Testing serum specificity for bacterial antigens in a mouse model of spontaneous colitis

Identification of bacterial antigens within cecal bacterial lysate was performed by using serum antibodies from control and DC-LMP1/CD40 animals for immunoprecipitation followed by label-free liquid chromatography tandem mass spectrometry (LC-MS/MS). Serum antibodies were coupled to beads and incubated with cecal bacterial lysate to bind target proteins. Upon immunoprecipitation, on-beads digestion of proteins followed by LC-MS/MS was performed. The resulting peak intensities were used for intensity-based quantification (iBAQ). Proteins identified with a fold change > 2 and a p-value < 0.05 were considered for further analyses.