Antigenic specificity and heterogeneity of lipopolysaccharides from pyocin-sensitive and -resistant strains of Neisseria gonorrhoeae

Abstract

Homologous antisera were raised against lipopolysaccharides (LPSs) isolated from pyocin 103-sensitive JW31 strain Neisseria gonorrhoeae and its isogenic, pyocin-resistant variant, JW31R. Changes in immunochemical reactivity of LPS antigen associated with pyocin-resistance were examined by enzyme-linked immunosorbent assay, employing homologous and heterologous anti-LPS immune sera. The acquisition of pyocin 103 resistance is accompanied by a loss in LPS antigen reactivity with homologous anti-LPS. The variant LPS of pyocin 103-resistant mutants is immunogenic and displays a new, distinct antigenic specificity shared with other pyocin 103-resistant variant gonococcal strains. The acquisition of pyocin 103 resistance by JW31 strain gonococci is also accompanied by a striking loss of LPS cross-reactivity with antistreptococcal polysaccharide reagents having an antibody combining site specificity directed against the chemically defined lactose polymer from Streptococcus faecalis cell wall and pneumococcal type 14 capsular polysaccharide. When examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sodium dodecyl sulfate-urea-polyacrylamide gel electrophoresis, JW31 and JW31R LPSs show banding patterns characteristic of microheterogeneous, rough-type LPS devoid of O-side chains. Immunoblot transfer analysis of gel-separated gonococcal LPS antigens shows a difference in the pattern of antibody binding by homologous versus cross-reactive anti-LPS, which suggests a heterogeneity in the distribution of cross-reactive determinants among LPS molecules.