%0 Journal Article %1 vogel_complement_1997 %A Vogel, U %A Weinberger, A %A Frank, R %A Müller, A %A Köhl, J %A Atkinson, J P %A Frosch, M %D 1997 %J Infection and Immunity %K Acid, Activity, Bacterial Bactericidal Blood C3, C3b, Capsules, Complement Humans, Lipopolysaccharides, Mutation, Neisseria Sialyltransferases, meningitidis, serum_resistance {4-Epimerase} {N-Acetylneuraminic} {UDPglucose}, %N 10 %P 4022--4029 %T Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis %U http://www.ncbi.nlm.nih.gov/pubmed/9317002 %V 65 %X Serogroup B meningococci express sialic acids on their surfaces as a modification of the lipooligosaccharide (LOS) and as capsular material consisting of alpha2,8-linked sialic acid homopolymers. The aim of this study was to elucidate the impact of each sialic acid component on the deposition of complement factor C3 and serum resistance. For this purpose, we used isogenic mutants deficient in capsule expression (a polysialyltransferase mutant) or sialylation of the LOS (a galE mutant) or both (a mutant with a deletion of the cps gene locus). Bactericidal assays using 40\% normal human serum (NHS) demonstrated that both the capsule and LOS sialic acid are indispensable for serum resistance. By immunoblotting with monoclonal antibody MAb755 that is specific for the C3 alpha-chain, we were able to demonstrate that C3 from 40\% NHS was covalently linked to the surface structures of meningococci as C3b and iC3b, irrespective of the surface sialic acid compounds. However, C3b linkage was more pronounced and occurred on a larger number of target molecules in galE mutants with nonsialylated LOS than in meningococci with wild-type LOS, irrespective of the capsule phenotype. C3b deposition was caused by both the classical pathway (CP) and the alternative pathway of complement activation. Use of 10\% NHS revealed that at low serum concentrations, C3 deposition occurred via the CP and was detected primarily on nonsialylated-LOS galE mutants, irrespective of the capsular phenotype. Accordingly, immunoglobulin M (IgM) binding to meningococci from heat-inactivated NHS was demonstrated only in both encapsulated and unencapsulated galE mutants. In contrast, inhibition of IgA binding required both encapsulation and LOS sialylation. We conclude that serum resistance in wild-type serogroup B meningococci can only be partly explained by an alteration of the C3b linkage pattern, which seems to depend primarily on the presence of wild-type LOS, since a serum-resistant phenotype also requires capsule expression.

@article{vogel_complement_1997, abstract = {Serogroup B meningococci express sialic acids on their surfaces as a modification of the lipooligosaccharide {(LOS)} and as capsular material consisting of alpha2,8-linked sialic acid homopolymers. The aim of this study was to elucidate the impact of each sialic acid component on the deposition of complement factor C3 and serum resistance. For this purpose, we used isogenic mutants deficient in capsule expression (a polysialyltransferase mutant) or sialylation of the {LOS} (a {galE} mutant) or both (a mutant with a deletion of the cps gene locus). Bactericidal assays using 40\% normal human serum {(NHS)} demonstrated that both the capsule and {LOS} sialic acid are indispensable for serum resistance. By immunoblotting with monoclonal antibody {MAb755} that is specific for the C3 alpha-chain, we were able to demonstrate that C3 from 40\% {NHS} was covalently linked to the surface structures of meningococci as C3b and {iC3b}, irrespective of the surface sialic acid compounds. However, C3b linkage was more pronounced and occurred on a larger number of target molecules in {galE} mutants with nonsialylated {LOS} than in meningococci with wild-type {LOS}, irrespective of the capsule phenotype. C3b deposition was caused by both the classical pathway {(CP)} and the alternative pathway of complement activation. Use of 10\% {NHS} revealed that at low serum concentrations, C3 deposition occurred via the {CP} and was detected primarily on {nonsialylated-LOS} {galE} mutants, irrespective of the capsular phenotype. Accordingly, immunoglobulin M {(IgM)} binding to meningococci from heat-inactivated {NHS} was demonstrated only in both encapsulated and unencapsulated {galE} mutants. In contrast, inhibition of {IgA} binding required both encapsulation and {LOS} sialylation. We conclude that serum resistance in wild-type serogroup B meningococci can only be partly explained by an alteration of the C3b linkage pattern, which seems to depend primarily on the presence of wild-type {LOS}, since a serum-resistant phenotype also requires capsule expression.}, added-at = {2011-06-24T11:21:47.000+0200}, author = {Vogel, U and Weinberger, A and Frank, R and Müller, A and Köhl, J and Atkinson, J P and Frosch, M}, biburl = {https://www.bibsonomy.org/bibtex/22edb1dc9aa55635117ad13dfdd848368/ag_vogel}, interhash = {7d310d65a421f91d274ced5ac8738832}, intrahash = {2edb1dc9aa55635117ad13dfdd848368}, issn = {0019-9567}, journal = {Infection and Immunity}, keywords = {Acid, Activity, Bacterial Bactericidal Blood C3, C3b, Capsules, Complement Humans, Lipopolysaccharides, Mutation, Neisseria Sialyltransferases, meningitidis, serum_resistance {4-Epimerase} {N-Acetylneuraminic} {UDPglucose},}, month = oct, note = {{PMID:} 9317002}, number = 10, pages = {4022--4029}, timestamp = {2011-06-24T16:19:18.000+0200}, title = {Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis}, url = {http://www.ncbi.nlm.nih.gov/pubmed/9317002}, volume = 65, year = 1997 }