FIG 4.

Antibody specificity of primary and secondary flavivirus infections. Relative binding (±SEM) of convalescent-phase serum antibodies from nonhuman primate (NHP) and human flavivirus infections to 15 flavivirus E proteins is shown. (A) Sera from primary infections are indicated by color as follows: gray, DENV-challenged NHPs (individual data for each NHP group are overlaid in a scatter plot; n = 4 each for the DENV1 [black], DENV2 [green], and DENV3 [orange] groups and n = 3 for the DENV4 group [magenta]); green, human (Hu) rDEN2Δ30 (n = 8) (primary infection); red, pooled African and Asian lineage ZIKV NHPs (n = 6); white, YFV-vaccinated NHPs (n = 3). (B) Sera from confirmed human flaviviral infections with unknown infection histories are indicated by color as follows: gray, DENV (individual data are overlaid in a scatter plot; the colors correspond to the most recent DENV infection); green, DENV2 (n = 5); orange, DENV3 (n = 2); red, ZIKV (n = 4); white, YFV vaccination (n = 13); cyan, WNV (n = 20). (C) Predicted infection histories of human secondary DENV (gray in panel B) and primary ZIKV (red in panel B) infections, based on a supervised SVM classifier. Individual human sera are shown at the bottom (Z for ZIKV, D2 for DENV2, and D3 for DENV3; virus followed by serum identification [ID] number), with probability values for each viral class (left) gradient colored from low to high (white to royal blue) (right). Predicted infection histories are designated by colored bars above serum ID (DENV1 [black], DENV4 [magenta], no prediction [no bar]).