Immunogenicity of Inactivated Newcastle Disease Virus Preparations

Formalin has been the most widely used inactivating agent in the production of Newcastle disease virus vaccines. Many investigators (1, 2, 6, 7, 8, 17, 18, 19, 22, 23) have reported generally good results with formalin-inactivated preparations of Newcastle disease virus (NDV). Others (5, 12, 15, 20) have reported poor or partial immunity following its use. Brandly et al. (4) and Hanson et al. (11) found some differences in immunogenicity between strains of virus when inactivated with formalin and used as vaccines. Beta-propiolactone has come into use recently as a promising inactivating agent in preparing NDV vaccines (16, 21). Bower and Eisenstark (3) reported preliminary results with urethane used as the inactivating chemical. Iyer and Dobson (14) and Doyle and Wright (9) reported on the use of crystal violet NDV vaccine. Dutcher et al. (10) used rapid heating as a means of inactivating NDV for vaccines. This report presents the results of experiments designed to evaluate the immunogenicity of NDV preparations inactivated by gamma radiation, formalin, and beta-propiolactone (BPL).