Indirect ELISA demonstrating complement binding to
Klebsiella pneumoniae. Binding of C3/C3b (A, B and C) and C5–9 (D, E and F) to hypermucoviscous isolates K1 (A and D, black bars), K5 (B and E, diagonal lines), and non- hypermucoviscous (NHM) (C and F, white bars) Klebsiella pneumoniae using serum obtained from seropositive and seronegative African green monkey was estimated by optical density measured with a SpectraMax M2/M2e Microplate Reader (Molecular Devices, Sunnyvale, CA, USA). The error bars represent standard errors for triplicate samples, and the results shown are representative of three independent experiments. Asterisk indicates significant difference between treatments, p ≤ 0.05; Double asterisk indicates significant difference between treatments, p ≤ 0.001; Equal to indicates similarity between treatments, p > 0.05.