Figure 4.

pH treatment of abrin has no detrimental effect on toxin activity. (A) A single concentration of 100 ng/mL abrin was used in cell free translation assays for all pH conditions. There is no significant difference between the various pH-exposed toxins. Values represent means of triplicate samples ± SD. Statistical significance was determined by two-tailed unpaired Student’s t-test. The data represents a single experiment; (B) pH-treated toxins were administered to mice iv at a lethal dose of 1 μg per mouse (n = 5 mice per experimental condition) for one experiment. There was no detrimental effect on abrin’s ability to cause intoxication and subsequent death. Survival curves were plotted for mice for each condition and the log-rank (Mantel–Cox) test was used to evaluate statistical significance on GraphPad Prism 6. The only statistical significant decrease in toxicity was seen in abrin treated at pH 3.0 which shortened the time-to-death compared to abrin treated at pH 7.0 (** p = 0.0027).