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Updated: Aug 17, 2026

Generation of In-Frame Gene Deletion Mutants in Pseudomonas aeruginosa and Testing for Virulence Attenuation in a Simple Mouse Model of Infection
Published on: January 8, 2020
Pseudomonas aeruginosa protease IV: a corneal virulence factor of low immunogenicity
Brett A Thibodeaux1, Armando R Caballero, Joseph J Dajcs
1Department of Microbiology, Louisiana State University Health Sciences Center, New Orleans, 70112, USA.
Purpose:
To study antibody production to Pseudomonas aeruginosa protease IV (PIV) for immunoassay development and to assess the possible role of antibody in arresting corneal damage.
Methods:
Rabbits were immunized with PIV, urea-soluble recombinant PIV (rPIV), or precipitated rPIV. Antibody was analyzed by ELISA and Western blotting. Antibody-mediated inhibition of PIV activity was tested by colorimetric assay and during keratitis by slit-lamp examination of infected eyes.
Results:
Antibody was not produced after PIV immunization but was induced by rPIV. Rabbits immunized first with soluble and then precipitated rPIV produced high titers (log(10)) to rPIV (4.28 +/- 0.09) and significantly higher titers to PIV (3.90 +/- 0.06) compared to the other immunized groups. Antibody to rPIV reacted with PIV, but neither neutralized enzyme activity in vitro nor protected infected rabbits in vivo.
Conclusions:
The present study demonstrates that PIV is a virulence factor which can escape a protective immune response.
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