Proteome of monocytes primed with lipopolysaccharide: Analysis of the abundant proteins

Abstract

We performed a proteomic analysis of monocytes primed by lipopolysaccharide (LPS) in vitro, using two‐dimensional gels stained with Coomassie blue. We found 16 proteins of ∼500 detected that either increased or decreased in abundance as a result of priming by LPS (14 with P ≤ 0.05). The proteins were identified by comparing the masses of their tryptic peptides with those of all known proteins, using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and the SWISS‐PROT database. Identities were confirmed by matching the sequence of several tryptic peptides, using liquid chromatography electrospray‐ionization quadrupole ion trap mass spectrometry. There were increases in the protective enzymes superoxide dismutase and catalase, in four calgranulins, in the cytokine pre‐B cell enhancing factor, and in annexin 2, macrophage capping protein, transketolase, pyruvate kinase, and serine/threonine protein kinase 10. Proteins that decreased in abundance were integrin alpha‐IIB, protein disulfide isomerase, and platelet‐activating factor acetylhydrolase. Many of these altered proteins have interesting functions in inflammation.