TABLE 2.
Antibody titers of different IgG preparations used
| Serum | Antigen used in immuno-fluorescence assay
|
Coagglutination with purified PIA (titer) | |
|---|---|---|---|
| 1457 (PIA positive) (titer) | 1457-M11 (PIA negative) (titer) | ||
| Anti-PIA | 1:128 | <1:32 | 1:1024 |
| Normal rabbit serum | <1:32 | <1:32 | Negative |
| Anti-5179 (PIA-negative) | 1:512 | 1:512 | Negativea |
| Anti-1457 (PIA-positive) | 1:1024 | 1:1024 | 1:256 |
a
As a coagglutination reagent prepared with anti-5179 displayed autoagglutination, probably by cross-reaction with S. aureus, the antiserum was diluted 1:50 in phosphate-buffered saline and absorbed with an overnight culture of the biofilm-negative, PIA-negative S. epidermidis 5179 before preparation of the coagglutination reagent. A coagglutination reagent prepared with anti-PIA serum absorbed in parallel displayed a titer of 1:512.