Figure 3.

OPK of K. pneumoniae by macrophages in the presence of carbohydrate binding antibodies, measured by release of luciferase. a) Killing of K. pneumoniae 43816 ΔcpsB lux by primary human macrophages in the presence of IgGs. Bacteria, IgGs and complement were added to plates containing macrophages and incubated for 5 hours. Luminescence was measured using an Envision multilabel plate reader (PerkinElmer). Control = negative isotype control. Killing by test IgG or control IgG was calculated as a percentage of wells containing no IgG using the following calculation: (IgG treatment/no IgG)*100. Error bars represent 1 SD. N = 3 individual macrophage donors. b) Killing of K. pneumoniae 43816 ΔcpsB lux by primary human macrophages in the presence of IgGs, with (red) and without (blue) complement. c) EC₅₀ values for IgG treatment in the presence and absence of complement