Effects of binary ethylenimine (BEI) treatment on the inactivation of infectivity and hemagglutinin of Newcastle disease virus (NDV) were studied in comparison with those of formalin treatment. Immune responses of chickens vaccinated with BEI-inactivated NDV vaccines were also investigated.
The results were summarized as followings :
1. Complete loss of infectivity of NDV (Bl) was observed at 3,7, and 24 hours after the treatment at 37℃ with BEI concentrations of 0.01M, 0.005M and 0.001M, respectively.
2. The hemagglutinin activity of NDV (Bl) remained constant when treated with 0.01M BEI at 37℃. However, it gradually decreased when treated with 0.1% or 0.2% formalin at 37℃.
3. When 4-week-old chickens were vaccinated with NDV vaccines prepared from Bl or Miyadera strains of NDV, inactivated with 0.1M BEI and adsorbed to aluminium hydroxide gel, favorable immune responses were observed throughout the 8 weeks of observation period.
4. When these chickens were revaccinated at 8 weeks after the first vaccination, strong anamnestic responses were evoked and the immunity maintained for 4 weeks of the observation. Though slightly bettor immune responses were observed after primary vaccination in chickens vaccinated with Bl vaccine compared with those vaccinated with Miyadera vaccine, the differences were not significant.
5. On the electron microscopy, BEI (0.01M) gave least effect to the envelope as well as capsid of NDV
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