FIG. 2.

Heat map and clustering analysis of serum. ID₅₀ values of 103 sera against 20 isolates are shown. Each row of the heat map shows ID₅₀ values for a single serum, and columns show virus isolates. Darker colors represent stronger neutralization (see key). The vertical order of sera is based on geometric mean titer; placement of clusters within this ranking uses the mean titer for all cluster members. The bars labeled “Bootstrap” or “Noise” show the results of statistical analysis of clustering. Both are visualized by mixing red, yellow, and blue corresponding to the relative frequencies of matched group assignments. A bright red, yellow, or blue color is a categorization that is unambiguous. Sera or isolates are grouped if they have a categorization of 90% or greater consistency by both the bootstrap and noise tests. Boxes highlight the clusters. Sera in red type are from LTNP. Clusters of patient sera are labeled P1, P2, and P3, while clusters of isolates are labeled I1, I2, and I3.