title: An anti-idiotype antibody which mimics the inner-core region of lipopolysaccharide protects mice against a lethal challenge with endotoxin.
abstract: Recently, we described the generation and characterization of an Armenian hamster Ab2 beta anti-idiotype monoclonal antibody (MAb4G2) specific for the binding site of a mouse monoclonal antibody, MAbY1-4A6, directed against the conserved 2-keto-3-deoxyoctulosonate (Kdo)-containing inner-core region of lipopolysaccharide (LPS) (S. K. Field, M. Pollack, and D. C. Morrison, Microb. Pathog. 15:103-120, 1993). In that study, mice and hamster immunized with MAb4G2 generated serum immunoglobulin G and M (IgG and IgM) antibodies which cross-react with Salmonella minnesota R595-chemotype rough mutant LPS (Re-LPS). In this report, we demonstrate that in C3Heb/FeJ mice, MAb4G2 elicits an immune response which is characterized by specific binding of antibody to Re-LPS, as assessed by enzyme-linked immunosorbent assay. The practical use of MAb4G2 as a potentially effective therapeutic agent against gram-negative bacterial sepsis is suggested by the demonstration that immunization of these mice with MAb4G2 results in significant protection of D-galactosamine-sensitized animals against an otherwise lethal dose of Re-LPS. Assessment of the temporal changes in Re-LPS-specific serum antibody titers from mice immunized with MAb4G2 or Re-LPS over a 40-day period indicates that immunization with Re-LPS elicits significantly higher titers of serum IgM antibodies compared with those in animals immunized with MAb4G2. Conversely, two immunizations with MAb4G2 result in an up to 10-fold increase in anti-Re-LPS-specific IgG serum antibody titers relative to those obtained in mice immunized with Re-LPS. Nineteen days after the secondary boost with MAb4G2, anti-Re-LPS-specific IgG serum antibody titers were significantly higher (three- to fourfold) compared with those in Re-LPS-treated animals. Initial immunization with the anti-idiotype antibody primes animals for enhanced secondary responses to Re-LPS, as assessed by the titers of anti-Re-LPS-specific IgG profiles. These data suggest the potential utility of MAb4G2 as a candidate vaccine against the lethal properties of gram-negative bacterial LPS.
authors.affiliation: Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City 66160.
authors.forename: S K
authors.initials: SK
authors.lastname: Field
authors.forename: D C
authors.initials: DC
authors.lastname: Morrison
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000097:blood; D000911:Antibodies, Monoclonal / Q000276:immunology*; D005260:Female; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008070:Lipopolysaccharides / Q000276:immunology* / Q000633:toxicity; D051379:Mice; D008809:Mice, Inbred C3H
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008070:Lipopolysaccharides