Fig 4.

(A) Amino acid alignment of envelope region of F535 variants. The sequence of F535 M^sens is shown. Symbols: dashes, regions in B^res that are identical to the maternal sequence shown; dots, deletions in B^res; x, loss of PNGS in B^res; +, gain of PNGS in B^res; *, shift of PNGS in B^res. Abbreviations are described in the legend to Fig. 3. (B) Neutralization profiles of F535 pseudoviruses bearing chimeric envelopes from B^res and M^sens against maternal plasma. Gray bars represent envelope sequence of M^sens. White bars represent envelope sequence of B^res. Average IC₅₀s from at least 2 independent experiments are shown. (C) Neutralization curves of chimeras bearing regions that confer neutralization resistance to maternal plasma are shown relative to native maternal and infant viruses. Percent neutralization versus plasma dilution is shown.