Cross-species identification of novel Candida albicans immunogenic proteins by combination of two-dimensional polyacrylamide gel electrophoresis and mass spectrometry

We have previously reported the usefulness of two-dimensional gel electroph oresis followed by Western blotting with sera from patients with systemic c andidiasis in the detection of the major Candida albicans antigens (Pitarch st al., Electrophoresis 1999, 20, 1001-1010). The identification of these antigens would be useful for the characterization of good markers for the d isease, and for the development of efficient diagnostic strategies. In this work we have used nanoelectrospray tandem mass spectrometry to obtain amin o acid sequence information from the immunogenic proteins previously detect ed. We report here the cross-species identification of these antigens by ma tching of tandem mass spectrometry data to Saccharomyces cerevisiae protein s. Using this approach, we unambiguously identified the four C. albicans im munogenic proteins analyzed, namely aconitase, pyruvate kinase, phosphoglyc erate mutase and methionine synthase. Furthermore, we report for the first time that aconitase, methionine synthase and phosphoglycerate mutase have a ntigenic properties in C. albicans.