Leptospiral vaccines: immunogenicity of protein-free medium cultivated whole cell bacterins in swine

Swine serologically negative for anti-Leptospira antibodies were given 2 doses of a pentavalent vaccine (3 weeks between doses) prepared from Leptospira serovars canicola, icterohaemorrhagiae, hardjo, pomona, and grip-potyphosa (0.2 mg/serovar/dose). Leptospires used for vaccinal production were cultivated in a protein-free medium or in a bovine albumin-containing medium. All vaccinated swine had demonstrable antibody titers within 1 week of the initial vaccination. Peak microscopic agglutination titers were between 256 and 1,024 after the 2nd vaccinal dose was given. After challenge exposure with serovar canicola, control swine had titers of at least 13,653 and the vaccinated swine had titers of 3,403 to 8,192, depending on the vaccine. Leptospiremia and kidney infections were not detected in any canicola Moulton immunized swine, but did appear in control swine. The Al(OH)3 adjuvant had no obvious influence of any of the vaccinal titers.