The Retinol-binding Protein And Its Monoclonal Antibody In Clinical Testing

In recent years, renal tubular diseases have aroused the public's attention due to its ever-increasing incidence in urinary system dysfunctions. Updated data show that 20%-40% of the chronic renal failure is caused by renal tubular diseases. When the renal tubular is impaired, some proteins will be urinated, and detection of these markers is contributive to the early diagnosis and medication.Retinol binding protein (RBP) is a carrier protein, which is primarily synthesized in the liver and responsible for transporting retinol from liver to target cells. RBP formed a protein complex with retinol and transthyretin (TTR) in the circulation system. After releasing retinol in the periphery of target cells, RBP dissociates from the RBP-retinol-TTR complex, circulating in the blood. RBP is re-absorbed in the proximal renal tubules and then degraded for the synthesis of new proteins. When renal tubules are impaired, RBP will be detected in the urine, which makes it an ideal marker for the diagnosis of renal tubular diseases.Currently, RBP antibodies are primarily acquired by immunization of purified proteins from human fluids. However, the complicated purification process and low retrieving rate has made the task cost-inefficient. To avoid this obstacle, we use E.coli system to produce recombinant RBP and obtain two monoclonal antibodies: S-59-1 and S-59-2, with high affinity to nature RBP. Via the antibody replacement assay with a commercialized ELISA kit, we found that the two mAbs are equally competent for either detection or coating in sandwich ELISA, which paves the way for the R&D of RBP diagnosis kit.