Fig. 5: Complement activating monoclonal antibodies promote phagocytosis and killing of K. pneumoniae by neutrophils. | Nature Communications

Fig. 5: Complement activating monoclonal antibodies promote phagocytosis and killing of K. pneumoniae by neutrophils.

From: Agnostic B cell selection approach identifies antibodies against K. pneumoniae that synergistically drive complement activation

Fig. 5

Antibody-dependent phagocytosis of K. pneumoniae KpnO2 (a) and KpnO1 (b). GFP expressing bacteria were incubated in the presence of antibody and 3% ∆NHS (KpnO2) or 0.5% ∆NHS (KpnO1) as a source of complement. Isolated human neutrophils were allowed to phagocytose opsonized bacteria for 15 min at 37 °C, after which the percentage of GFP-positive neutrophils was determined by flow cytometry. Neutrophil killing of K. pneumoniae KpnO2 (c) or KpnO1 (d). Bacteria (2 × 105 bacteria/ml) were incubated with antibodies and 8% KpnO2∆NHS or 1% KpnO1∆NHS. To this mixture 2 × 106 neutrophils/ml were added for 3 h at 37 °C. Samples were serially diluted to determine CFU/ml. The data are depicted as relative survival by dividing the CFU/ml values by the no antibody control. a–d Data represent mean ± SD of three independent experiments. c, d Data were analyzed by one-way ANOVA with Dunnett multiple comparison analysis compared to without mAb control. Significant differences are indicated, *p < 0.05, **p < 0.01 and ***p < 0.001.

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