Figure 5. Neutralization sensitivity of envelope variants for maternal plasma.

(A) Comparison of neutralization IC₅₀ of maternal (○) and infant (Δ) variants bearing patient-derived Env V1-V5 region for each transmission pair. The baseline maternal plasma was tested at a starting dilution of 1: 50 as indicated by the dashed horizontal line. The luciferase activity obtained for each virus in the absence of serum was set to 100 %, and the neutralization of the test plasma was calculated relative to this value. The IC₅₀ was defined as the dilution of plasma that causes 50% inhibition of virus infection. The horizontal bars indicate the median IC₅₀ value for each individual. (B) Comparison of IC₅₀ between the mother (○) and infant (Δ) variants. The P value of the comparison is shown. The horizontal bars indicate the median IC₅₀ value. The dashed horizontal line indicates the lowest dilution tested.