IMMUNOREACTIVITY OF A NEW-GENERATION OF HORSE F(AB')(2) PREPARATIONS AGAINST EUROPEAN VIPER VENOMS AND THE TETANUS TOXIN

The immunoreactivity of the current and the purified, pasteurized prep arations of horse F(ab')(2) against the tetanus toxin and Vipera aspis venom was investigated with a biosensor based on technology using the optical phenomenon of surface plasmon resonance. Immunoreactivity dat a were compared with seroneutralization titres. to investigate immunor eactivity-immunoprotection efficacy relationships. To association-diss ociation rate and affinity constants of the current and the new tetanu s toxin-specific F(ab')(2) preparations were similar, at about 10(4) M (-1) sec(-1), 10(-4) sec(-1) and 10(8) M(-1), respectively. Similar va lues were found using a solid immunoradiometric assay. To assess the i mmunoreactivity of V. aspis venom-specific horse F(ab')(2), the mol. w t and percentage of the antigenic fractions of V. aspis venom were det ermined. Western blotting of electrophoresis gels showed four antigeni c fractions of V. aspis venom (mel, wts 17,500, 28,500, 32,000 and 60, 000), which represented 6, 3.4, 17.7 and 5% of total venom, respective ly. Association and dissociation rate constants were in the same range as those of the tetanus toxin-F(ab')(2) interactions for each of the four antigenic fractions. Seroneutralization of both tetanus toxin and V. aspis by the corresponding specific F(ab')(2) showed that the LD(5 0) mg(-1) protein was 1.76-fold and 1.51-fold higher with the new than with the current preparations, respectively. These improvements in ef ficacy were in close agreement with the higher immunoreactive fraction ratios, which were 2-fold and 1.8-fold higher with the new preparatio ns. These results demonstrate that the removal of non-IgG, immunoglobu lins and the pasteurization treatment have no overall influence on F(a b')(2) affinity but improve the specific activity of these new antitox in horse F(ab')(2). (C) 1997 Elsevier Science Ltd.