Fig. 5. Cellular fractionation reveals the presence of vesicular flagellin not associated with bacteria. T84 model epithelia were colonized with S. typhimurium for 1 hour after which epithelia were disrupted and fractionated by centrifugation as described in Materials and Methods. Fractions were normalized for protein content and then analyzed by SDS-PAGE and immunoblotting for bacterial GroEl and flagellin. This data is representative of several experiments.