Fibronectin (FN)-immunoreactivity of affinity-purified gelatin-binding proteins from human seminal plasma. (A): Immunoblot analysis: affinity-purified gelatin-binding proteins from human seminal plasma were resolved by SDS-PAGE, blotted onto Immobilon-P–PVDF membrane and probed with monoclonal anti-plasma FN antibody (Ab) (a) and monoclonal anti-cellular FN Ab (b). Bound antibody was visualized using biotinylated anti-mouse IgG Ab followed by avidin/biotinylated-HRPO mixture and by addition of DAB substrate solution. Numbers indicate molecular mass (kDa). (B): On-chip immunoaffinity profiling: monoclonal anti-plasma FN antibody (a) or monoclonal anti-cellular FN antibody (b) were immobilized on preactivated surface (PS20) ProteinChip array and allowed to react with affinity-purified gelatin-binding proteins, as described in Materials and methods. On-chip immunoaffinity captured molecules were detected by SELDI-TOF mass spectrometry in ion-positive mode at 25 kV and analyzed using CiphergenExpress Software 3.0 ( (BioRad, Hercules, CA, USA)). Calibration was performed with ProteinChip all-in-one protein standards II. The mass region of 8–17 kDa is shown.