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Abstract
Bacterial pathogens have evolved to regulate virulence gene expression at critical points in the colonization and infection processes to successfully cause disease. The Shigella species infect the epithelial cells lining the colon to result in millions of cases of diarrhea and a significant global health burden. As antibiotic resistance rates increase, understanding the mechanisms of infection is vital to ensure successful vaccine development. Despite significant gains in our understanding of Shigella infection, it remains unknown how the bacteria initiate contact with the colonic epithelium. Most pathogens harbor multiple adherence factors to facilitate this process, but Shigella was thought to have lost the ability to produce these factors. Interestingly, we have identified conditions that mimic some features of gastrointestinal transit and that enable Shigella to express adherence structural genes. This work highlights aspects of genetic regulation for Shigella adherence factors and may have a significant impact on future vaccine development. The Shigella species are Gram-negative, facultative intracellular pathogens that invade the colonic epithelium and cause significant diarrheal disease. Despite extensive research on the pathogen, a comprehensive understanding of how Shigella initiates contact with epithelial cells remains unknown. Shigella maintains many of the same Escherichia coli adherence gene operons; however, at least one critical gene component in each operon is currently annotated as a pseudogene in reference genomes. These annotations, coupled with a lack of structures upon microscopic analysis following growth in laboratory media, have led the field to hypothesize that Shigella is unable to produce fimbriae or other traditional adherence factors. Nevertheless, our previous analyses have demonstrated that a combination of bile salts and glucose induces both biofilm formation and adherence to colonic epithelial cells. The goal of this study was to perform transcriptomic and genetic analyses to demonstrate that adherence gene operons in Shigella flexneri strain 2457T are functional, despite the gene annotations. Our results demonstrate that at least three structural genes facilitate S. flexneri 2457T adherence for epithelial cell contact and biofilm formation. Furthermore, our results demonstrate that host factors, namely, glucose and bile salts at their physiological concentrations in the small intestine, offer key environmental stimuli required for adherence factor expression in S. flexneri. This research may have a significant impact on Shigella vaccine development and further highlights the importance of utilizing in vivo-like conditions to study bacterial pathogenesis. IMPORTANCE Bacterial pathogens have evolved to regulate virulence gene expression at critical points in the colonization and infection processes to successfully cause disease. The Shigella species infect the epithelial cells lining the colon to result in millions of cases of diarrhea and a significant global health burden. As antibiotic resistance rates increase, understanding the mechanisms of infection is vital to ensure successful vaccine development. Despite significant gains in our understanding of Shigella infection, it remains unknown how the bacteria initiate contact with the colonic epithelium. Most pathogens harbor multiple adherence factors to facilitate this process, but Shigella was thought to have lost the ability to produce these factors. Interestingly, we have identified conditions that mimic some features of gastrointestinal transit and that enable Shigella to express adherence structural genes. This work highlights aspects of genetic regulation for Shigella adherence factors and may have a significant impact on future vaccine development.
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Evolutionary analysis points to divergent physiological roles of type 1 fimbriae in Salmonella and Escherichia coli. mBio 2013; 4:mBio.00625-12. [PMID: 23462115 PMCID: PMC3604780 DOI: 10.1128/mbio.00625-12] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Salmonella and Escherichia coli mannose-binding type 1 fimbriae exhibit highly similar receptor specificities, morphologies, and mechanisms of assembly but are nonorthologous in nature, i.e., not closely related evolutionarily. Their operons differ in chromosomal location, gene arrangement, and regulatory components. In the current study, we performed a comparative genetic and structural analysis of the major structural subunit, FimA, from Salmonella and E. coli and found that FimA pilins undergo diverse evolutionary adaptation in the different species. Whereas the E. coli fimA locus is characterized by high allelic diversity, frequent intragenic recombination, and horizontal movement, Salmonella fimA shows structural diversity that is more than 5-fold lower without strong evidence of gene shuffling or homologous recombination. In contrast to Salmonella FimA, the amino acid substitutions in the E. coli pilin heavily target the protein regions that are predicted to be exposed on the external surface of fimbriae. Altogether, our results suggest that E. coli, but not Salmonella, type 1 fimbriae display a high level of structural diversity consistent with a strong selection for antigenic variation under immune pressure. Thus, type 1 fimbriae in these closely related bacterial species appear to function in distinctly different physiological environments. IMPORTANCE E. coli and Salmonella are enteric bacteria that are closely related from an evolutionary perspective. They are both notorious human pathogens, though with somewhat distinct ecologies and virulence mechanisms. Type 1 fimbriae are rod-shaped surface appendages found in most E. coli and Salmonella isolates. In both species, they mediate bacterial adhesion to mannose receptors on host cells and share essentially the same morphology and assembly mechanisms. Here we show that despite the strong resemblances in function and structure, they are exposed to very different natural selection environments. Sequence analysis indicates that E. coli, but not Salmonella, fimbriae are subjected to strong immune pressure, resulting in a high level of major fimbrial protein gene shuffling and interbacterial transfer. Thus, evolutionary analysis tools can provide evidence of divergent physiological roles of functionally similar traits in different bacterial species.
