Cystatin C is a low-molecular-weight protein belonging to the cystatin superfamily of cysteine protease inhibitors, primarily produced by nucleated cells. It plays a crucial role in regulating intracellular and extracellular proteolysis by inhibiting cathepsins, enzymes involved in protein degradation. Unlike creatinine, cystatin C is less influenced by age, gender, muscle mass, or diet, making it a reliable biomarker for estimating glomerular filtration rate (GFR) and diagnosing early-stage kidney dysfunction.
Antibodies targeting cystatin C are essential tools in both research and clinical diagnostics. These antibodies enable quantitative detection of cystatin C levels in biological fluids (e.g., blood, urine) using immunoassays like ELISA, immunoturbidimetry, or chemiluminescence. Monoclonal and polyclonal antibodies are developed against specific epitopes of cystatin C, ensuring high specificity and sensitivity in distinguishing it from other cystatin family members.
Clinically, cystatin C antibody-based assays are widely adopted to monitor renal impairment, particularly in cases where creatinine-based assessments are unreliable. Beyond kidney disease, elevated cystatin C levels correlate with cardiovascular risks, neurodegenerative disorders (e.g., Alzheimer’s), and certain cancers, expanding its utility as a multifunctional biomarker. Recent studies also explore cystatin C's role in immune regulation and its potential as a therapeutic target.
In summary, cystatin C antibodies are pivotal in advancing diagnostic accuracy and understanding the protein's pathophysiological roles across diverse diseases.