title: Isolation of cell surface antigen mutants of Myxococcus xanthus by use of monoclonal antibodies.
abstract: Monoclonal antibodies (MAbs) with affinities for molecules on the cell surface of the procaryote Myxococcus xanthus were used in a screening strategy for the isolation of mutants lacking particular cell surface molecules. From a large library of independent mutants created by Tn5 transposon mutagenesis, mutants were isolated which lacked reactivities with MAb 1604 (a MAb specific for a cell surface protein) and MAbs 2600, 1733, 1514, 1412, and 783 (MAbs specific for carbohydrate epitopes on the O antigen of lipopolysaccharide [LPS]). The defect in antibody recognition was shown by genetic crosses and DNA hybridization experiments to be caused by the Tn5 transposon acting as a mutation at a single locus. Quantitative enzyme-linked immunosorbent assays showed that particular mutant strains had no detectable affinity for the specific MAb probe. LPS mutants were resistant to myxophage Mx8, and this provided a selection method for isolating a large number of new LPS mutants. A class of Mx8-resistant mutants lacked reactivity with MAb 1514 and therefore was defective in the O antigen of LPS. A class of Mx1-resistant mutants lacked reactivity with MAb 2254, a MAb specific for a carbohydrate epitope on the core of LPS. A comparison of MAb binding to different mutant strains revealed a principle for mapping epitopes and showed that MAbs 1514 and 2254 recognize side-chain carbohydrates rather than backbone carbohydrates within the LPS molecule.
authors.affiliation: Department of Microbiology, University of Minnesota Medical School, Minneapolis 55455.
authors.forename: J M
authors.initials: JM
authors.lastname: Fink
authors.forename: M
authors.initials: M
authors.lastname: Kalos
authors.forename: J F
authors.initials: JF
authors.lastname: Zissler
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology*; D004251:DNA Transposable Elements; D015151:Immunoblotting; D009154:Mutation; D009231:Myxococcales / Q000235:genetics / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D004251:DNA Transposable Elements