Analysis of porcine peripheral blood mononuclear cells proteome by 2-DE and MS: analytical and biological variability in the protein expression level and protein identification

In this paper, we present the protein map corresponding to the porcine peripheral blood mononuclear cells (PBMC) to better understand the role of these cells in the pig immune system. To conform the map, the proteins were separated by 2-DE using a 5-8 range pH gradient in IEF and approximately 800 spots were detected. Due to the high level of indeterminate variability associates to the 2-DE, analytical and biological variances were analyzed. The analytical variance was calculated for 50 proteins in three replicate 2-DE gels from the same protein extract whereas the biological variance was determined by comparison of the patterns obtained for the same 50 proteins in different animals. Values of 15.13 and 33.70% were determined for analytical and biological variances, respectively. These average variances will provide a quantified and statistical basis for future proteomic studies directed to evaluate relevant quantitative changes in the biological response. A representative set of the major proteins was subjected to MALDI-TOF analysis and over 75% of the proteins were identified on the basis of their similarity with its human homologue proteins. A large number of cytoskeletal and metabolic proteins were found as well as some proteins related to cell mobility and immunological functions. Finally, other proteins implicated in the cell signaling process, transport or apoptosis were also identified giving a wide overview of the porcine PBMC protein map.