Cytokine detection by antibody-based proximity ligation

Area of Science:

• Biochemistry
• Molecular Biology
• Assay Development

Background:

• Proteome analysis requires sensitive detection techniques and specific binding reagents.
• The proximity ligation assay (PLA) offers sensitive protein measurements by converting protein detection to DNA sequence analysis.
• Previous PLA methods utilized DNA molecules for both binding and ligatable arms.

Purpose of the Study:

• To generalize the proximity ligation mechanism by enabling the use of antibodies as protein binders.
• To develop convenient protocols for converting antibodies into proximity probes.
• To demonstrate the application of antibody-based PLA for sensitive protein detection in small sample volumes.

Main Methods:

• Developed protocols to attach oligonucleotide sequences to polyclonal or monoclonal antibodies, creating proximity probe sets.
• Prepared reagents for over 100,000 proximity ligation assays from 1 microgram of antibody.
• Applied the antibody-based PLA to measure cytokines in a homogenous assay format.

Main Results:

• Successfully converted antibodies into functional proximity probes.
• Achieved femtomolar detection sensitivities for cytokine measurements.
• Demonstrated high-capacity protein measurements in 1-microliter samples.
• Showcased the utility of the method for analyzing minute sample amounts.

Conclusions:

• The generalized proximity ligation method effectively utilizes antibodies for sensitive and high-capacity protein detection.
• This technique significantly enhances proteome analysis capabilities, especially when sample volumes are limited.
• The antibody-based PLA provides a versatile platform for various biological and diagnostic applications.