Gold nanoparticle-aided preparation of antibodies to α-methylacyl-CoA racemase and its immunochemical detection

Current laboratory and morphological differential diagnosis of prostate cancer is based on the use of sensitive tumor-specific markers. One of the most promising tumor markers is alpha-methylacyl-CoA racemase (AMACR), and studies indicate a positive correlation between AMACR expression, degree of tumor differentiation, and tumor progression. Most commonly, AMACR is detected by immunohistochemical means. Here, we took advantage of the adjuvant properties of colloidal gold nanoparticles to prepare rabbit polyclonal anti-AMACR antibodies and compare them with commercially available monoclonal anti-AMACR antibodies. The sensitivity of both antibody types, as determined by ELISA, was comparable and close to 1 mu g mL(-1), whereas a gold nanoshell-aided immunodot assay demonstrated eight times higher sensitivity for polyclonal gold-derived anti-AMACR antibodies. The rabbit polyclonal anti-AMACR antibodies were used in immunohistochemical analysis of biopsy specimens collected from patients with different prostate pathologies. The intensity of AMACR detection in prostate epithelium cytoplasm differed significantly between the groups of patients with prostate adenoma and with prostate cancer.