Specific binding of serum antibodies to the capsule of Spn10A. (A) Representative confocal images (left) and quantitative analysis (right) showing mouse primary KCs binding with Spn10A. The KCs were incubated with TH860^10A supplemented with or without 10% serum, and 100 μg/ml CPS10A or CPS10A∆wcrG. Scale bar, 10 μm. n = 6. (B) Schematic illustration of the strategy for screening CPS10A-binding proteins. (C) Plot of proteins significantly enriched by CPS10A-coated beads. The top six enriched proteins compared with that of CPS10A∆wcrG-coated beads are labeled in red. n = 3. The detailed results are listed in Table S1. (D) ELISA detection of IgG and IgM to CPS10A or CPS10A∆wcrG in WT mouse serum. n = 3. (E) Flow cytometry detection of the IgG and IgM deposition on the surface of TH860^10A or TH860^10A∆wcrG incubated with mouse serum. (F) ELISA detection of IgG and IgM to CPS10A or CPS10A∆wcrG in sera of 2-mo-old children. n = 18. Data were representative results (A and D–F) or pooled from three independent experiments (C). Ordinary two-way ANOVA with Sidak’s multiple comparisons test (A and D) and paired t test (F) were performed. ***, P < 0.001; ****, P < 0.0001; ns, not significant.