Pseudomonas aeruginosa protease IV: a corneal virulence factor of low immunogenicity.
OBJECTIVE
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.
Thibodeaux
Brett A
BA
Department of Microbiology, Louisiana State University Health Sciences Center, New Orleans, 70112, USA.
Caballero
Armando R
AR
Dajcs
Joseph J
JJ
Marquart
Mary E
ME
Engel
Lee S
LS
O'Callaghan
Richard J
RJ
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D015153:Blotting, Western; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D007114:Immunization / Q000379:methods*; D066298:In Vitro Techniques; D007634:Keratitis / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D010447:Peptide Hydrolases / Q000096:biosynthesis / Q000276:immunology / Q000627:therapeutic use*; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000254:growth & development / Q000472:pathogenicity; D011817:Rabbits; D011994:Recombinant Proteins / Q000276:immunology / Q000627:therapeutic use; D016896:Treatment Outcome; D037521:Virulence Factors / Q000096:biosynthesis / Q000276:immunology / Q000627:therapeutic use*
D000907:Antibodies, Bacterial; D011994:Recombinant Proteins; D037521:Virulence Factors; D010447:Peptide Hydrolases; C030732:protease IV