Recombinant Expression and Purification of Human Cystatin C Biomarker in Escherichia coli for Prediagnostic Renal Disorders

  Chronic kidney disease is a worldwide health problem and Glomerular filtration rate (GFR) is the most frequently used criteria in the assessment of rental function. Cystatin C as a member of type 2 cystatin superfamily and cysteine-protease inhibitor is found in high concentrations in all biological fluids. This study is aimed to study cystatin C as a potent biomarker for clinical measurement of renal disorders and other diseases. In this study, the human cystatin C construct was analyzed by bioinformatics software. It was cloned and expressed to produce an appropriate antigen for anti-cystatin C (anti-Cys C) obtained from mice Balb/C as a crucial point in the improvement of an enzyme-linked immunosorbent assay (ELISA) method. Serum samples were given from 32 hospitalized patients with renal failure and cardiovascular disease and non-hospitalized patients were tested by ELISA method using anti-Cys C obtained from mice Balb/C. Our findings indicated 0.36-2.4 mg/L as the best conclusion for antigen cystatin C in patients’ sera and 1/50 dilution for anti-Cys C obtained from mice Balb/C and showed a relationship between patients with high creatinine and high concentration of cystatin C. In case of five cardiovascular disease patients with normal upper limit of Creatinine we obtained cystatin C lower than kidney failure and raising of cystatin C in 6 patients with increased TSH were seen. Polyclonal anti-Cys C antibodies were obtained through the immunization of Balb/C mice can be employed as an anti-Cys C in ELISA for diagnosis of some renal dysfunction.