Scaled Bayes factors for CAP256. Neutralization titers were strongly associated with sites 166 and 169 when the ConC reference sequence was used. These sites have previously been shown to contribute significantly to the epitope targeted by CAP256 antibodies . Shaded regions indicate the degree of evidence for an association with ID50: white indicates no or negligible evidence, light grey indicates moderate evidence and dark grey indicates strong evidence . Sites that were strongly associated with ID50 are annotated with their HXB2 position and the amino acid found to be enriched among sensitive (high titer) viruses at that site.