Breeding line-specific BALF glycoprotein expression on day 20 post infection by fluorescence based 2-D gelelectrophoresis (2-D DIGE). Glycoprotein fractions from three animals of each breed were pooled and labelled by different CyDyes before two dimensional separation: German Landrace = Cy2 (blue), Piétrain = Cy3 (green), and Hampshire = Cy5 (red). Proteins identified are indicated by a number/captial letter combination referring to Table I; potential isomers for which mass spectrometry gave no results are marked with lower case letters.