Figure 5: In vitro protection of J774A.1 cells against LeTx challenge. (a) In vitro neutralization assay showed that LF8-Fab could protect cells against LeTx in a dose-dependent manner, with an EC50 of 85 μg/mL according to calculation of SPSS statistical software. The percentage of viability was demonstrated by GraphPad Prism software. (b) In vitro LeTx challenge study to test neutralization effect of LF8-Fab before or after LeTx exposure of J774A.1 cells at different time points. Minus (−) means LF8-Fab prior to LeTx, while plus (+) means LeTx prior to LF8-Fab. LF8-Fab could completely neutralize LeTx and protect cells as long as the treatment was prior to LeTx addition. As for the converse situation, protection effect declined in a time-dependent manner.