title: Staphylococcal alpha-toxin: a structure-function study using a monoclonal antibody.
abstract: A monoclonal antibody (A-Tox-653.1) selected for its reactivity in a dot immunoblot assay with denatured staphylococcal alpha-toxin has been isolated and its capacity to block the hemolytic and lethal activities of alpha-toxin measured. In addition, 'reactivity with monomer, hexamer, 125I-monoiodinated and CNBr peptides of alpha-toxin was studied. In all cases the reactions of the monoclonal antibody were compared to those obtained with anti-alpha-toxin rabbit hyperimmune serum. We find that while both the monoclonal antibody and the rabbit antiserum react with all forms of alpha-toxin, only the rabbit antiserum blocks hemolytic or lethal activity. Further, the rabbit antiserum reacts with CNBr fragments IV, V ad VII, whereas the monoclonal antibody reacts only with the carboxy terminal CNBr peptide VII. We conclude that, in solution, the carboxy terminal segment of alpha-toxin is relatively free and reaction with the monoclonal antibody neither impedes its binding to the specific receptor on the membrane nor interferes with formation of the hexamer complex.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins / Q000276:immunology*; D003101:Collodion; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D006460:Hemolysin Proteins; D006461:Hemolysis; D005779:Immunodiffusion; D051379:Mice; D008807:Mice, Inbred BALB C; D010446:Peptide Fragments / Q000276:immunology; D011817:Rabbits
chemical_list: D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins; D000939:Epitopes; D006460:Hemolysin Proteins; D010446:Peptide Fragments; C021091:staphylococcal alpha-toxin; D003101:Collodion; D003488:Cyanogen Bromide