Humoral immune responses and safety of experimental formulations of inactivated Neospora vaccines

Antibody titers to Neospora antigens ranged from 40 to 160 before vaccinati on, from 80 to 5,120 2 weeks after the first dose of vaccination, and 320 t o 40,960 2 weeks after the second (booster) vaccination. A peak antibody ti ter of 40,960 was also detected 28 days after the booster vaccination among animals vaccinated with Neospora vaccine formulated with Bay R1005 adjuvan t. In heifers inoculated with experimental formulations of Neospora vaccine s, transient development of injection site reactions resulted in 1 out of 1 5 animals. This injection site reaction was not detectable 14 days after th e first observation and measurements were made. We have also demonstrated t hat vaccines derived from tissue-culture-grown Neospora tachyzoites are saf e and would be expected to be efficacious.