Immunological properties of cellular and whole-culture leptospiral bacterins

ABSTRACT

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