Lipoprotein(a), an Opsonin, Enhances the Phagocytosis of Nontypeable Haemophilus influenzae by Macrophages

Figure 4

Increase in response to Lp(a) was largely inhibited by the addition of rKIV₁₀. Whether the interaction between NTHi and Lp(a) was lysine-dependent was determined by whole-cell ELISA. The mixture of Lp(a) and different concentrations of EACA (0-20 mM) and rKIV₁₀ (0.03-3 μg/mL) was used. (a) The binding of Lp(a) to intact NTHi was inhibited by two inhibitors in a dose-dependent manner. Statistical significance was determined by two-way ANOVA and the Bonferroni post hoc test. (b) Inhibition of Lp(a)-mediated phagocytosis of NTHi49247 by rKIV₁₀ was estimated by CFU counts and RFI measurements. (c) Representative photographs of rKIV₁₀- or Lp(a)-treated FITC-NTHi49247 (green) incubated with or without macrophages stained with DAPI (blue). The MOI of NTHi49247 was 56 : 1. Data are represented as from three independent experiments. Assays were conducted on at least three separate occasions. Statistical significance of the differences between groups in the phagocytosis assay was determined by two-way ANOVA and the Bonferroni post hoc test. , .

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