Effect of common protective antigen vaccination to protect mink from challenge exposure with Pseudomonas aeruginosa.

The protein portion of endotoxin (OEP), or common antigen of Pseudomonas aeruginosa prepared from strain N10 of P aeruginosa, was examined as a possible vaccine against this organism in mink. Mink were given OEP vaccine and challenge exposed by instillation with the inoculum into the nostril. They survived after this exposure with 4 median lethal (LD50) doses of strain NC-5 (protease negative, elastase negative) or with 160 LD50 doses of strain 5 (protease positive, elastase positive). Strain NC-5 belonged to TYPE 5 AND strain 5 belonged to type 8 (according to the serotyping method of Homma). Strain N10, the source of OEP, belonged to serotype 5. Thus, the mink vaccinated with OEP vaccine were able to stand challenge exposure to both homologous and heterologous serotype strains. More mink given OEP vaccine survived the challenge exposure by intranasal spraying with virulent strain 5 than did those in the nonvaccinated control group, with a significant difference. When the surviving mink of the vaccinated group were rechallenge exposed with 300 or 3,000 LD50 doses of the same strain a month later, most of them survived.