Complete two-dimensional gel electrophoresis pattern of de novo synthesized acute phase reactants

The early stages of inflammatory responses are characterized by the rapid synthesis of a heterogenous group of plasma proteins known as acute phase reactants. We show that the complex changes in the serum protein composition of mice in response to infections can easily be analysed by two-dimensional (2D) gel electrophoresis, which allows simultaneous analysis of numerous proteins from small volume samples. While changes in the protein composition can be visualized by silver staining, radiofluorography of gels loaded with serum samples from mice that had been labelled in vivo with 35S-methionine allows an analysis of the changes in the pattern of protein synthesis. Thus, these techniques should allow the evaluation of the relative contributions of alterations of protein synthesis and catabolism to the changes in the overall concentration of individual acute phase reactants. Identification of proteins in the 2 D gel pattern can be easily accomplished by co-electrophoresing small serum samples together with immunoprecipitates obtained from in-vivo labelled serum. Using this approach we were able to identify some of the major acute phase reactants of mice. Some of these proteins, like haptoglobin and haemopexin, show concentration increases that are characteristic for type III reactants like C-reactive protein (CRP) or serum amyloid A component (SAA) in man. Results obtained with serum from healthy and infected human newborns indicate that 2D gel electrophoresis could be used to analyse changes in human plasma protein profiles, which would make it a valuable tool for diagnosis and management in certain clinical situations.