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3
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McClain MS, Blomfield IC, Eberhardt KJ, Eisenstein BI. Inversion-independent phase variation of type 1 fimbriae in Escherichia coli. J Bacteriol 1993; 175:4335-44. [PMID: 8101185 PMCID: PMC204873 DOI: 10.1128/jb.175.14.4335-4344.1993] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The roles of fimB and fimE in the phase-variable expression of type 1 fimbriae in Escherichia coli were examined. A method was developed to study the effects of fimB and fimE on both recombination of the fim invertible element and fimbrial expression. The method used an allelic exchange procedure consisting of two steps. The first step, construction of intermediate strains, deleted fimB and fimE. This step locked the invertible element in either the on or the off orientation. The second step of the exchange procedure introduced either wild-type or mutant alleles of fimB and/or fimE into the chromosome of the intermediate strains. Analysis of the resulting strains supported the current, plasmid-based model of recombination. Unexpectedly, strains in which the invertible element was locked in the on orientation (either by mutation of both fimB and fimE or, in a control strain, by mutation of the left inverted repeat sequence of the invertible element) continued to exhibit phase-variable expression of type 1 fimbriae. A strain in which fimA was transcribed from the tac promoter continued to exhibit phase-variable fimbrial expression, suggesting that inversion-independent phase variation cannot be explained by variable transcription initiation of fimA.
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MESH Headings
- Alleles
- Bacterial Proteins/biosynthesis
- Bacterial Proteins/genetics
- Base Sequence
- Chromosome Inversion
- Cloning, Molecular
- DNA, Bacterial/genetics
- DNA, Bacterial/metabolism
- DNA, Recombinant/metabolism
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/genetics
- Escherichia coli/genetics
- Escherichia coli/growth & development
- Escherichia coli/physiology
- Escherichia coli/ultrastructure
- Escherichia coli Proteins
- Fimbriae Proteins
- Fimbriae, Bacterial/physiology
- Fimbriae, Bacterial/ultrastructure
- Gene Expression
- Genes, Bacterial
- Integrases
- Microscopy, Electron
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Transcription, Genetic
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Affiliation(s)
- M S McClain
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109-0620
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4
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Dal Nogare AR, Azizi SQ. Chinese hamster ovarian cell glycoproteins that mediate type 1 piliated gram-negative bacterial adherence. Am J Respir Cell Mol Biol 1992; 7:399-405. [PMID: 1356377 DOI: 10.1165/ajrcmb/7.4.399] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We used Chinese hamster ovary (CHO) cell lines to define the structures of glycoproteins responsible for Type 1 piliated bacterial adherence. CSH 50 Escherichia coli, a Type 1 piliated bacteria, adhered significantly better than an isogenic nonpiliated E. coli to all CHO lines tested. CSH 50 E. coli adhered least well to CHO cells expressing intact complex type oligosaccharides on cell surface glycoproteins. CSH 50 adherence increased when shorter oligosaccharides were present and was maximal when mannose groups were present in terminal, nonreducing positions. Five high mannose type glycoproteins, with molecular weights of 79, 75, 55, 50, and 37 kD, were identified as high affinity ligands for Type 1 piliated bacteria. Our results suggest that alterations in cell surface carbohydrates may increase adherence of Type 1 piliated gram-negative bacteria to cells.
