Allergy in cattle after foot-and-mouth disease vaccination

BHK cell derivatives, saponin and aluminium hydroxide, all of which are commonly present in foot-and-mouth disease vaccines, were injected subcutaneously into 10 cattle and the serum levels of anti-BHK reagins and passive haemagglutinating antibodies were followed. The reaginic antibodies rose to a peak titre one to two weeks after the stimuli and waned during the third week. They had a serum half life of about three days, assuming exponential decay, and were generally undetectable four weeks after last contact with antigen. Passive haemagglutinins were slower to develop and two or more stimuli were usually required to produce detectable antibody levels. They were also slower to subside and were demonstrable for at least 10 weeks after last contact with antigen in most cases. Clinical reactions provoked by the intradermal injection of lysate into sensitised cattle were not correlated with the serum reagin or passive haemagglutinin levels or their ratio to one another at time of the reactions. The reasons for this are discussed.