Lactose-Specific Hemagglutinin with In vitro Opsonic Effect from the Hemolymph of Ariadne merione (Cramer)

The present study was designed to detect the presence of Hemagglutinin (HA) molecule, which recognizes and responds to foreign bodies, in the serum of Ariadne merione. On screening the natural hemagglutinating (HA) activity using various mammalian erythrocytes as indicator cells, highest hemagglutination titer was observed with rat erythrocytes. In cross adsorption tests, this RBC type was able to completely adsorb all the HA activity in serum. Further analysis of the physico-chemical properties revealed that this HA is dependent on Ca2+ for its activity, irreversibly sensitive to EDTA, stable only at pH 7 and thermo-labile. Its proteinaceous nature was confirmed by its susceptibility to trypsin and -mercaptoethanol. HA-inhibition assays with mono-, di-, tri- and polysaccharides revealed that the serum HA is specific for lactose with non-reducing terminal galactose possessing 14 glycosidic linkage. Subsequent role of this HA in mediating cellular immune response revealed that phagocytotic index was enhanced by 6-fold in vitro indicating the opsonic effect of the agglutinin.