PURPOSE: COPD is a severe chronic and progressive disorder and is the fourth leading cause of death in the US. Acute and chronic inflammatory diseases are known to induce changes in protein glycosylation of plasma glycoproteins, leading to increased sialylation of A1PI in acute, or to hypogalactosylation of IgG in chronic disease states. However, very little is known about the transfer from plasma into bronchoalveolar lavage fluid (BAL) and its possible effect on the glycosylation of these proteins, which are important for the protection of lung tissue.
METHODS: IgG and A1PI were purified from plasma using protein-G and thiol-interaction chromatography, respectively. These proteins were enriched from BAL fluid using solid phase extraction on C4-resins. Standard glyco-proteomic approaches were used to identify proteins and perform site-specific structural N-glycan mapping.
RESULTS: The N-glycans of IgG from BAL fluid were mainly of the agalacto form, which is rare in normal human plasma IgG. However, IgG from plasma of this particular COPD patient showed the same glycan profile as the BAL IgG. The N-glycans of A1PI did not differ greatly from those identified for A1PI of a normal human plasma.
CONCLUSION: Even though chronic inflammation has been found to affect the N-glycosylation profile of IgG, the N-glycosylation of A1PI has not been found to be affected by this disease state. The transport process from plasma to BAL fluid appears to have no effects on the particular N-glycosylation of the analyzed glycoproteins.
CLINICAL IMPLICATIONS: This approach enables specific characterization of proteins and their glycosylation present in BAL fluid and showed that glycosylation of the analyzed proteins in BAL mirrors the one identified in plasma.
DISCLOSURE: Daniel Kolarich, Employee A. Weber, PL. Turecek and HP. Schwarz are employed by Baxter BioScience; Other J. Stadlmann, F. Altmann and D. Kolarich received honoraria from Baxter Bioscience; Product/procedure/technique that is considered research and is NOT yet approved for any purpose, The material and methods applied for the enrichment and identification of the analyzed proteins are not approved for therapeutical use.