Enrichment of Interleukins and Low Abundance Proteins from Tissue Leakage in Serum Proteome Studies Using ProteoMiner Beads

Abstract

Human serum contains among others interleukins and tissue leakage proteins, for example basic myelin protein. These proteins are present in serum at very low concentrations ranging from several picograms to low nanograms per milliliter. Although the presence of these proteins in serum reflects the physiological condition of the human body and may be used as disease biomarkers for clinical diagnosis or prognosis, their detection remains a great challenge due to the presence of high abundance serum proteins such as albumin, immunoglobins and others. ProteoMiner TM is a protein fractionation technology based on a combinatorial peptide library bound to chromatographic beads and is used to reduce the amount of the high abundance serum proteins and to increase the relative amount of low abundance proteins. To determine whether ProteoMiner TM could facilitate the detection of interleukins and proteins from tissue leakage in serum, we mixed an artificial serum using the 12 most abundant serum proteins (albumin, IgG, haptoglobin, retinol binding protein, myelin basic protein, troponin, IL-8, IL-2 etc)., tissue leakage proteins and interleukins in the concentration ranges reported for normal human serum. Subsequently, this artificial serum sample was fractionated by ProteoMiner technology. The proteins in ProteoMiner bound fraction were further separated either via 2-dimensional gel electrophoresis followed by mass spectrometric protein identification or the low abundance proteins were detected via western blotting with the unfractionated artificial serum serving as control.