FIG. 1.

Fractionation of P388D₁ cells infected with serovar Typhimurium strains expressing plasmid-encoded hybrid YopE proteins. Lanes 1, whole-cell lysate of non-cell-associated bacteria; lanes 2, bacterium-free infection medium; lanes 3, Triton X-100-insoluble fraction containing internalized bacteria; lanes 4, Triton X-100-soluble P388D₁ cell lysate containing translocated proteins. The total protein amounts obtained from all four fractions were loaded. Chimeric YopE proteins were detected by protein immunoblotting with a MAb to M45.