Carrier-Guided Proteome Analysis in a High Protein Background: An Improved Approach to Host Cell Protein...

Area of Science:

• Proteomics
• Biotechnology
• Analytical Chemistry

Background:

• Shotgun proteomics struggles with highly abundant proteins masking low-abundance targets.
• Residual host cell proteins (HCPs) are critical quality attributes in biotherapeutics.
• Existing methods like ELISAs lack the comprehensive identification capabilities of mass spectrometry.

Purpose of the Study:

• To develop a carrier proteome approach using tandem mass tags (TMT) for enhanced detection of low-abundance proteins.
• To improve the identification of residual host cell proteins (HCPs) in complex protein mixtures.
• To address challenges in mass spectrometry-based proteomics caused by high-abundance background proteins.

Main Methods:

• Utilized tandem mass tags (TMT) to introduce a carrier proteome strategy.
• Employed a mixture of bovine serum albumin (BSA) and *E. coli* for proof-of-principle experiments.
• Implemented a spike-in interference detection TMT channel to mitigate co-isolation interference.

Main Results:

• Demonstrated improved detection of low-abundance proteins against a high-abundance background.
• Successfully identified 300 residual *E. coli* proteins from a human IgG antibody sample.
• Quantified and mitigated co-isolation interference using a specific TMT channel.

Conclusions:

• The TMT-based carrier proteome approach significantly enhances low-abundance protein detection in complex samples.
• This method shows promise for accurate HCP analysis in biotherapeutic protein formulations.
• The strategy offers a valuable tool for comprehensive proteomic profiling in challenging biological matrices.