Cl. Schwartzkoff et al., THE EFFECTS OF ANTIGENIC-COMPETITION ON THE EFFICACY OF MULTIVALENT FOOTROT VACCINES, Australian Veterinary Journal, 70(4), 1993, pp. 123-126
A multivalent footrot vaccine has been developed, containing pilus ant
igens produced in recombinant Pseudomonas aeruginosa and representing
all nine serogroups of Dichelobacter (Bacteroides) nodosus commonly re
cognised in the field. The responses of sheep to the multivalent vacci
ne have been compared with those to monovalent vaccines representing o
nly a single serogroup. Antigenic competition between serogroups occur
red in sheep immunised with the multivalent formulation, but high leve
ls of protection were still achieved. The study showed that in multiva
lent footrot vaccines, antigenic competition is predominantly due to t
he presence of a family of immunologically-related pilus antigens rath
er than to interference by extraneous proteins.