Open AccessImmunological characterization of Rhizobium leguminosarum outer membrane antigens by use of polyclonal and monoclonal antibodies
Author(s) -
Ruud A. de Maagd,
Roel de Rijk,
Ine H. M. Mulders,
Ben Lugtenberg
Publication year - 1989
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.171.2.1136-1142.1989
Subject(s) - biology , antigen , polyclonal antibodies , antigenicity , monoclonal antibody , antiserum , bacterial outer membrane , antibody , microbiology and biotechnology , epitope , rhizobium leguminosarum , bacteria , biochemistry , rhizobiaceae , immunology , escherichia coli , genetics , symbiosis , gene
Surface antigens of Rhizobium leguminosarum biovar viciae strain 248 were characterized by using polyclonal and monoclonal antibodies. With Western immunoblotting as the criterion, an antiserum raised against living whole cells recognized mainly flagellar antigens and the O-antigen-containing part of the lipopolysaccharide (LPS). Immunization of mice with a peptidoglycan-outer membrane complex yielded eight monoclonal antibodies, of which three reacted with LPS and five reacted with various sets of outer membrane protein antigens. The observation that individual monoclonal antibodies react with sets of related proteins is discussed. Studies of the influence of calcium deficiency and LPS alterations on surface antigenicity showed that in normally grown wild-type cells, the O-antigenic side chain of LPS blocks binding of an antibody to a deeper-lying antigen. This antigen is accessible to antibodies in cells grown under calcium limitation as well as in O-antigen-lacking mutant cells. Two of the antigen groups which can be distinguished in cell envelopes of free-living bacteria were depleted in cell envelopes of isolated bacteroids, indicating that the monoclonal antibodies could be useful tools for studying the differentiation process from free-living bacteria to bacteroids.