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Affiliation(s)
- A R Dal Nogare
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-9034
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5
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Blomfield IC, McClain MS, Princ JA, Calie PJ, Eisenstein BI. Type 1 fimbriation and fimE mutants of Escherichia coli K-12. J Bacteriol 1991; 173:5298-307. [PMID: 1679429 PMCID: PMC208239 DOI: 10.1128/jb.173.17.5298-5307.1991] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We reexamined the influence of fimE, also referred to as hyp, on type 1 fimbriation in Escherichia coli K-12. We found that one strain used previously and extensively in the analysis of type 1 fimbriation, strain CSH50, is in fact a fimE mutant; the fimE gene of CSH50 contains a copy of the insertion sequence IS1. Using a recently described allelic exchange procedure, we transferred the fimE::IS1 allele from CSH50 to our present wild-type strain, MG1655. Characterization of this IS1-containing strain (AAEC137), together with another fimE mutant of MG1655 (AAEC143), led to two conclusions about the role of fimE. First, the formation of phase variant colony types, reported widely in strains of E. coli, depends on mutation of fimE, at least in K-12 strain MG1655. Here we showed that this phenomenon reflects the ability of fimE to stimulate the rapid inversion of the fim invertible element from on to off when the bacteria are grown on agar. Second, our analysis of fimE mutants, which is limited to chromosomal constructs, provided no evidence that they are hyperfimbriate. We believe that these results, which are at odds with a previous study using fim-containing multicopy plasmids, reflect differences in gene copy number.
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Affiliation(s)
- I C Blomfield
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109-0620
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6
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Donaldson SG, Azizi SQ, Dal Nogare AR. Characteristics of aerobic gram-negative bacteria colonizing critically ill patients. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1991; 144:202-7. [PMID: 1676571 DOI: 10.1164/ajrccm/144.1.202] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Adherence of gram-negative bacteria (GNB) to epithelial surfaces is important for GNB colonization to occur. Pili, rodlike structures projecting from the outer membrane of GNB, and GNB surface hydrophobicity have been shown to enhance GNB adherence. We investigated the types of pili and the hydrophobicity of aerobic GNB colonizing the stomach, oropharynx, and trachea of critically ill patients. Piliation and hydrophobicity of oral, tracheal, and gastric GNB were compared with that of commensal GNB isolated from patients' rectums. Significantly more oropharyngeal than rectal GNB were piliated, and the most common type of pili present was type 1, or mannose-sensitive pili. Mannose-resistant and P pili were present less often, and no colonizing GNB had S pili. Colonizing GNB were hydrophilic rather than hydrophobic, and no differences in hydrophobicity were noted between colonizing GNB and rectal isolates. Our results suggest that pili may be important for oropharyngeal GNB colonization.
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Affiliation(s)
- S G Donaldson
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-9034
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Blomfield IC, Vaughn V, Rest RF, Eisenstein BI. Allelic exchange in Escherichia coli using the Bacillus subtilis sacB gene and a temperature-sensitive pSC101 replicon. Mol Microbiol 1991; 5:1447-57. [PMID: 1686293 DOI: 10.1111/j.1365-2958.1991.tb00791.x] [Citation(s) in RCA: 303] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To facilitate efficient allelic exchange of genetic information into a wild-type strain background, we improved upon and merged approaches using a temperature-sensitive plasmid and a counter-selectable marker in the chromosome. We first constructed intermediate strains of Escherichia coli K12 in which we replaced wild-type chromosomal sequences, at either the fimB-A or lacZ-A loci, with a newly constituted DNA cassette. The cassette consists of the sacB gene from Bacillus subtilis and the neomycin (kanamycin) resistance gene of Tn5, but, unlike another similar cassette, it lacks IS1 sequences. We found that sucrose sensitivity was highly dependent on incubation temperature and sodium chloride concentration. The DNA to be exchanged into the chromosome was first cloned into derivatives of plasmid pMAK705, a temperature-sensitive pSC101 replicon. The exchanges were carried out in two steps, first selecting for plasmid integration by standard techniques. In the second step, we grew the plasmid integrates under non-selective conditions at 42 degrees C, and then in the presence of sucrose at 30 degrees C, allowing positive selection for both plasmid excision and curing. Despite marked locus-specific strain differences in sucrose sensitivity and in the growth retardation due to the integrated plasmids, the protocol permitted highly efficient exchange of cloned DNA into either the fim or lac chromosomal loci. This procedure should allow the exchange of any DNA segment, in addition to the original or mutant allelic DNA, into any non-essential parts of the E. coli chromosome.
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Affiliation(s)
- I C Blomfield
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109
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Blomfield IC, McClain MS, Eisenstein BI. Type 1 fimbriae mutants of Escherichia coli K12: characterization of recognized afimbriate strains and construction of new fim deletion mutants. Mol Microbiol 1991; 5:1439-45. [PMID: 1686292 DOI: 10.1111/j.1365-2958.1991.tb00790.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have used Southern hybridization analysis to characterize the extent of fim homology in recognized type 1 fimbriae mutants of Escherichia coli K12, including strains HB101, P678-54, and VL584. We have found extensive homology in strain HB101, and confirm that P678-54 lacks the majority of fim DNA. Strain VL584 contains a deletion of the entire fim region. We have used a new allelic exchange procedure to generate novel fim deletion derivatives of strains MG1655, MM294, and YMC9. To increase the utility of the new deletion strains we also isolated recA derivatives of each mutant. These strains facilitate the isolation, characterization, and manipulation of cloned fimbriae genes from diverse sources.
