Human Kallikrein 13: Production and Purification of Recombinant Protein and Monoclonal and Polyclonal Antibodies, and Development of a Sensitive and Specific Immunofluorometric Assay

Abstract
Background: The aims of this study were to develop immunologic reagents and a sensitive and specific immunoassay for human kallikrein 13 (hK13) and to examine the presence of hK13 in human tissues and biological fluids. Methods: Recombinant hK13 protein was produced and purified with use of a Pichia pastoris yeast expression system. The protein was used as an immunogen to generate mouse monoclonal and rabbit polyclonal anti-hK13 antibodies. A sandwich-type immunoassay was developed with these antibodies. The assay was used to measure hK13 in various biological fluids and tissue extracts. Immunohistochemical analysis was also performed on nondiseased and cancerous prostatic sections. Results: The hK13 immunoassay had a detection limit of 0.05 μg/L and showed no cross-reactivity with homologous kallikreins. The assay was linear at 0–20 μg/L, and within-and between-run CVs were Conclusions: This immunofluorometric assay for hK13 may be used to examine the value of hK13 as a disease biomarker and to further explore the physiologic and pathobiologic role of this enzyme in human disease.