Evaluation of immune response and protection in animals given mink parvovirus vaccines

In orthogonal and pair design tests, mink, guinea-pigs and rabbits were inoculated with inactivated mink enteritis virus (MEV) vaccine prepared with mineral oil or Al(OH)3 gel adjuvant. The animals were examined for serum haemagglutination-inhibition (HI) antibody during 6-55 days postvaccination (p.v.) and serum-neutralizing (SN) antibody for 11-31 days p.v. Differences between mineral oil and Al(OH)3 gel adjuvant vaccines in the induction of HI and SN antibodies during 6-55 days p.v. were not significant. There was significant positive rank correlation between HI antibody level and SN antibody index from 11 to 31 days p.v. in serum of mink inoculated with the mineral oil or Al(OH)3 gel adjuvant vaccine (P < 0.05). The results of experimental challenge tests with vaccines in 29 mink showed a positive correlation between HI antibody titres, SNI and immune protective rates. Levels of HI antibodies in guinea-pigs, rabbits or mink during 11-40 days p.v. were reliable indices for monitoring the humoral immune responses and immune protective rates. The criteria for virus vaccine potency and vaccine immune efficiency is an HA titre of 64 for the cell-cultured MEV and an HI antibody titre of 32 for guinea-pigs, rabbits or mink during 11-40 days p.v. The vaccine stimulates a protective response which lasts for a period of 12 months. The vaccine is stable for a period of 9 months at 4 degrees C. Economic, simple and scientific means have been developed to monitor the quality of MEV vaccines, of which more than 70,000 doses of the mineral oil vaccine and more than 18,000,000 doses of the Al(OH)3 gel vaccine have been used for the last 5 years.