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Affiliation(s)
- I C Blomfield
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109
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9
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Future Approaches to the Management of Urinary Tract Infections. Emerg Med Clin North Am 1991. [DOI: 10.1016/s0733-8627(20)30494-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Biggemann B, Bunse T, Sachsenweger A, Opferkuch W. Isolation and characterization of monoclonal antibodies directed against different epitopes of type-1-like fimbriae from a multifimbriated E. coli strain. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1990; 274:155-73. [PMID: 1707625 DOI: 10.1016/s0934-8840(11)80099-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Monoclonal antibodies (MAbs) were raised against purified fimbriae isolated from the uropathogenic E. coli strain WF96 (O7:K1:H6:F11rel,F10). This strain expresses at least four different types of fimbriae. 11 MAbs were selected for further characterization. They are directed against epitopes of a fimbrial type which is composed of 19.5 kDa subunits. It resembles type 1 fimbriae with regard to its high resistance to disruption by SDS. The MAbs were tested for crossreactivity to type 1 fimbriae and other fimbriae with known F-serotypes by ELISA. Two of these MAbs, Pili III 2F7 and Pili III 68C5, were directed against an epitope which was also found on MS fimbriae (type 1). Thus type 1 like fimbriae of E. coli WF96 share at least one epitope with MS fimbriae. Nevertheless, the antigenic properties of these two fimbrial types were found not to be completely identical, since all the other 9 MAbs were not crossreactive. The MAbs were not able to inhibit haemagglutination of erythrocytes of different species and thus not directed against adhesive sites of the fimbriae. All the epitopes detected by MAbs were accessible on native fimbriae; some of them were also detectable on denatured fimbrial subunits. Electron micrographs revealed that these epitopes were evenly distributed on the fimbrial organelle.
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Affiliation(s)
- B Biggemann
- Lehrstuhl für Medizinische Mikrobiologie und Immunologie der Ruhr-Universität Bochum
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11
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Weyant RS, Bibb WF, Stephens DS, Holloway BP, Moo-Penn WF, Birkness KA, Helsel LO, Mayer LW. Purification and characterization of a pilin specific for Brazilian purpuric fever-associated Haemophilus influenzae biogroup aegyptius (H. aegyptius) strains. J Clin Microbiol 1990; 28:756-63. [PMID: 1970577 PMCID: PMC267789 DOI: 10.1128/jcm.28.4.756-763.1990] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Brazilian purpuric fever (BPF) is a recently described fatal pediatric disease caused by systemic infection with Haemophilus influenzae biogroup aegyptius. Previous studies have shown that all H. influenzae biogroup aegyptius strains isolated from BPF cases and case contacts share several unique phenotypic and genotypic characteristics that differentiate them from other H. influenzae biogroup aegyptius strains isolated from conjunctivitis cases in Brazil. One key characteristic of this BPF clone is reactivity in a BPF-specific monoclonal antibody enzyme-linked immunosorbent assay. We have purified and partially characterized a pilin, referred to as the 25-kilodalton (kDa) protein. Aggregates of this protein contain a heat-labile epitope which is recognized by a monoclonal antibody used in the BPF-specific enzyme-linked immunosorbent assay. The protein has a molecular weight of approximately 25,000, is insoluble in most detergents, and fractionates with outer membrane vesicles after LiCl extraction. Biochemical analysis of the 25-kDa protein shows it to have an amino acid composition similar but not identical to that of the H. influenzae type b pilin. The sequence of 20 N-terminal amino acids of the 25-kDa protein shows almost complete homology with the N terminus of the H. influenzae type b pilin and the types 1 and P pilins of Escherichia coli. Transmission electron microscopic analysis of the purified protein shows the presence of filamentous structures similar in morphology to those of H. influenzae pili. Reactivity between the 25-kDa protein and the BPF-specific monoclonal antibody is demonstrated by Western blotting (immunoblotting) and colloidal gold-enhanced immunoelectron microscopy. Hemadsorption analysis shows that expression of this protein is associated with increases in piliated cells and enhanced binding of these cells to human erythrocytes. These studies indicate that expression of the 25-kDa protein is a characteristic unique to the BPF clone and suggest that this protein plays a role in the pathogenesis of BPF.
