Antibodies as means for selective mass spectrometry

• The combination of affinity enrichment and mass spectrometry is reviewed.
• This combination results in a gain in both sensitivity and specificity.
• Developed technologies for protein analysis and quantification are discussed.
• This is a growing area of research with the aim to enter the clinic.

For protein analysis of biological samples, two major strategies are used today; mass spectrometry (MS) and antibody-based methods. Each strategy offers advantages and drawbacks. However, combining the two using an immunoenrichment step with MS analysis brings together the benefits of each method resulting in increased sensitivity, faster analysis and possibility of higher degrees of multiplexing. The immunoenrichment can be performed either on protein or peptide level and quantification standards can be added in order to enable determination of the absolute protein concentration in the sample. The combination of immunoenrichment and MS holds great promise for the future in both proteomics and clinical diagnostics. This review describes different setups of immunoenrichment coupled to mass spectrometry and how these can be utilized in various applications.