Molecular analysis of anti-N-propionyl Neisseria meningitidis group B polysaccharide monoclonal antibodies.
The capsular polysaccharide of Neisseria meningitidis group B (MBPS) is a polymer of alpha (2-->8) N-acetyl neuraminic acid, which is chemically identical to polysialic acid (PSA) expressed in human tissues. Antibodies from mice immunized with a MBPS-protein conjugate vaccine in which N-acetyl groups have been replaced by propionyl groups (N-Pr MBPS) can be bactericidal and show minimal or no cross-reactivity with human PSA. To investigate the molecular basis for antigen recognition, we cloned and sequenced the variable region (V) genes of five bactericidal anti-N-Pr MBPS murine mAbs and produced computer models of the combining sites. The results were compared to those reported in the literature for two autoreactive anti-MBPS. The V region genes of the anti-N-Pr MBPS mAbs and the anti-MBPS autoreactive mAbs are derived from a limited set of germline V, J, and D genes. However, the anti-N-Pr MBPS mAbs are more mutated than the anti-MBPS mAbs and the former use V-D-J editing that introduces arginine in H-CDR3. Models of the respective combining sites indicate that the anti-MBPS or anti-N-Pr MBPS mAbs that react with host PSA have relatively wide and shallow grooves with a high overall positive charge, consistent with recognition of extended helical polysaccharide structures recognized by the autoreactive mAbs. In contrast, anti-N-Pr MBPS mAbs that do not react with host PSA contain pockets and deep clefts that are consistent with recognition of discrete structural features of individual residues.
Moe
Gregory R
GR
Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, USA. gmoe@chori.org
Dave
Apurva
A
Granoff
Dan M
DM
D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000737:chemistry / Q000235:genetics*; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000235:genetics*; D000942:Antigens, Bacterial / Q000737:chemistry; D001323:Autoantibodies / Q000737:chemistry / Q000235:genetics; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics; D022401:Meningococcal Vaccines / Q000276:immunology; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D038541:Neisseria meningitidis, Serogroup B / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000276:immunology*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D012794:Sialic Acids / Q000737:chemistry / Q000276:immunology
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001323:Autoantibodies; D007135:Immunoglobulin Variable Region; D022401:Meningococcal Vaccines; D011135:Polysaccharides, Bacterial; D012794:Sialic Acids; C021319:polysialic acid