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Affiliation(s)
- R S Weyant
- Department of Pathology and Veterans Administration Medical Center
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12
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Schwan WR, Waltenbaugh C, Duncan JL. Bacteria as solid phase in a concentration fluorescence immunoassay analysis of antibodies to surface antigens. J Immunol Methods 1990; 126:247-52. [PMID: 1968082 DOI: 10.1016/0022-1759(90)90157-q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A modified solid-phase fluorescence immunoassay was developed using bacterial cells as the solid phase to screen antibodies produced against surface antigens from a clinical isolate of Escherichia coli, strain 1-149. The bacterial solid phase was used to analyze both polyclonal and monoclonal antibodies. The bacterial concentration fluorescence immunoassay (BCFIA) showed up to 50-fold greater sensitivity in bacterial cell detection as compared to ELISA (enzyme-linked immunosorbent assay). Moreover, BCFIA was considerably faster than ELISA with uniform reproducibility. This paper demonstrates the utility of using bacteria and their surface antigens as solid-phase matrices for antibody characterization in a FIA.
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Affiliation(s)
- W R Schwan
- Department of Microbiology-Immunology, Northwestern University, Chicago, IL 60611
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13
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Wust CJ, Nicholas JA, Fredin D, Dodd DC, Brideau RJ, Levely ME, Brown A. Monoclonal antibodies that cross-react with the E1 glycoprotein of different alphavirus serogroups: characterization including passive protection in vivo. Virus Res 1989; 13:101-12. [PMID: 2773592 DOI: 10.1016/0168-1702(89)90009-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A panel of four monoclonal antibodies (mAb) were produced that cross-react with representatives of two different togavirus serogroups, namely sindbis (SIN) and Semliki Forest (SF) viruses, by ELISA and ADCMC assays. Three of these mAb, IgG2a and IgG2b isotypes, passively protected C3H/Hej mice against 10 and 100 LD50 of SF challenge and one, IgM, did not protect against either challenge dose, or even at 1 LD50. All these mAb were cross-reactive with the E1 glycoprotein of the viruses by immunoblotting in which three different patterns of reactivity were evident, suggesting that three epitopes were involved. The patterns depended upon whether the mAb recognized E1 extracted from purified virions or infected cells and whether SDS-PAGE and immunoblotting were done in the presence or absence of beta-mercaptoethanol. One mAb (IgM) reacted with nonreduced or reduced E1 from either virions or cells suggesting recognition of a linear epitope. The other three mAb reacted with nonreduced but not reduced E1 from virions suggesting that recognition depends upon conformational epitopes. These three mAb reacted also with nonreduced E1 extracted from SF-infected cells whereas only one reacted with nonreduced E1 extracted from SIN-infected cells.
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Affiliation(s)
- C J Wust
- Department of Microbiology, College of Liberal Arts, University of Tennessee, Knoxville 37996
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Kudo Y, Yanagawa R, Hiramune T. Isolation and characterization of monoclonal antibodies against pili of Corynebacterium renale and Corynebacterium pilosum. Vet Microbiol 1987; 13:75-85. [PMID: 2433832 DOI: 10.1016/0378-1135(87)90101-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Five monoclonal antibodies against pili of Corynebacterium renale 115 P+ (piliated clone) and two monoclonal antibodies against pili of C. pilosum 92 P+ (piliated clone) were produced. These antibodies bound to pili of the homologous strain in in enzyme-linked immunosorbent assay (ELISA) and agglutinated P+ but not P- (non-piliated clone) of each homologous strain. The five monoclonal antibodies against C. renale 115 P+ pili were divided into 2 groups, comprising 16/5, 160/1 and 32/6 and 13/4 and B20/3, based on the results of a competitive binding assay. The results may indicate the presence of at least 2 distinct antigenic areas on the pilus of C. renale 115 P+. The monoclonal antibodies of the first group inhibited adhesion of C. renale 115 P+ bacteria to the epithelial cells of bovine vulva, while the second group did not. Two monoclonal antibodies against C. pilosum 92 P+ pili recognized the same area on the pilus of C. pilosum 92 P+, and inhibited the adhesion of C. pilosum 92 P+ bacteria to the epithelial cells of bovine vulva. The adhesion of these bacteria was inhibited by the monoclonal antibodies in the form of IgG as well as by the Fab fragment. The strains of C. renale and C. pilosum which reacted with each of the anti-C. renale 115 P+ pili and anti-C. pilosum 92 P+ pili monoclonal antibodies were small in number and of restricted distribution.
