Objective: To evaluate emergency prophylactic effects of the avian influenza virus immunized serum on experimentally infected mice.
Methods: Serum HI antibody titers of 30 mice were detected at day 1 to 19 after being inoculated with 0.2 ml immune serum to estimate half life of immune serum. Ten mice clinical symptom was recorded to estimate the serum security after mice injected 1.5 ml immune serum. Seventy mice were randomly divided into 7 groups according to random number table and inoculated with 0.2 ml, 0.1 ml and 0.05 ml immune serum respectively via intraperitoneal injection on day 8, 4 and 1 prior to challenged with 10 LD(50) influenza virus intranasal. Mice were observed continually for 14 days to calculate the morbidity, mortality, average survival days and compare the lung index and viral titers in lung.
Results: Serum HI antibody titers of mice which inoculated with 0.2 ml immune serum maintained 2(6) in 15 days after injection, but drawdown after day 17, the mice injected 1.5 ml immune serum were all alive and none onset. The survival rate of mice which injected 0.2 ml serum on the day 8, 4, 1 before challenge was 80%, 100% and 100%, and the average survival period was 13.1 days, 14.0 days and 14.0 days respectively. The survival rate of mice which injected 0.1 ml and 0.05 ml serum on day 1 before challenge was 100% and 50%, and the average survival days were 14.0 days and 11.7 days respectively. The mice lung index of experimental groups (0.0096 +/- 0.0033 - 0.0145 +/- 0.0060) was smaller than that of viral control group (0.0199 +/- 0.0025), with a statistical significance (P value 0.0022 - 0.0470, < 0.05). The viral titers in lung were significantly decreased by 2 titer as compared to the viral controls.
Conclusion: The avian influenza virus immunized serum might contain the emergency prophylactic effects and could be developed as an agent for possible human-avian influenza pandemic.