Toxin-neutralizing effect and activity-quality relationship for mice tetrodotoxin-specific polyclonal antibodies

The polyclonal antibodies specific for tetrodotoxin (TTX) were prepared from mice and their capacity of neutralizing TTX was investigated so as to explore the possibility of developing TTX antitoxin. Haptenic TTX was conjugated to Tachypleus tridentatus hemocyanin (TTH) chemically to form artificial antigen TTX-TTH. BALB/c mice were immunized with TTX-TTH and ascites were induced by intraperitoneal administration of Freund's adjuvant. Twenty strains of TTX-specific ascites antibody with apparent affinity varying from 10−4 to 10−7 M were obtained. KM mice were challenged with lethal doses (1LD = 14.0 μg/kg, i.p.) of TTX neutralized by antibodies to evaluate the power of antitoxin. The potential of TTX-neutralizing of the antibodies was approved by the increase in survival animal challenged by lethal doses of TTX pre-incubated in vitro or neutralized in vivo with TTX specific antibodies. The highest protection was observed with all animals survived challenge of 1.5 × LD TTX neutralized in vitro, and antibody administration 4 days prior to 1.3 × LD TTX challenge in vivo neutralization. The protective efficiency was antibody quality factor dependent and with the highest detoxifying immunological equivalent as high as 1 300 μg TTX/Lascites approximately, while the antibody apparent affinity being at the order of 10−6 to 10−7 M. These results suggested that chemical vaccine for haptenic TTX could successfully raise high humoral immune response and the antibodies could neutralize TTX effectively both in vitro and in vivo, antibody therapy would be the hopeful means for detoxification of TTX.