is one of the multiple lectins from the pedicellarial venom of T. pileolus.