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comparative in vitro and in vivo susceptibilities of the lyme disease spirochete borrelia burgdorferi to cefuroxime and other antimicrobial agents.the in vitro and in vivo susceptibilities of the lyme disease pathogen borrelia burgdorferi to cefuroxime were compared with those of several other antibiotics commonly used to treat this disease. cefuroxime demonstrated a higher mbc in vitro (1.0 microgram/ml) than ceftriaxone (0.08 microgram/ml) or erythromycin (0.32 microgram/ml), but the mbc was similar to that of amoxicillin (0.8 microgram/ml) and doxycycline (1.6 micrograms/ml). b. burgdorferi was considerably less susceptible to tetracycl ...19902073103
interference between borreliae and trypanosomes. i. antigenic analysis, fluorescent antibody and immobilisine studies of borrelia turicatae and trypanosoma cruzi. 19734202640
immunoglobulins and antibodies in borrelia turicatae infections. 19694390863
helical conformation of treponema pallidum (nichols strain), treponema paraluis-cuniculi, treponema denticola, borrelia turicatae, and unidentified oral spirochetes.borrelia turicatae (mouse virulent) and treponema denticola, a small oral treponeme, formed right-handed helices as determined by scanning electron microscopy. treponema pallidum (nichols strain), treponema paraluis-cuniculi, and two unidentified oral spirochetes displayed left-handed helices.19817019083
in vivo evidence that an intact lytic complement pathway is not essential for successful removal of circulating borrelia turicatae from mouse blood.complement component c5-deficient mice were found to be able to eliminate blood-borne borrelia turicatae as effectively as normocomplementemic control animals. the absence of c5 and the resultant loss of hemolytic complement activity were confirmed for the deficient mouse strains used. immunofluorescent staining of complement component c3 on blood-derived borreliae could be readily accomplished as early as 2 days before spirochetal elimination from all mice tested. these observations would sugge ...19817216454
genetic and phenotypic analysis of borrelia miyamotoi sp. nov., isolated from the ixodid tick ixodes persulcatus, the vector for lyme disease in japan.the ixodid tick ixodes persulcatus is the most important vector of lyme disease in japan. most spirochete isolates obtained from i. persulcatus ticks have been classified as borrelia burgdorferi sensu lato because of their genetic, biological, and immunological characteristics. however, we found that a small number of isolates obtained from i. persulcatus contained a smaller 38-kda endoflagellar protein and single 23s-5s rrna gene unit. representative isolate ht31t (t = type strain) had the same ...19957547303
comparison of borrelia isolated from uk foci of lyme disease.restriction endonuclease digestion of linear borrelial chromosomal dna showed that three isolates of uk lyme disease spirochaetes differed markedly from each other and from published data for other isolates from north america and continental europe. analysis of linear plasmid bands revealed that uk isolates differed from each other in the number and sizes of the plasmids in isolates from different foci of uk lyme disease. fatty acid analysis (of fatty acid methyl ester (fame) profiles) showed th ...19957649436
phenotypic analysis of outer surface protein c (ospc) of borrelia burgdorferi sensu lato by monoclonal antibodies: relationship to genospecies and ospa serotype.molecular analyses of the genes encoding ospc, a major immunodominant protein of borrelia burgdorferi sensu lato, revealed a considerable degree of heterogeneity. in the present study, we investigated whether a similar heterogeneity of the ospc phenotype can be shown by analysis with monoclonal antibodies (mabs). thirteen ospc-specific mabs (l22 mabs) were produced by immunizing mice with either different combinations of whole-cell antigens or recombinantly expressed ospcs cloned from strains be ...19957699024
differential association of borrelia species with cultured neural cells.studies of the interactions of relapsing fever borrelia species with cultured neural cells have not been reported. in the present work, the interaction of the relapsing fever agents borrelia hermsii and borrelia turicatae with cultured neural and endothelial cells was studied and compared with borrelia burgdorferi, the agent of lyme disease. all borrelia species bound each cell type tested. host cell association was time-dependent and saturable. with the exception of human neuron cells, b. herms ...19948106781
prevalence of antibodies to borrelia burgdorferi, borrelia parkeri and borrelia turicatae in human settlements of the cordillera province, bolivia.a seroepidemiological study to determine the prevalence of human lyme borreliosis and tick-borne relapsing fever was carried out in three communities (camiri, boyuibe and gutierrez) of the cordillera province, santa cruz department, south-eastern bolivia. anti-b. burgdorferi, anti-b. turicatae and anti-b. parkeri antibodies, tested by the indirect immunofluorescent assay (ifa), were detected in 10.8, 16.1 and 8.2% of the serum samples tested, and confirmed by ifa-abs in 1.3, 1.3 and 1.0%, respec ...19948107167
