Figure 4

Growth in cholesterol specifically enhances cell surface display of Lewis antigens. Whole cell ELISA assays were performed on samples of H. pylori strain 26695 (upper left), SS1 (lower left), or G27 (upper and lower right). Parallel cultures were grown overnight in defined medium containing 130 μM of the following additions: circles, no addition; squares, cholesterol; triangles, β-sitosterol; X, taurocholate. Varying amounts of cell suspension corresponding to known amounts of cellular protein were applied to duplicate wells of ELISA plates, and immunoassayed for the presence of Lewis X or Lewis Y antigen as described in Methods. Negative control samples of E. coli HB101, or buffer-only blanks, fell on the dotted line. Absorbance readings for individual wells are plotted. Repeat experiments with three or more independently grown cultures have yielded essentially identical results.