Characterization of the 35-kilodalton Treponema pallidum subsp. pallidum recombinant lipoprotein TmpC and antibody response to lipidated and nonlipidated T. pallidum antigens
| Autor: | Leo M. Schouls, J. D. A. Van Embden, H. G. J. Van Der Heide |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Antigenicity
Lipoproteins Molecular Sequence Data Immunology Biology Microbiology law.invention Plasmid Antigen law Humans Amino Acid Sequence Syphilis Treponema pallidum Peptide sequence Antigens Bacterial Treponema Base Sequence Immunogenicity Membrane Proteins biology.organism_classification Antibodies Bacterial Lipids Molecular biology Recombinant Proteins Infectious Diseases biology.protein Recombinant DNA Parasitology Antibody Protein Processing Post-Translational Research Article |
| Zdroj: | Infection and Immunity. 59:3536-3546 |
| ISSN: | 1098-5522 0019-9567 |
| DOI: | 10.1128/iai.59.10.3536-3546.1991 |
| Popis: | Thegeneencoding the35-kDa immunogenic Treponema pallidum subsp. pallidum (T.pallidum) membrane protein C,TmpC,wascloned, sequenced, andexpressed inEscherichia coli. Thededuced aminoacid sequence carries an N-terminal signal sequencewitha four-amino-acid motif, whichischaracteristic forbacterial lipoproteins. Metabolic labeling withradioactive palmitic acidofE.coli expressing TmpCrevealed incorporation ofthefatty acid into theantigen. Theantigen wasoverproduced, purified tonearhomogeneity andused inan enzyme-linked immunosorbent assay(ELISA) toevaluate itspotential fortheserodiagnosis ofsyphilis. Although all serafromuntreated secondary syphilis patients were reactive inthis TmpC ELISA,only a minority oftheserum samples fromuntreated patients intheprimary orearly latent stage ofthedisease contained significant anti-TmpC antibodies. Tostudy theinfluence ofthelipid moiety on theantigenic properties oftheTmpC,TmpA,andTpDlipoproteins, plasmids encoding nonlipidated forms ofthese antigens were constructed. Inaddition, a plasmid expressing a lipidated formoftheotherwise non-lipid-modified antigen TmpBwas constructed. Immunization andabsorption experiments withthese lipidated andnonlipidatedantigens showedthatantibodies against thelipid moiety oflipoproteins couldnotbedetected on immunoblots, neither inserafrominfected rabbits norinserafromanimals immunized withthelipoproteins. Inaddition, we were unable todemonstrate cross-reactivity between antibodies against theT.pallidum lipoproteins andthose reactive totheVenereal Diseases Research Laboratories test, suggesting thatantibodies reactive totheVenereal Diseases Research Laboratories test areunrelated toantilipoprotein antibodies. Infection withTreponema pallidum subsp. pallidum (T. pallidum), thecausative agentofsyphilis, leads toa powerfulcellular andhumoral immuneresponse.Despite this vigorous immuneresponse,T.pallidum isnotfully eliminated, as manifested byrelapses ofsecondary syphilis and/or late syphilitic processes.A possible explanation for this incomplete clearance ofT.pallidum may bethenear lackofantibody binding tothesurface ofthetreponemes. Theinaccessibility toantibodies hasbeenappreciated since thestudies ofHardyandNellin1957on thenonagglutinability withanti-T. pallidum antibodies offreshly isolated treponemes (8). Theability ofT.pallidum cells tobind a large variety ofhostproteins (1)ispresumed tocontribute to this inaccessibility toantibodies. Studies on thestructure ofthesurface ofT.pallidum have beengreatly hindered bytheinability tocultivate theorganismandtoseparate theouterandinner membranes. However,theextraction ofT.pallidum withlowconcentrations ofdetergents like sodiumdodecyl sulfate (SDS)andTriton X-114suggests thattheoutermembrane contains a paucity ofproteins (22). Thisisconsistent withrecentobservations on freeze-fractured T.pallidum cells whichsuggest an unusually lowdensity ofintramembranous particles inthe outermembrane (24, 33). Although no direct data areavailable on thestructure oftheoutersurface ofT.pallidum, the apparent paucity ofproteins likely contributes totherelative inaccessibility ofT.pallidum toantibodies. Another unusual property ofT.pallidum istheposttranslational lipidation ofmany ofthemajorimmunogenic mem |
| Databáze: | OpenAIRE |
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