BACKGROUND: Numerous assays have been described for the detection of p53 autoantibodies. These assays are highly specific with low sensitivity. In this report, the authors describe a highly sensitive and simple particle agglutination immunoassay using superparamagnetic particles for capturing p5 autoantibodies, p53 protein, and p53 protein-antibody complexes from large volumes of serum samples (2 mL). METHODS: Superparamagnetic particles were coated with different peptides spanning the entire p53 protein. These particles were incubated with serum samples from healthy blood donors (n=180), from patients without malignancies (n=27), and from patients with various forms of lung cancer (n=166). The particles were washed and placed into the reaction chamber of a gel card. After centrifugation, agglutination results were read visually. Positive reactions were defined by a layer of particles on top of the gel or agglutinated particles dispersed through the gel matrix. RESULTS: Depending on the peptide used, p53 autoantibodies were detected in from 17.5% to 35% of the investigated patients with lung cancer. By using a commercially available enzyme-linked immunoadsorbent assay (ELISA) kit, p53 autoantibodies were detected in only 3% of those patients. P53 protein and p53 protein-antibody complexes were not detected in patients with lung cancer (n=20). CONCLUSIONS: The newly developed assay was easy to perform and had sensitivity superior to that of the currently available p53 ELISAs. Copyright (c) 2007 American Cancer Society.
BACKGROUND: Numerous assays have been described for the detection of p53 autoantibodies. These assays are highly specific with low sensitivity. In this report, the authors describe a highly sensitive and simple particle agglutination immunoassay using superparamagnetic particles for capturing p5 autoantibodies, p53 protein, and p53 protein-antibody complexes from large volumes of serum samples (2 mL). METHODS: Superparamagnetic particles were coated with different peptides spanning the entire p53 protein. These particles were incubated with serum samples from healthy blood donors (n=180), from patients without malignancies (n=27), and from patients with various forms of lung cancer (n=166). The particles were washed and placed into the reaction chamber of a gel card. After centrifugation, agglutination results were read visually. Positive reactions were defined by a layer of particles on top of the gel or agglutinated particles dispersed through the gel matrix. RESULTS: Depending on the peptide used, p53 autoantibodies were detected in from 17.5% to 35% of the investigated patients with lung cancer. By using a commercially available enzyme-linked immunoadsorbent assay (ELISA) kit, p53 autoantibodies were detected in only 3% of those patients. P53 protein and p53 protein-antibody complexes were not detected in patients with lung cancer (n=20). CONCLUSIONS: The newly developed assay was easy to perform and had sensitivity superior to that of the currently available p53 ELISAs. Copyright (c) 2007 American Cancer Society.