FIG. 2.

Inhibition of hemagglutination by different IgG preparations. Serial dilutions of biofilm-producing PIA-positive S. epidermidis 1457 were applied to each well of a microtiter plate. Each well contained (at concentrations of 75 μg/ml) the IgG preparation of normal rabbit serum (normal RABBIT), antiserum raised against purified PIA (anti-PIA), antiserum raised against whole cells of the biofilm-negative, PIA-negative S. epidermidis 5179 (anti-5179), and antiserum raised against whole cells of the biofilm-producing, PIA-positive S. epidermidis 1457 (anti-1457). Control wells contained no IgG and only phosphate-buffered saline (PBS). The hemagglutination titers were assessed as described in Materials and Methods.