Radioimmunoassay for serum and urinary lysozyme

Area of Science:

• Biochemistry
• Immunology
• Clinical Chemistry

Background:

• Lysozyme (EC 3.2.1.17, mucopeptide N-acetylmuramohydrolase) is an enzyme with diagnostic relevance.
• Accurate quantification of lysozyme in biological fluids is crucial for various clinical conditions.

Purpose of the Study:

• To develop and validate a sensitive radioimmunoassay for lysozyme quantification.
• To assess the assay's performance in plasma and urine samples.

Main Methods:

• Development of a radioimmunoassay utilizing rabbit-raised antibodies against purified lysozyme.
• Incubation of diluted antiserum with radiolabeled lysozyme, followed by separation using dextran-coated charcoal.
• Assay validation through precision, parallelism studies, and comparison with a turbidimetric lytic assay.

Main Results:

• The radioimmunoassay demonstrated good precision and reproducibility.
• Results correlated well with a Micrococcus lysodeikticus lytic assay (r = 0.94).
• The assay achieved a sensitivity of 3.5 micrograms/L for both serum and urine.

Conclusions:

• The developed radioimmunoassay is a precise, reproducible, and sensitive method for measuring lysozyme in plasma and urine.
• This assay is suitable for clinical applications requiring accurate lysozyme level determination.