Inhibitory activity of mouse, human and guinea pig sera.

Shown are the average EC50 values, standard deviation (SD) and fold-change in EC50 for PLY, PFO and SLO when treated with sera from mice, humans and guinea pigs compared to the EC50 obtained in the absence of sera (toxin sample is serially diluted in PBS or sera in PBS). Each sera tested was matched to its own individual PBS positive control. The fold change = EC50 in the presence of serum/EC50 in PBS, and is shown in parenthesis. Results from 3 independent experiments are shown. *Inhibition of SLO by human serum likely due to high SLO antibody titers, which were 47,000 to 128,000, depending on the serum lot. Inhibitory activity of mouse, human and guinea pig sera.