Reaginic antibody in cattle hypersensitised by foot-and-mouth disease vaccine.

The passive cutaneous anaphylaxis test (PCAT) in calves and goats was used to demonstrate reaginic antibody in the sera of cattle which had shown anaphylaxis following injection with foot-and-mouth disease vaccine. A period of two or three days between the intracutaneous injection of test sera and the intracutaneous or intravenous challenge with components of vaccine was found to be satisfactory. Positive reactions were obtained in calves for up to 49 days but many goats failed to react after eight days. The PCAT had a high degree of reproducibility within any one test animal, but a marked variation was found between individual test animals.