Enriching for Low-Abundance Serum Proteins Using ProteoMiner™ and Protein-Level HPLC

The mammalian immune system acts to protect the body from harmful diseases ranging from cancer to infection. Differentially expressed proteins as a result of such an immune response can shed light on the mechanism of disease or serve as biomarkers. These biomarkers can be used in a diagnostic capacity or as correlates of protection following vaccination. Protein levels in the circulatory system are considered representative of the system as a whole, making serum an ideal matrix for surveilling immune responses. However, serum proteomics using mass spectrometry is extremely challenging due to the complexity of the matrix and the dynamic range of protein concentration. This chapter will describe two orthogonal enrichment strategies that can be used sequentially or in isolation to improve the identification of low-abundance serum proteins by mass spectrometry.