Antitumor Activity of Glycosylated Molluscan Hemocyanins via Guerin Ascites Tumor

Abstract

As observed in most molluscan hemocyanins, high-mannose type glycans were identified in hemocyanins from Rapana venosa (RvH), Helix lucorum (HlH) and keyhole limpet (Megatura crenulata). In addition, a glycan with a branching structure containing xylose, fucose and terminal methyl hexose was identified in β-HlH. We have examined the immuno-adjuvant properties of hemocyanins, their derivatives and conjugates associated with the cell mediated immunity in experimental tumor-bearing animals with ascites tumor of Guerin. After immunization of the animals with the experimental vaccine preparations, the highest values of splenic lymphocytes were observed in groups immunized with the conjugates RvH-TAg, β-HlH-TAg and KLH-TAg (42.3%; 40.8% and 40.58%, respectively) than with the native hemocyanins (36.5%; 35.1% and 32.4%, respectively). The immunization of rats with the hemocyanins β-HlH, RvH and KLH and their conjugates, prolonged the median survival time of tumor-bearing animals compared with non-immunized animals (39, 33, 31 and 7 days, respectively). Both hemocyanins β-HlH and RvH activate the immune system of the experimental animals and therefore could be a good alternative for KLH. For this reason they could be included into the composition of non-specific anti-tumor vaccines to enhance their effectiveness.

• GAT
• Helix lucorum
• hemocyanin
• Rapana venosa

ACKNOWLEDGMENTS

This work was financially supported by the research grant from the National Research Foundation of Bulgarian Ministry of Education and Science: My-CC 1501/05, UV-L-301/2007, TK01-496/2008 and DFG-01/2008 (Germany). We thank to the National Snail Breeding Cluster (NOC) and “Delta Industry” AD, Sozopol, for providing the snails.

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.