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Lowe MA, Holt SC, Eisenstein BI. Immunoelectron microscopic analysis of elongation of type 1 fimbriae in Escherichia coli. J Bacteriol 1987; 169:157-63. [PMID: 2878917 PMCID: PMC211747 DOI: 10.1128/jb.169.1.157-163.1987] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Using 10- and 20-nm-diameter gold particles conjugated to an antifimbrial monoclonal antibody, we analyzed the location of assembly of newly formed subunits on growing type 1 fimbriae of Escherichia coli. Fimbriae were removed from an E. coli K-12-derived strain, CSH50, by blending. Blended cells were allowed to regenerate their fimbriae in growth medium for approximately 25 min, after which they were labeled with a 20-nm-gold-monoclonal antibody probe. Continued outgrowth of these labeled fimbriae was allowed for additional time intervals, after which they were labeled with a 10-nm-gold-monoclonal antibody probe. The resulting fimbriae, double labeled with 10- and 20-nm-diameter gold particles, were examined in an electron microscope. The pattern of labeling on individual fimbrial organelles indicated morphologically that newly synthesized subunits are added to a growing organelle at its base.
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Elder BL, Fives-Taylor P. Characterization of monoclonal antibodies specific for adhesion: isolation of an adhesin of Streptococcus sanguis FW213. Infect Immun 1986; 54:421-7. [PMID: 3770949 PMCID: PMC260178 DOI: 10.1128/iai.54.2.421-427.1986] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Monoclonal antibodies reactive to an adhesive strain of Streptococcus sanguis (FW213) and nonreactive to a nonadhesive mutant (JL7) were derived from the fusion of myeloma line X63Ag8.653 and spleen cells from BALB/c mice immunized with live S. sanguis cells. Five cell lines, belonging to subclasses of immunoglobulin G, produced monoclonal antibodies specifically directed against the adhesive strain. All five antibodies also failed to react with five additional, independently isolated, nonadhesive mutants. A spontaneous mutant of FW213 (VT508) that no longer reacted with monoclonal antibody F51 (MAbF51) was isolated by serial agglutination with the antibody. Langmuir adsorption isotherms of VT508 indicated that this mutant also had altered ability to adhere to saliva-coated hydroxyapatite further confirming the specificity of MAbF51 for adhesion. Electron microscopy revealed that VT508 had lost the peritrichous fimbriae associated with the adhesion of FW213. MAbF51 was used to purify the adhesin from lysozyme cell extracts by using an affinity column of MAbF51 linked to Sephacryl S1000. Purity was suggested by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and crossed immunoelectrophoresis (CIEP). The adhesin had a molecular weight greater than 150,000 and was not denatured in sodium dodecyl sulfate reducing gels. Two peaks of near electrophoretic mobility were detected in CIEP when the purified material was run against polyclonal antibody to the whole cell. Tandem CIEP analysis and immunoprecipitation provided evidence that the two peaks represented the same antigen in two different forms.
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Alkan ML, Wong L, Silverblatt FJ. Change in degree of type 1 piliation of Escherichia coli during experimental peritonitis in the mouse. Infect Immun 1986; 54:549-54. [PMID: 2876964 PMCID: PMC260196 DOI: 10.1128/iai.54.2.549-554.1986] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
To determine whether expression of type 1 pili varies during the course of Escherichia coli infection in vivo, mice were injected intraperitoneally with 5 X 10(7) CFU of piliated or nonpiliated phase variants per ml, and the degree of piliation was measured in peritoneal exudate by an enzyme-linked immunosorbent assay inhibition method. In the animals challenged with the piliated bacteria, the numbers of organisms increased a log over 9 h and the amount of pilus antigen decreased from 3 to 0.075 micrograms/10 bacteria. After a 4-h delay, nonpiliated bacteria also increased by one log over 9 h; however, the amount of piliation remained virtually undetectable. Piliated E. coli were more virulent than nonpiliated variants in this model (50% lethal dose of 7.5 X 10(6) versus 3 X 10(7), respectively). The difference was significantly reduced by prior passive immunization with rabbit serum containing high titers of antipili antibody. Piliated bacteria adhered in significantly greater numbers to isolated mouse peritoneal membranes than did nonpiliated variants (15,400 +/- 2,700 versus 1,300 +/- 700 bacteria/mm2, respectively; P = 0.05). Adherence was inhibited by the presence of 0.1 M alpha methyl mannose (1,500 +/- 1,800 bacteria/mm2, P = 0.01). These results confirm the results of previous qualitative studies showing that phase variation of type 1 pili occurs in vivo and suggest that these pili may confer an initial advantage for growth of E. coli in the peritoneal cavity, presumably by fostering colonization of the peritoneal serosal surface.
