Bactericidal but not nonbactericidal C5b-9 is associated with distinctive outer membrane proteins in Neisseria gonorrhoeae.
In this study, we examined the bacterial constituents associated with the complement C5b-9 complex in detergent extracts from serum-treated Neisseria gonorrhoeae (GC). 125I surface-labeled GC were incubated in 10% serum, were washed, and were solubilized in the zwitterionic sulfobetaine detergent SB12. Immunoprecipitation of 125I-GC from the extract with anti-C5 Sepharose was followed by 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiography of immunoprecipitated material. Polyacrylamide gel analysis of surface-labeled 125I-GC showed prominent bands for proteins I and III for both serum-resistant GC strain 6305 and serum-sensitive GC strain 7189. These same bands were visible with similar intensity in the SB12 extracts from presensitized and non-presensitized 6305 and 7189 after serum incubation. For those organisms bearing bactericidal C5b-9 (6305 + IgG and 7189 +/- IgG), additional distinctive bands immunoprecipitated with antibody to C5 Sepharose. These components were of 93,000, 44,000 40,000, and 15,000 daltons for 6305 + IgG, and were of 90,000, 50,000, 44,000, and 19,000 daltons for 7189 +/- IgG. Nonbactericidal C5b-9 extracted from the surface of 6305 incubated in serum, but not sensitized with antibody, was not associated with these distinctive proteins. However, this nonbactericidal C5b-9 did have a different pattern of associated bacterial surface constituents from that observed in control samples incubated with antibody to human serum albumin, which were similar to those with nonserum-incubated organisms. These studies support our earlier experiments which demonstrated that C5b-9 is in a different molecular configuration on the surface of serum-resistant GC from that on the surface of serum-sensitive GC or resistant GC rendered sensitive with bactericidal antibody.
D000818:Animals; D000937:Antigen-Antibody Reactions; D001345:Autoradiography; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis / Q000276:immunology*; D001770:Blood Bactericidal Activity; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008970:Molecular Weight; D009344:Neisseria gonorrhoeae / Q000276:immunology* / Q000378:metabolism; D011233:Precipitin Tests; D000644:Quaternary Ammonium Compounds; D011817:Rabbits
D001425:Bacterial Outer Membrane Proteins; D015938:Complement Membrane Attack Complex; D000644:Quaternary Ammonium Compounds; C034730:zwittergent 3-12; D003165:Complement System Proteins