Immunological properties of cellular and whole-culture leptospiral bacterins

Two bivalent leptospiral bacterins were compared for safety in guinea pigs and for potency in hamsters. One bacterin [Bacterin A] was prepared from the cellular material of Leptospiral icterohaemorrhagjae and Leptospira canicola cultures propagated in Stuart's modified medium with 7% rabbit serum. The 2[nd] bacterin [Bacterin B] contained whole leptospiral cultures grown in synthetic medium. Neither bacterin induced adverse local or systemic reactions when injected intraperitoneally [I/P] in guinea pigs. In hamsters, 1/400 and 1/800 of the recommended dose of bacterin B for cattle protected 100% of the vaccinated hamsters against challenge exposure of either virulent leptospiral serotype A dose representing 1/400 of the recommended dose of bacterin A for cattle protected 80% of vaccinated hamsters against challenge exposure to L. icterohaemorrhagjae and 90% against challenge exposure to L. canicola, whereas the 1/800 dose level protected only 10% of the vaccinated hamsters challenge exposed to virulent culture of L. icterohaemorrhagjae or canicola. The Possibility was demonstrated that at least one soluble antigen of strong immunogenic properties is produced in cultures of L. icterohaemorrhagjae and L. canicola

Immunological assay after vaccination of goats with brucella melitensis rev.I and brucella abortus 45/20 vaccines at Saudi Arabia

The living smooth Brucella melitensis Rev. I vaccine given in the normal dose [7x10[8] organism] to goats 3 to 5 months of age stimulated a marked increase in agglutinin titer. Fractionation of pools of serum by gel filtration by anion exchange chromatography, using diethylaminoethyl [DEAE] cellulose showed that both IgM and IgG agglutinins were present from 12 to 47 days after goats were vaccinated. Only mercaptoethanol [ME]- sensitive agglutinins were detected in most goats 4 months after vaccination, but 2 of 30 goats retained ME- resistant agglutinins for the 13 1/2 - month observation period. Fractionation of serums from goats representative of these 2 types of serologic response indicated that most goats had only IgM agglutinins whereas the 2 given goats had activity in the IgG fraction. Adult goats given Brucella abortus 42/20 adjuvant vaccine and revaccinated 5 months later developed low agglutination titers to smooth antigen, and all became test Positive to the antiglobulin test. Fractionation of serum of pools taken 1 week and 8 months after revaccination indicated that antibody activity was restricted to the IgG fraction. Sera from 5 vaccinated and nonvaccinated goats which were Positive by bacteriological culture examination at necropsy 31 to 47 days after goats were given conjunctival inoculation of virulent B. melitensis had antibody activity in both IgG and IgM fractions Test Positive reaction to the ME, complement-fixation [CF], and antiglobulin [AG] test were restricted to the IgG-containing fractions of serum whereas reactions to the agglutination [STT] and the card tests appeared with either or both fractions. The effect of these findings on the choice of tests for the differentiation of vaccination response is discussed

Comparison of standard tube and microagglutination techniques for determining brucella abortus antibodies

A microagglutination method for determining the agglutinating and blocking antibodies to Brucella abortus is described. A collection of sera from cattle in 2 rural areas of Saudi Arabia were tested by the microagglutination methods and the standard methods in tube. The results were compared and showed that where discrepancies occurred, these were due to the microagglutination methods being more sensitive. It is concluded that these are suitable methods for screening animal stocks