Fig. 1. Differential binding of Shiga anCd cholera toxin to Vero cells; differences in gene expression in Shiga versus Cholera toxin binding Vero cells. (a) Differential binding of Cy3-CTX (CTX-Cy3) and Cy2-ST (ST-Cy2) to non-synchronized Vero cells. Cells were incubated simultaneously with the two labeled toxins for 10 minutes at 0°C. Unbound toxins were washed away and the live cells observed by fluorescence microscopy. (b) Differential display comparing ST binding cells (S) and CTX binding cells (C). Non-synchonized Vero cells were labeled simultaneously with Cy2-ST and Cy3-CTX as in (a) and separated by FACS. cDNA was synthesized from RNA extracted from ST and CT binding cells. DNA fragments were produced by PCR using different 5' and 3' primers and analyzed by PAGE. The results of the primer pairs P2/T1, P2/T2, P2/T3, and P2/T4 are shown (see Methods section). Note the differentially amplified cDNA fragments marked by (^*).