Specificity of HMAF antibodies. Stock virus samples containing only DENV2 (left panel) or DENV4 (right panel) were serially diluted and infected on C6/36 cell monolayers at 80–90% confluence in 24-well plates. The two most dilute infections of the ten-fold dilution series are shown. Infections were done in duplicate. Plates were incubated at 32°C, 5% CO2, and 88% RH. For staining, DENV2 and DENV4 samples were each incubated with both HMAF antibodies in separate wells (HMAF4: left columns of each panel, HMAF2: right columns of each panel). The antibody dilutions, which were determined to be specific and thus were used throughout the study, are shown.