STUDIES ON HUMORAL IMMUNE RESPONSE OF TRIONYX SINENSIS TO AEROMONAS SOBRIA INACTIVED VACCINE

An enzyme linked-immunosorbent assay(ELISA)for detection of Aeromonas sobria(As)antibody in Chinese soft-shelled turtle(Trionyx sinensis,Ts)was developed. Chinese soft-shelled turtle antibody was purified by sephadex and DEAE-52.Then inoculated into the New Zealand white rabbit with Freund complete adjuvant.Rabbit anti-turtle IgG was also purified and coagulated with Horseradish peroxidase(HRP).It was determined by square titration method that a dilution of 1:3200 of this enzyme complex was optimal in terms of test sensitivity.Immune serum was collected at different time after the turtles were immunized with Aeromonas sobria(As)-TL970424 inactived vaccine once or twice.ELISA methods were applied to detecting the change of antibody in serum.The result indicated that Chinese soft-shelled turtle could mount good humoral immune response as well as the second immune response to As inactived vaccine.However this second immune response is weak when compared to that of mammals.Challenge test was carried out 90 days after immunization.No mortality was recorded with turtles injected once whereas there was 100%mortality from group of non-immunized turtles.This result indicated that As inactived vaccine was effective in protecting immunized turtles from attack of this bacteria within 3 monthes post immunization.