Figure 4.

Isotyping of anti-SGS human host plasma antibodies. For each k-means cluster, six plasmas most representative of that k-means cluster immunoreactivity profile and plasmas from individuals residing in each of the Middle Eastern regions were isotyped for total anti-SGS antibodies using custom indirect ELISA. Individual donor results for each antibody isotype may be found in Supplemental Figure 5. *Clusters are like those clusters described in Table 4. †Anti-SGS antibody concentrations were assessed by secondary antibody detection of a known concentration of purified Ig isotype standards, plated in dilution series as primary antigen, and fitted to the resultant standard curve; final values were averaged per cluster across all regional donors.