title: Stereo-selective binding of monoclonal antibodies to the poly-γ-D-glutamic acid capsular antigen of Bacillus anthracis.
abstract: Bacillus anthracis is surrounded by an anti-phagocytic capsule that is entirely composed of γ-linked D-glutamic acid (γDPGA). γDPGA is required for virulence and is produced in large quantities following spore germination. We have previously described the isolation of several γDPGA-reactive mAbs. The reagents are effective in both immunoprotection and diagnostic applications. The current work was done to further investigate the specificity of γDPGA-reactive mAbs. The specificity of each mAb was characterized using surface plasmon resonance. Our results indicate that each mAb is stereoselective for binding to D-glutamic acid oligomers, but to varying degrees. In particular, mAb F26G3 is highly selective for γDPGA; alterations in stereochemistry disrupted recognition. These differences in mAb reactivity suggest that binding of γDPGA by mAb F26G3 is more specific than non-directional ionic interactions between a negatively charged antigen and a positively charged antibody.
authors.affiliation: Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, NV 89557, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hubbard
authors.forename: Peter
authors.initials: P
authors.lastname: Thorkildson
authors.forename: William H
authors.initials: WH
authors.lastname: Welch
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Kozel
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism*; D000915:Antibody Affinity; D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions; D000942:Antigens, Bacterial / Q000737:chemistry*; D001408:Bacillus anthracis / Q000737:chemistry / Q000276:immunology*; D016667:Bacterial Capsules / Q000737:chemistry / Q000276:immunology*; D051379:Mice; D018448:Models, Immunological; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000276:immunology; D013237:Stereoisomerism
chemical_list: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid