Capsule carbohydrate structure determines virulence in Acinetobacter baumannii
Fig 5
Receptor blockade with siRNA knockdown, antibody neutralization of beta-glucan receptors prior to bacterial uptake, and phagocytosis of bacteria by peritoneal macrophages and neutrophils.
(5A) RAW 264.7 cells were pre-incubated with anti-Dectin-1, anti-CR3, anti-MR neutralizing monoclonal antibodies or an isotype control prior to co-incubation with ATCC 17978. *p < 0.0005, **p < 0.0001 (5B) Knockdown of Dectin-1 and/or CR3 in RAW 264.7 cells followed by incubation with ATCC 17978. *p < 0.0001 (5C) Primary peritoneally-elicited macrophages from C57BL/6 mice followed by phagocytosis assays with ATCC 17978. *p < 0.05, **p < 0.0001 (5D) Phagocytosis assays of ATCC 17978 with peritoneal neutrophils from wild-type mice with disruption of phagocytosis upon the addition of heat-inactivated serum (HI-S) or complement-active serum (CA-S). *p < 0.0001 (5E) Phagocytosis assays with RAW 264.7 macrophages with gtr6+ and capsule-free strains (ATCC 17978 WT, 15827, ATCC 17978 ΔitrA), and gtr6- strains (ATCC 17978 Δgtr6, HUMC1), with complement active (CA-S) or heat-inactivated (HI-S) serum. *p < 0.0001. Experiments repeated once with two biological replicates. Wide bars denote median, error bars denote IQR.