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Angulo AF, Jansen WH, Osterhaus AD, Uytdehaag FG, Maas HM, Guinée PA. Monoclonal antibodies against the K99 antigen of Escherichia coli for diagnostic purposes. ZENTRALBLATT FUR BAKTERIOLOGIE, MIKROBIOLOGIE, UND HYGIENE. SERIES A, MEDICAL MICROBIOLOGY, INFECTIOUS DISEASES, VIROLOGY, PARASITOLOGY 1986; 261:204-11. [PMID: 3090803 DOI: 10.1016/s0176-6724(86)80037-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hybridomas secreting monoclonal antibodies against the K99 antigen of Escherichia coli were produced by the fusion of spleen cells from immunized BALB/c mice with P3/X63-Ag8.653 myeloma cells. The seven hybridomas which produced the highest antibody titers in vitro, as detected by enzyme-linked immunosorbent assay (ELISA) and Perma slide agglutination test (PSAT), were chosen for antibody production in vivo. No cross reaction was observed with K88ab, F41 and P987 antigens in the ELISA. The titer of each ascitic fluid was established by the ELISA and the slide agglutination (SAT) tests. The two ascitic fluids with the highest titer in the SAT were incorporated into the set of antisera used for serotyping at our laboratory. The results were satisfactory both in terms of stability and specificity.
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Gander RM, Thomas VL. Utilization of anion-exchange chromatography and monoclonal antibodies to characterize multiple pilus types on a uropathogenic Escherichia coli O6 isolate. Infect Immun 1986; 51:385-93. [PMID: 2867972 PMCID: PMC262335 DOI: 10.1128/iai.51.2.385-393.1986] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Multiple pilus types from a uropathogenic strain of Escherichia coli O6, strain 6260, were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), high-pressure liquid chromatography, binding assays, and erythrocyte adsorption. In addition, monoclonal antibodies were raised against purified pili of E. coli 6260 and used for immunological characterization. SDS-PAGE analysis of the purified pili showed at least three different subunits with molecular weights of 15,700, 17,800, and 19,300. SDS-PAGE analysis of four protein peaks from anion-exchange chromatography of intact pili showed polypeptides with molecular weights of 19,300 (fraction 1), 15,700 (fraction 2), and 17,800 and 15,700 (both fractions 3 and 4). Erythrocyte adsorption of the whole-pilus preparation removed the 17,800-molecular-weight subunit (17.8K subunit) and reduced the 15.7K subunit. Pili from an isogenic hemagglutination-negative variant of E. coli 6260, showing only the 15.7K and 19.3K subunits by SDS-PAGE, lacked the 17.8K subunit of fractions 3 and 4 present in the parent high-pressure liquid chromatography profile. Our data suggest that two of the pilus subunits, the 15.7K and 17.8K subunits, mediate mannose-resistant agglutination of human erythrocytes. Pili in fractions 1 and 2 from the parent strain bound specifically to mannose residues, while pili in fraction 4 bound to P-coated horse erythrocytes; no receptor specificity was identified for pili in fraction 3. Immunological analysis by the immunoblot technique showed that monoclonal antibody 11-2 reacted with the 19.3K subunit, monoclonal antibodies 34-3 and 73-3 reacted with the 15.7K subunit, and monoclonal antibodies 81-1, 82-1, and 91-1 reacted with polymers of subunits retained in the stacking gel. Intact pili precipitated by any of the six monoclonal antibodies showed two polypeptides by SDS-PAGE: 15.7K and 19.3K polypeptides for monoclonal antibody 11-2, and 15.7K and 17.8K polypeptides for monoclonal antibodies 34-3, 73-3, 81-1, 82-1, and 91-1. The cross-reactivity of the monoclonal antibodies with purified pili from other E. coli strains was determined by enzyme-linked immunosorbent assay. Monoclonal antibody 11-2 showed no significant cross-reactivity with heterogeneous pili. In contrast, the other monoclonal antibodies showed equivalent or greater reactivity with P pili from heterologous strains as compared with reactivity with E. coli 6260 pili.(ABSTRACT TRUNCATED AT 400 WORDS)
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Abraham JM, Freitag CS, Clements JR, Eisenstein BI. An invertible element of DNA controls phase variation of type 1 fimbriae of Escherichia coli. Proc Natl Acad Sci U S A 1985; 82:5724-7. [PMID: 2863818 PMCID: PMC390624 DOI: 10.1073/pnas.82.17.5724] [Citation(s) in RCA: 322] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The expression of type 1 fimbriae (pili) of Escherichia coli is turned on and off at the transcriptional level at a high frequency (10(-3) per cell per generation) in a process termed phase variation. Using Southern blot and DNA sequence analysis, we have detected a genomic rearrangement in the switch region immediately upstream of the fimbrial structural gene. This rearrangement involves an invertible 314-base-pair segment of DNA whose alternating orientation apparently results in the on-and-off activation of a promoter that determines the state of fimbrial expression.
