FIG 5.

The combination of 2A6 and 8A7 enhanced protection against LeTx. (A) The viability of J774A.1 cells was measured using the MTT assay in the presence of 2A6 alone or in combination with 8A7. The concentration of 8A7 was held constant at 0.05 μg/ml, and 2A6 was titrated from 1 μg/ml. ***, P < 0.05 for absence of 8A7 versus corresponding presence of 8A7, by t test. (B) The viability of J774A.1 cells was measured using the MTT assay in the presence of 2A6 alone or in combination with 8A7. The concentration of 2A6 was held constant at 0.1 or 0.05 μg/ml, and 8A7 was titrated from 1 μg/ml. Data shown are means ± SDs from at least three independent experiments, each conducted in duplicate. (C) Fischer 344 rats (n = 5/group) were challenged with LeTx (10 μg of PA and 10 μg of LF per rat) and simultaneously injected with 2A6 alone, 8A7 alone, or the combination (the molar ratio of antibodies to PA was 1:1 or 0.5:1). Survival time is shown. NS Ab, nonspecific antibody.