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Mycoplasma hyorhinis is an important pathogen of swine that can often occur as a respiratory coinfection with viral pathogens, but can also cause arthritis and polyserositis in infected animals. To date, no assay is available to assess the serologic response to M. hyorhinis vaccines, to our knowledge. We used recombinantly expressed M. hyorhinis p37 protein to monitor the magnitude of the IgG response in vaccinated animals. The assay was able to distinguish animals vaccinated with M. hyorhinis from those vaccinated with the other important Mycoplasma species: M. hyopneumoniae and M. hyosynoviae. When formulated with an ideal adjuvant, inactivated vaccines designed to protect animals against M. hyorhinis induced a measurable and dose-dependent antibody response against the p37 protein. Additionally, the protein appears to be highly conserved between strains of M. hyorhinis isolated in the United States. The specificity of the assay as well as the conservation and immunogenicity of the p37 protein make it an ideal candidate antigen for use in measuring the immune response against M. hyorhinis after vaccination in weaned pigs.

The immunogenicity of leptospires cultivated in modified bovine albumin-polysorbate 80 medium and those cultivated in protein-free medium were quantitatively evaluated in the dog. Vaccine preparations, whole cell or outer envelope, prevented leptospiremia; however, kidney culture data revealed that 1 of 4 dogs vaccinated with 0.1 to 1 mg of whole cell prepared from leptospires cultivated in the modified bovine albumin-polysorbate 80 medium was positive for Leptospira, whereas dogs vaccinated with whole cells prepared in protein-free medium were not. Dogs vaccinated with greater than or equal to 0.5 mg of outer envelope were refractory to infection after challenge exposure.

The humoral immune response of dogs vaccinated with leptospiral pentavalent outer envelope and whole culture vaccines was monitored with the microscopic agglutination (MA) test and leptospiricidal activity (LA) test for a 2-year period. The leptospiral serovars in the vaccines was canicola, icterohaemorrhagiae, grippotyphosa, pomona, and hardjo. The LA test was markedly more sensitive than the MA test for detecting anti-Leptospira antibodies and was least noticeable with anti-pomona antibodies. Both Igm and IgG were produced in similar amounts in the vaccinated dogs, and both classes of immunoglobulins were reactive in the MA and LA tests. The IgM class of antibodies was slightly more reactive in the MA test, whereas IgG antibodies were somewhat more reactive in the LA test. A direct correlation between protective antibodies, as determined by the hamster passive-protection test, and antibodies reactive in the MA and LA tests was observed.

The humoral immune response of cattle vaccinated with leptospiral pentavalent outer envelope and whole culture vaccines was monitored with the microscopic agglutination (MA) test and the leptospiricidal activity (LA) test for a 2.5-year period. The serovars present in the vaccines were canicola, icterohaemorrhagiae, grippotyphosa, pomona, and hardjo. The LA test had greater sensitivity than the MA test for detecting antibodies to the hardjo, canicola, and icterohaemorrhagiae components of the pentavalent vaccine and was approximately equal in sensitivity to the MA test for detecting antibodies to the grippotyphosa and pomona components of the leptospiral vaccine. Both IgM and IgG were produced in similar amounts in the immunized cattle, and both classes were reactive in the MA and the LA tests. The IgM class of antibodies was more reactive in the MA test, whereas the IgG class of antibodies was more reactive in the LA test. Using the MA test as the criterion of evaluating, the immunogenic potency of the individual vaccine components was found to be canicola more than icterohaemorrhagiae more than grippotyphosa more than pomona more than hardjo. A direct correlation between protective antibodies, as determined by the hamster passive protection test, and antibodies reactive in the MA and the LA tests was observed.

Dogs inoculated intranasally with a live avirulent Bordetella bronchiseptica vaccine were monitored for the development of resistance to experimentally induced infectious tracheobronchitis (canine cough). Dogs were challenge exposed with a virulent strains of B bronchiseptica at various times after they were vaccinated. Clinical protection was detectable as early as 48 hours. At postvaccination days 4, 5, and 14, 56%, 83%, and 95% protection was observed. Humoral immunoglobulin (Ig) titers ranged from 1:8.6 on day 0 to 1:147 on postvaccination day 21. In the monitoring of B bronchiseptica-specific secretory IgA by indirect immunofluorescence, titers appeared as early as day 4 after vaccination. The IgA titers ranged from 1:16 on day 4 to 1: 1,024 on day 21. The appearance of IgA titers correlated with the development of resistance to clinical infection.

The immunogenicity of 2 leptospiral cell structural components, the outer envelope (OE) and protoplasmic cylinder (PC), as well as the leptospire whole cell (WC), was compared in hamsters and dogs. The 50% protective dose for hamsters against death (PD50D) and kidney infection (PD50k) was evaluated for Leptospira interrogans serovars canicola, icterohaemorrhagiae, pomona, and grippotyphosa. All 3 immunogens had similar PD50D values. However, the PD50K values for OE and WC vaccines ranged from 0.05 to 0.80 micrograms (dry weight), whereas the PC vaccines ranged from 7.0 to 14.0 micrograms. Cellular and humoral responses of dogs to serovar canicola WC, OE, and PC vaccines were monitored for 21 weeks. Little difference was observed among the canine humoral responses to the different preparations. Protoplasmic cylinder vaccines sensitized the greater population of lymphoid cells followed by OE and WC. Cross-reactivity was greater in the blastogenic response of lymphoid cell populations than in the humoral response.

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.