Figure 5

Determination of the HAV neutralization potency of human IG preparations by ELISA. HAV-Bsd was treated with 1% IG preparations as indicated in Figure 4 and titrated in 96-well plates containing Huh7-A-I cells. Four-fold serial dilutions of the neutralization reactions were inoculated in 8 wells per dilution and incubated in the absence of blasticidin for 2 weeks at 35°C. Cells were fixed and stained with anti-HAV mAb K2-4F2 and peroxidase-labeled goat anti-mouse antibodies. TMB substrate was added and color development was stopped by acidification. Absorbance at 450 nm was measured in an ELISA plate reader. Wells that developed at least 2 times the absorbance of mock-infected controls were considered positive for HAV-Bsd. Viral titers were calculated as in Figure 4.