title: Multimeric C9 within C5b-9 deposits in unique locations in the cell wall of Salmonella typhimurium.
abstract: We have shown previously that multimeric C9 within C5b-9 (C9:C5b-8 greater than 3:1) is needed for killing of a rough strain of Escherichia coli. We now extend these studies using serum sensitive, rough (R) and serum resistant, wild type (WT) strains of Salmonella typhimurium as well as a mutant S. typhimurium strain (TS) with a temperature sensitive mutation in synthesis of keto-deoxy-octulosonate, a constituent within the deep core structure of Salmonella LPS. Both R and TS required multimeric C9 within C5b-9 to be killed. Addition at 37 degrees C of increasing inputs of C9 to TS or R bearing C5b-9 led to a dose-related increase in C9 binding and killing. In contrast, addition of high inputs of C9 to the same strains at 4 degrees C, a procedure that limits the C9:C5b-8 ratio to 1:1, resulted in low C9 binding and minimal killing. Bactericidal C5b-9 formed at 37 degrees C on R and TS with high inputs of C9 co-sedimented with the bacterial outer membrane on sucrose density gradient analysis. Non-bactericidal C5b-9 on R, WT, and TS co-sedimented near the inner membrane, despite the presumed lack of association between these constituents. Whereas 125I C9 within the non-bactericidal pools immunoprecipitate with anti-C5, 125I C9 within bactericidal pools did not immunoprecipitate with anti-C5, anti-C7, or anti-C9. These findings suggest that bactericidal C5b-9 may be deposited in a unique location or configuration within the bacterial cell wall.
authors.affiliation: Laboratory of Parasitic Disease, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892.
authors.forename: K A
authors.initials: KA
authors.lastname: Joiner
authors.forename: A B
authors.initials: AB
authors.lastname: Tartanian
authors.forename: C H
authors.initials: CH
authors.lastname: Hammer
authors.forename: J E
authors.initials: JE
authors.lastname: Schweinle
mesh_terms: D002473:Cell Wall / Q000276:immunology / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D003182:Complement C5 / Q000276:immunology; D003185:Complement C8 / Q000378:metabolism; D003186:Complement C9 / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D003602:Cytotoxicity, Immunologic; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007106:Immune Sera; D007457:Iodine Radioisotopes; D046911:Macromolecular Substances; D011233:Precipitin Tests; D011951:Receptors, Complement / Q000502:physiology; D012486:Salmonella typhimurium / Q000276:immunology / Q000378:metabolism*; D013696:Temperature
chemical_list: D003182:Complement C5; D003185:Complement C8; D003186:Complement C9; D015938:Complement Membrane Attack Complex; D007106:Immune Sera; D007457:Iodine Radioisotopes; D046911:Macromolecular Substances; D011951:Receptors, Complement; D003165:Complement System Proteins