Poly-γ-D-glutamic acid capsule (γDPGA)

The poly-γ-D-glutamic acid (γDPGA) capsule is an essential virulence factor of Bacillus anthracis, the causative agent of anthrax. Unlike most bacterial capsules which are composed of polysaccharides, the B. anthracis capsule is a homopolymer of D-glutamic acid residues linked via γ-peptide bonds (PMID: 15557061). This unique chemical structure renders the bacterium poorly immunogenic and highly resistant to phagocytosis by host immune cells such as macrophages and neutrophils (PMID: 12660289). By shielding the vegetative cells from complement-mediated killing and opsonization, the capsule enables the pathogen to proliferate rapidly within the host bloodstream and tissues. While current clinical treatments for anthrax often focus on neutralizing toxins like Protective Antigen, the γDPGA capsule is a critical target for the development of conjugate vaccines and passive immunotherapies (PMID: 19126565). Experimental monoclonal antibodies targeting the capsule have demonstrated the ability to promote opsonophagocytosis and provide protection in animal models of infection (PMID: 21606145).

Other names

Poly-D-glutamic acidPDGAγ-DPGAAnthrax capsulePoly-gamma-D-glutamic acid

Enhancement of opsonophagocytosis and neutralization of anti-phagocytic properties