PTH and infection: Thus, PK10C7 did not neutralize infection of PTH while PK3D1 showed moderate neutralizing activity down to a dilution of 1:102 (about 200 ng/ml) which proved to be at least as good as the standard murine MA18/7 anti-pre-S1 mAb used as positive neutralization standard (1:100, corresponding to a concentration of 10 μg/ml) (Fig 2).