Characterization of the monoclonal antibody that inhibits bacterial internalization into TG cells. (A) Inhibition of bacterial internalization by the R2–25 antibody treatment. Data are the averages of triplicate samples from three identical experiments, and the error bars represent the standard deviations. Statistically significant differences between bacterial internalization into TG cells treated with the R2–25 antibody and those treated with rat IgG are indicated by asterisks (*, P < 0.01). (B) Distribution of protein reacting with monoclonal antibodies in TG cells. The left panels show fluorescence microscopy of the antibody stained TG cells and the right panels phase contrast microscopy of the corresponding microscopic fields. (C) Immunoblot analysis was performed on TG cell subcellular fractions with the monoclonal antibodies R2–25. Cells were fractionated to cytoskeleton (csk), nucleus (nuc), membrane (mem) and cytosol (cso). The anti-histone H1 and anti-β-tubulin antibody were used for fraction control for the nucleus and cytoskeleton.