Detection and identification of human bronchoalveolar lavage proteins using narrow-range immobilized pH gradient DryStrip and the paper bridge sampleapplication method

The use of two-dimensional gel electrophoresis as a tool for the investigat ion of human bronchoalveolar lavage fluid (BALF) has been hampered by techn ical difficulties. In the last decade attempts have been made to establish a two-dimensional (2-D) protein map of BALF samples, resulting in the ident ification of a number of proteins present in BALF. In this study, we report an improved sample handling and separation protocol for investigation of h uman BALF proteins. The sample has been analyzed by employing a number of s trategies, including the 'paper bridge' sample application method in combin ation with narrow range immobilized pH gradient (IPG) DryStrips, followed b y comparison to the corresponding plasma map. Using peptide mass fingerprin ting, we have identified 49 proteins in the narrow pH range 4.5-5.2 from an individual healthy BALF sample. Furthermore, we identified 17 BALF protein s, not detected in plasma. Twelve of these proteins have, to our knowledge, not previously been described in the BALF 2-D map. The mapping of BALF pro teins with inclusion of those at low concentration increases the possibilit y to subsequently screen patient material for disease markers.