A solid-phase enzyme immunoassay of thromboxane B2.

Area of Science:

• Biochemistry
• Analytical Chemistry
• Immunology

Background:

• Thromboxane B2 (TXB2) is a key metabolite in hemostasis and thrombosis.
• Accurate quantification of TXB2 is crucial for understanding related pathologies.
• Existing methods may have limitations in sensitivity, specificity, or cost.

Purpose of the Study:

• To develop and validate a solid-phase enzyme immunoassay for quantifying thromboxane B2.
• To assess the assay's sensitivity, specificity, and applicability to biological samples.
• To compare the developed assay with established radioimmunoassay methods.

Main Methods:

• A competitive solid-phase enzyme immunoassay was developed using thromboxane B2 conjugated with beta-galactosidase.
• Anti-thromboxane B2 IgG was immobilized on polystyrene tubes.
• Enzyme activity of bound beta-galactosidase was measured fluorimetrically.
• Sample preparation involved extraction and concentration using an octadecylsilyl silica column, followed by reverse-phase HPLC for purification.

Main Results:

• The assay accurately determined thromboxane B2 in the range of 20 fmol to 14 pmol.
• High specificity was observed, with minimal cross-reactivity from related prostaglandins and metabolites (e.g., 18.6% for 2,3-dinor-TXB2, 0.4% for 2,3,4,5-tetranor-TXB2).
• The enzyme immunoassay showed good recovery (~80%) in human plasma and correlated well with radioimmunoassay (r = 0.979).
• Analysis of human urine revealed 2,3-dinor-TXB2 as the predominant detected metabolite.

Conclusions:

• A sensitive and specific solid-phase enzyme immunoassay for thromboxane B2 has been successfully developed.
• The assay is suitable for quantifying TXB2 in biological samples like human blood and urine, following appropriate sample preparation.
• This method provides a viable alternative to radioimmunoassay for TXB2 determination.