Sensitive and Selective Immunofluorescence Assay for CA15-3 Detection Using Fluorescein Derivative A10254.

Area of Science:

• Biochemistry
• Immunology
• Medical Diagnostics

Background:

• Carbohydrate antigen 15-3 (CA15-3) is a crucial serum biomarker for breast cancer monitoring, recurrence prediction, and metastasis detection.
• Conventional Enzyme-Linked Immunosorbent Assay (ELISA) for CA15-3 has a high limit of detection (>1 U mL-1), necessitating more sensitive methods for early diagnosis.

Purpose of the Study:

• To develop a novel, highly sensitive, and selective immunofluorescence assay for effective CA15-3 detection.
• To establish a convenient method for earlier breast cancer prognoses.

Main Methods:

• A sandwich immunofluorescence assay format was developed using antibody-coated solid phase to capture CA15-3.
• A10254-labeled antibody II was used for antigen recognition, and fluorescence signals were quantified using a microplate reader.
• The assay involved capturing CA15-3 with immobilized antibody I and detecting it with A10254-labeled antibody II.

Main Results:

• The immunofluorescence assay achieved lower limits of detection (0.11 and 0.18 U mL-1) in buffer and 2% serum, respectively.
• A linear detection range of 0.25-14 U mL-1 was established for the assay.
• The assay demonstrated good specificity and reproducibility in 2% serum, with low relative standard deviations.

Conclusions:

• The developed immunofluorescence assay significantly enhances the performance compared to conventional CA15-3 ELISA kits.
• The assay's accuracy and reproducibility in diluted serum suggest its potential for clinical breast cancer diagnosis.