DETERMINATION OF THE NEUTRALIZING POTENCY OF HORSE ANTIVENOM AGAINST BOTHROPIC AND CROTALIC VENOMS BY INDIRECT ENZYME-IMMUNOASSAY

The use of ELISA to determine antisnake venom potency of horse immune sera should provide benefits of cost and reproducibility compared to i n vivo assays. In the present investigation we evaluated the correlati on between ELISA antibody levels and bl vivo neutralization assays. Fo r the indirect ELISA method, 0.016 mu g/well of Bothrops jararaca or C rotalus durissus terrificus venom were used to coat the plates and 100 mu l/well of each sample of antibothropic or anticrotalic venom sera were used at 1:10;000 dilution. Sheep anti-horse IgG conjugated to per oxidase was added and the substrate H2O2/o-phenylenediamine produced t he color that was read at 492 nm. A correlation coefficient of r = 0.9 7 was found far anticrotalic venom antibodies and no significant corre lation was observed for antibothropic venom sera using 16 serum sample s from immunized horses. However, when three antibothropic venom sera showing high in vivo neutralization potency and low absorbance in ELIS A or high absorbance values and low in vivo protection were not includ ed in the correlation analysis the coefficient value was r = 0.88. The correlation coefficient did not improve for all 16 antibothropic sera when a partially purified Bothrops jararaca venom fraction was used t o coat the ELISA plates. The results indicate that ELISA could be used to determine the neutralizing potency of anticrotalic venom sera. For the antibothropic venom sera further studies are needed.