Figure 5.

Improved sensitivity of gH-specific ASC through affinity capture of coating antigen. PBMC were stimulated in vitro and evaluated for antibody-secreting (ASC) reactivity against the gH pentamer complex protein from HCMV. (A) Representative wells images depicting antigen-specific IgG⁺ ASC in wells coated directly with 10 μg/mL of gH pentamer complex protein, or through affinity capture using the genetically encoded hexahistidine (6XHis) tag. Magnification and contrast enhancements were uniformly performed on all images to aid their visualization in publication. (B) gH-specific FluoroSpots were merged into FCS files and visualized as bivariate plots. FluoroSpots originating from assay wells in which gH pentamer complex was directly captured on the membrane (black dots) or through affinity capture (red) are shown as overlays. The combined number of FluoroSpots detected in replicate wells for each of the respective donors is indicated in the inset using the same red/black color code.