Identification and characterization of thymosin beta-4 in chicken macrophages using whole cell MALDI-TOF

The aim of the study was to determine chicken monocyte- and granulocyte-associated peptides and proteins using "whole cell" matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and to characterize the peptides based on their abundance. The mass spectra showed a prominent peak at m/z 4963 in monocytes/macrophages but not in the granulocytes. Subsequent purification and characterization of the m/z 4963 peptide from an avian macrophage cell line HTC, revealed it to be thymosin beta-4 (Tbeta-4), an actin-modulating peptide. HTC cells when treated with bacterial lipopolysaccharide and peptidoglycan to determine the modulation of Tbeta-4 gene expression or its secretion, showed no changes.