Figure 1

Neutralization of the RNA-NGA of Stx2 by the A subunit-specific antibodies. The letters 'H', 'M' or 'L' within parenthesis after a HuMAb designation represent high, medium or low HeLa cell cytotoxicity-neutralization groups of the antibodies, respectively. The HuMAbs 2F10, 3E9, and 5C12 were the strongest in blocking the RNA-NGA of Stx2 since visual inspection (Fig. 1A and 1C) and semi-quantitative densitometry analysis (Fig. 1B and 1D) of the luciferase bands showed that the amount of produced in the presence of these antibodies was similar to that translated in the absence of Stx2 ("no Stx2" lane). The luciferase band analysis also revealed that the neutralization of RNA-NGA of Stx2 by medium Stx2-cytotoxicity neutralizing group antibodies 6H5, 6H7, 7C4, 14C12, 5E12, 6D8 and 6B7 was moderate since relative expression of the luciferase bands was between 0.60 - 0.80. The expression of the luciferase bands in presence of the other 3 antibodies (9H9, 6C3 and 1G1) of the medium Stx2-cytotoxicity neutralizing group was weaker (relative expression of the luciferase bands between 0.40 - 0.60) than the other antibodies of this group but still better than that of the low Stx2-cytotoxicity neutralizing group antibodies. The expression of the luciferase bands in presence of the low Stx2-cytotoxicity neutralizing group antibodies (4H10, 6E6, 1G12, 3A2, 5F2, and 7F2) was very weak (relative expression of the luciferase bands <0.40). The experiment was repeated once with similar results.