Physico-chemical characterization of a natural agglutinin from the hemolymph of a millipede Thyropygus descriptus
Keywords:millipede, Thyropygus descriptus, agglutinin, hemolymph, erythrocytes, hemagglutination assay, hemagglutination inhibition assay
Natural hemagglutinins with specific affinity for the glycocalyx of rabbit erythrocytes is identified in the hemolymph of the millipedes, Thyropygus descriptus, Xenobolus acuticonus, Arthrosphaera disticta and A. craspedota. Of the tested species, maximum hemagglutinability is observed in the hemolymph of the millipede Thyropygus descriptus. Further characterization of the hemolymph agglutinin of Thyropygus descriptus showed optimum agglutinability at pH 6.5 and temperatures 30 - 35 ºC. Starvation up to 20 days had no influence on the hemagglutinability of the hemolymph. Agglutinability was impervious by change in diet, and inclusion of diverse concentrations of cations or chelators in the buffer. The agglutinin, though agglutinates rabbit, rat and human A erythrocytes, when pre-adsorbed with erythrocytes of a particular species, loses its ability to agglutinate erythrocytes of any species suggesting the presence of a single agglutinin in the hemolymph. In general, the agglutinating activity of the agglutinin is inhibited by the glycoproteins porcine stomach mucin, lactoferrin, bovine submaxillary mucin, transferrin, fetuin and the sugars N-acetyl galactosamine, Nacetyl lactosamine, lactose, galactose and N-acetyl neuraminic acid. The sialic acid specificity of the agglutinin is revealed by the reduction in hemagglutination activity when treated with the desialylated rabbit erythrocytes.