Comparison of the antibody response to bee venom phospholipase A2 induced by natural exposure in humans or by immunization in mice

Abstract

Two human and twelve murine monoclonal antibodies directed against the main bee venom allergen phospholipase A2 (PLA) were evaluated for their fine specificity of binding to antigen and their ability to inhibit the enzymatic activity of the antigen. Antibodies were induced by natural exposure of beekeepers to bee venom or immunization of mice via different methods. Both human monoclonal antibodies (hmAbs) were previously shown to recognize the native three-dimensional conformation of PLA and are directed against discontinuous epitopes which include lysine residue at position 25 as a contact residue. In contrast, six of the murine monoclonal antibodies (mmAbs) bind to the denatured structure of the protein as determined by enzyme-linked immunosorbent assay. The epitopes recognized are located near the C-terminal end (n = 8), in the centre of the polypeptide (n = 1), near the N-terminal end (n = 1) or include the carbohydrate part (n = 2) of the PLA molecule. The capacity of the antibodies to modify the enzymatic activity was also determined. The hmAbs significantly inhibit the enzyme (70-79%), whereas the mmAbs produced various degrees of inhibition (39-100%). Since the X-ray structure of PLA is known, the epitopes can be visualized in the context of the three-dimensional structure of the antigen. A qualitative correlation was found between the location of epitopes and the inhibition pattern. Strong inhibition was seen with those antibodies that recognize epitopes that lie on the surface of the enzyme that is thought to contact the phospholipid bilayer. The results show that even though both hmAbs and most mmAbs inhibit the enzymatic activity of PLA, the antigen-binding properties of antibodies from different species raised after different routes of immunization differ significantly. Thus, detailed epitope mapping studies using murine antibodies prepared by artificial immunization may have limited value in predicting epitope patterns relevant to an antibody response to allergens in humans naturally exposed to antigen/allergen.

Conformation-dependent antibody response to Pseudomonas aeruginosa outer membrane proteins induced by immunization in humans

“…The di¡erences in epitope speci¢city of antibodies induced by immunization have been reported. Schneider et al [7,8] showed that human monoclonal antibodies (mAbs) and polyclonal antibodies induced by natural exposure of beekeepers to PLA had a restricted epitope recognition in the context of an antigen with native-like structure. In contrast, mouse mAbs induced by arti¢cial immunization with recombinant PLA were heterogeneous in their epitope recognition patterns, i.e.…”

Conformation-dependent antibody response toPseudomonas aeruginosaouter membrane proteins induced by immunization in humans

“…The differences in epitope specificity of antibodies induced by immunization have been reported. Schneider et al [7,8] showed that human monoclonal antibodies (mAbs) and polyclonal antibodies induced by natural exposure of beekeepers to PLA had a restricted epitope recognition in the context of an antigen with native‐like structure. In contrast, mouse mAbs induced by artificial immunization with recombinant PLA were heterogeneous in their epitope recognition patterns, i.e.…”

Potential and limitations of epitope mapping and molecular targeting in Hymenoptera venom allergy

“…Duddler et al (41) demonstrated by site-directed mutagenesis that lysine residues, especially at position 25, abrogate binding to both mabs, indicating that this epitope probably represents the major antigenic region of B cells. Three years later, the same group demonstrated that mouse mabs, derived from B-cell clones generated by PLA2 immunization, recognized linear and carbohydrate-associated epitopes, which differ from the previously described human mab (32). In this regard, the authors suggested that the epitopes recognized by antibodies generated by artificial sensitization in other species could differ from those recognized by human antibodies, leading to a misinterpretation of the relevant allergen epitopes.…”

“…Apis melifera H-thymidine Proliferation (24,27,28,30,33,35,36), purified MHC competitive fluorescence (26,34,38,39) cytokine release: IL-2 (24,27,37), IFN-γ (24,25), IL-4 (24, 25), IL-5 (24,25), IL-10 (25) and IL-13 (24,25), biological activity antibody help (25) and neutralization (32), ELISA (29, 32), in vivo assay decreased disease (24,(28)(29)(30)40), Immunodot to sIgE (31) mice (27,32,35,37) and human (23-26, 28-31, 33, 34, 36, 38, 39) discontinuous-1 (32,41) ELISA and inhibition by antigen-qualitative binding human non peptidic-2. (42)(43)(44)(45)(46) ELISA (43,44,46), Western blot (43)(44)(45) and inhibition by antigen (42,43,46...…”

“…Monoclonal antibodies (mabs) derived from antigen-specific Bcell clones from HBV-sensitized individuals (32,41,70) or induced by immunization of experimental models (32,70) allowed the identification of discontinuous antigenic determinants presented on the Api m 1 allergen. Schneider et al (70) described a conformational epitope identified by two IgG4 mabs produced by hybridomas derived from mononuclear cells of a beekeeper.…”