Lectins in the hemolymph of Japanese horseshoe crab, Tachypleus tridentatus

The hemolymph of the Japanese horsehoe crab, Tachypleus tridentatus contains lectins which agglutinate mammalian erythrocytes. Affinity chromatographic purification of the lectins using bovine submaxillary gland mucin-conjugated Sepharose resulted in the separation of the lectins into four fractions; one major and three minor lectins. Protein subunits revealed by polyacrylamide gel electrophoresis and the immunoprecipitin line of these lectins against antiserum to crude lectins were unique to each fraction. The activities of all the lectins were optimal at pH values between 6 and 8, and were destroyed by heating at 60°C. Calcium chloride augumented the activities of three lectins, but the major lectin was not influenced by the salt. Bovine erythrocytes were not agglutinated by any of the lectins and comparative agglutination titers for other erythrocytes from various sources were different among these lectins. The activities of all the lectins were inhibited by N-acetylamino sugars. They were more effectively inhibited by glycoproteins which contain sialic acid.