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Freitag CS, Abraham JM, Clements JR, Eisenstein BI. Genetic analysis of the phase variation control of expression of type 1 fimbriae in Escherichia coli. J Bacteriol 1985; 162:668-75. [PMID: 2859269 PMCID: PMC218902 DOI: 10.1128/jb.162.2.668-675.1985] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Expression of type 1 fimbriae in Escherichia coli exhibits phase variation, whereby individual cells can alternate between states of organelle expression (Fim+) and nonexpression (Fim-). Strains with a fimD-lac operon fusion, in which lac, rather than fimD, expression is under the control of the fimD promoter, undergo Lac+ in equilibrium Lac- phase variation, instead. After positioning a lambda prophage adjacent to the operon fusion, we were able to isolate specialized lambda phage carrying both the fimD-lac fusion and the phase variation control region. Introduction of such phage into an Fim+ strain resulted in construction of a strain with a double, independently switching phenotype (Fim+ in equilibrium Fim- and Lac+ in equilibrium Lac-), demonstrating that the region controlling phase variation is contiguous with the fimD-lac operon fusion and is cis acting. When the specialized lambda phage was propagated on a delta lac delta fim strain, phase variation occurred within the plaques, confirming that the phase variation control region is carried on the specialized transducing phage. All lysogens acquired the Lac+ in equilibrium Lac- phenotype, except for two nonswitching Lac+ recombinants, which acquired Lac+ in equilibrium Lac- phase variation only by trans complementation with fim. Phase variation of type 1 fimbriae, therefore, appears to involve both a cis-active element, which is cloned on a specialized lambda phage, and a trans-active permissive factor, which is not present on the phage, but rather must be supplied by the recipient strain in the transduction.
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Dodd DC, Eisenstein BI. Kinetic analysis of the synthesis and assembly of type 1 fimbriae of Escherichia coli. J Bacteriol 1984; 160:227-32. [PMID: 6148332 PMCID: PMC214705 DOI: 10.1128/jb.160.1.227-232.1984] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The adhesive organelles (type 1 fimbriae) of K-12 and other isolates of Escherichia coli are composed of identical 17,000-dalton subunits. We examined the assembly of these subunits into fimbrial organelles. After synthesis, the nascent subunits were first processed and then assembled into the organelles; the assembly step took almost 3 min in log-phase cultures at 37 degrees C. Even during blockage of protein synthesis, the free subunits continued to assemble until the pool was depleted. This pool was small in comparison with the amount of total fimbrial protein already assembled into surface organelles and was not sufficient to regenerate new detectable organelles after the removal of preexistent ones by blending. Assembly appeared to slow when the metabolic rate of the bacterial cells slowed, since subunits took longer to appear in the organelles at lower than optimal temperatures or as a culture entered the stationary phase. The synthetic rate of subunits slowed sooner than that of total cellular proteins as a culture approached the stationary phase and ceased completely as the culture entered the stationary phase. The amount of fimbrial antigen expressed on the surface of the cells remained relatively constant during growth of a culture.
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Dodd DC, Bassford PJ, Eisenstein BI. Dependence of secretion and assembly of type 1 fimbrial subunits of Escherichia coli on normal protein export. J Bacteriol 1984; 159:1077-9. [PMID: 6148331 PMCID: PMC215775 DOI: 10.1128/jb.159.3.1077-1079.1984] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The export of fimbrial subunits was found to be diminished at the restrictive temperature in a strain bearing a secA(Ts) mutation. Likewise, export was inhibited in a strain harboring a malE-lacZ protein fusion upon induction of hybrid protein synthesis. Both conditions resulted in the accumulation of a precursor protein ca. 2,000 daltons larger than the mature fimbrial subunit.
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