Z. Bercovich et Jam. Muskens, THE SENSITIZING EFFECT OF A BRUCELLA-ABORTUS ANTIGEN IN CATTLE AFTER REPEATED INTRADERMAL INOCULATIONS, Veterinary microbiology, 51(1-2), 1996, pp. 85-93
An antigen prepared from a mucoid strain of B. abortus was repeatedly
injected intradermally into cattle to determine whether it sensitizes
cattle so that they test false positive with the skin delayed-type hyp
ersensitivity (SDTH) test. Cattle (n = 14) that were experimentally in
oculated with microorganisms that serologically cross-react with B. ab
ortus, and uninfected cattle (n = 15) were tested with the antigen 2 t
o 5 times over a period of 16 to 17 weeks. An increase in skinfold thi
ckness of greater than or equal to 2.0 mm on the injection site was co
nsidered a reaction elicited by the antigen. The sera from the cattle
were tested with the serum agglutination test, complement fixation tes
t, and an enzyme-linked immunosorbent assay for antibodies against B.
abortus. Results showed that none of the animals had an increase in sk
infold thickness of greater than or equal to 2.0 mm on the injection s
ite of the antigen, which is considered a positive reaction. However,
cattle experimentally inoculated with microorganisms other than B. abo
rtus tested seropositive for brucellosis after one SDHT test only. We
conclude that the B. abortus antigen inoculated intradermally does not
sensitize cattle after repeated inoculations, and therefore does not
interfere with the subsequent use of the SDTH test in the diagnosis of
brucellosis.