Highly sensitive ELISA-based assay for quantifying protein levels in neuronal cultures

Area of Science:

• Cell Biology
• Biochemistry
• Immunology

Background:

• Quantifying protein expression in situ is crucial for understanding cellular processes.
• Existing methods can be complex or lack sensitivity for live cell analysis.
• Developing a straightforward, high-throughput assay for in situ protein quantification is needed.

Purpose of the Study:

• To present a simple, sensitive, and adaptable assay for quantifying protein expression levels directly within cell cultures.
• To demonstrate the assay's utility for live cell analysis and in vivo labeling applications.
• To leverage Enzyme-Linked Immunosorbent Assay (ELISA) principles for enhanced quantification in cell-based assays.

Main Methods:

• Incubating surface-attached cells (fixed or live) with a primary antibody specific to the target protein.
• Applying a peroxidase-conjugated secondary antibody followed by a soluble peroxidase substrate (tetramethylbenzidine).
• Quantifying antibody binding via optical density measurements at 450 nm using an ELISA-based protocol.

Main Results:

• The assay is highly sensitive, capable of detecting proteins in a single layer of cells in a 96-well plate.
• Demonstrated successful optimization and application in P19 neuronal cell lines, including in vivo labeling of neurons.
• The method is applicable to any surface-attached cell culture, offering broad utility.

Conclusions:

• This assay provides a simple, sensitive, and reproducible method for quantifying protein expression in situ within cell cultures.
• It extends the advantages of ELISA, such as wide sensitivity range and high throughput, to live cell analysis.
• The assay is valuable for studying cellular responses and protein dynamics in various cell types and experimental conditions.