Stereo-selective binding of monoclonal antibodies to the poly-gamma-d-glutamic acid capsular antigen of Bacillus anthracis

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• 作者：Mark A. Hubbard^a ; ^c ; Peter Thorkildson^a ; William H. Welch^b ; Thomas R. Kozel^a ; ^c ; ^{tkozel@medicine.nevada.edu}
• 关键词：¦ÃDPGA ; ¦Ã-linked d-polyglutamic acid ; ¦ÃLPGA ; ¦Ã-linked l-polyglutamic acid ; mAb ; monoclonal antibody ; pAb ; polyclonal antibody ; SPR ; surface plasmon resonance ; KI ; inhibition constant ; KD ; dissociation constant
• 刊名：Molecular Immunology
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：55
• 期：3-4
• 页码：337-344
• 全文大小：1289 K

文摘

Bacillus anthracis is surrounded by an anti-phagocytic capsule that is entirely composed of ¦Ã-linked d-glutamic acid (¦ÃDPGA). ¦ÃDPGA is required for virulence and is produced in large quantities following spore germination. We have previously described the isolation of several ¦ÃDPGA-reactive mAbs. The reagents are effective in both immunoprotection and diagnostic applications. The current work was done to further investigate the specificity of ¦ÃDPGA-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 ¦ÃDPGA; alterations in stereochemistry disrupted recognition. These differences in mAb reactivity suggest that binding of ¦ÃDPGA by mAb F26G3 is more specific than non-directional ionic interactions between a negatively charged antigen and a positively charged antibody.