Poly-gamma-Glutamate Capsule-Degrading Enzyme Treatment Enhances Phagocytosis and Killing of Encapsulated Bacillus Anthracis
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
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The poly gamma-D-glutamic acid capsule confers antiphagocytic properties on Bacillus anthracis and is essential for virulence. In this study, we showed that two recombinant glutamylases CapD, a gamma-polyglutamic acid depolymerase encoded on the B. anthracis capsule plasmid, and PghP, a gamma-polyglutamic acid hydrolase encoded by bacteriophage Phi, NIT1, degraded purified capsule and removed the capsule from the surface of anthrax bacilli. Treatment with CapD or PghP induced macrophage phagocytosis of encapsulated B. anthracis. Additionally, enzyme treatment enabled human neutrophils to kill encapsulated organisms. The levels of both phagocytosis and killing corresponded to the degree of capsule degradation CapD was more effective than PghP.
- Medicine and Medical Research