variability of a bacterial surface protein and disease expression in a possible mouse model of systemic lyme borreliosis.during persistent infection of scid mice with borrelia turicatae, an agent of relapsing fever and neuroborreliosis, there was variation in the surface proteins the bacteria expressed and in disease manifestations over time. two serotypes, a and b, were isolated from the mice, cloned by limiting dilution, and further characterized. the only discernible difference between the two variants was in the size of the major surface protein they expressed: serotype a had a variable major protein (vmp) of ...19948294872
an ospa antigen-capture enzyme-linked immunosorbent assay for detecting north american isolates of borrelia burgdorferi in larval and nymphal ixodes dammini.an antigen-capture enzyme-linked immunosorbent assay (elisa) was developed for detecting north american isolates of borrelia burgdorferi in larval, nymphal, and adult ticks. the assay uses an anti-ospa monoclonal antibody (h5332) for antigen capture and biotin-labelled polyclonal sera with streptavidinhorseradish peroxidase for signal generation. the assay recognized 15 of 15 north american b. burgdorferi isolates and did not cross-react with spirochete antigens of borrelia hermsii, borrelia tur ...19938432812
uptake and killing of lyme disease and relapsing fever borreliae in the perfused rat liver and by isolated kupffer cells.in situ-perfused rat livers were infused with a single dose of 1.5 x 10(7) radiolabeled borreliae. significant (p < 0.00005) differences in the liver uptake of the agents of lyme borreliosis, borrelia burgdorferi irs, borrelia afzelii vs461, and borrelia garinii pbi, and that of the agents of relapsing fever, borrelia hermsii, borrelia parkeri, and borrelia turicatae, were observed. the liver uptakes ranged between 65.9% for b. burgdorferi irs and 40.5% for b. turicatae. neither relapsing fever ...19968613404
binding of human urokinase type plasminogen activator and plasminogen to borrelia species.borrelia burgdorferi binds human urokinase plasminogen activator (upa), which cleaves plasminogen (pgn) to plasmin. the ability of other borrelia species to bind upa, pgn, or both was investigated. borrelia coriacae, borrelia garinii, borrelia parkeri, borrelia anserina, and borrelia turicatae were compared with infectious and noninfectious b. burgdorferi isolates. all borrelia species lacked endogenous proteases capable of digesting casein, but all species bound human upa and pgn, generating pg ...19968656020
in vitro susceptibility of thirty borrelia strains from various sources against eight antimicrobial chemotherapeutics.minimal inhibitory concentrations (mic) and minimal bactericidal concentrations (mbc) were evaluated of the antimicrobial chemotherapeutics amoxicillin, azithromycin, cefotaxime, ceftriaxone, doxycycline, penicillin g sodium, roxithromycin, and trimethoprim-sulfamethoxazole for 30 borrelia strains from various sources (skin, cerebrospinal fluid, ticks). of these strains 29 were lyme disease agents of the species borrelia afzelii (n = 12), borrelia burgdorferi sensu stricto (n = 4), borrelia gari ...19968852472
phylogenesis of relapsing fever borrelia spp.the phylogenetic relationships of 20 relapsing fever (rf) borrelia spp. were estimated on the basis of the sequences of rrs genes. complete sequences were aligned and compared with previously published sequences, and the similarity values were found to be 97.7 to 99.9%. phylogenetic trees were constructed by using the three neighbor-joining, maximum-parsimony, and maximum-likelihood methods. the results of the comparative phylogenetic analysis divided the rf borrelia spp. into three major cluste ...19968863409
phylogenetic analysis of borrelia species based on flagellin gene sequences and its application for molecular typing of lyme disease borreliae.we determined almost complete flagellin gene sequences of various borrelia species and aligned them with previously published sequences. a neighbor-joining phylogenetic analysis showed that the genus borrelia was divided into the following three major clusters: new world relapsing fever borreliae (borrelia turicatae, borrelia parkeri, and borrelia hermsii), old world relapsing fever borreliae (borrelia crocidurae, borrelia duttonii, and borrelia hispanica), and lyme disease borreliae (borrelia b ...19968863416
physical mapping of the borrelia miyamotoi ht31 chromosome in comparison with that of borrelia turicatae, an etiological agent of tick-borne relapsing fever.we report the construction of physical maps of chromosomes for borrelia miyamotoi ht31 (a new species of borrelia) and borrelia turicatae (relapsing fever agent) by pulsed-field gel electrophoresis of dna fragments generated by digestion of chromosomal dna with rare-cutting restriction endonucleases and reciprocal hybridization. the size of the b. miyamotoi ht31 chromosome was calculated to be approximately 925 kilobase pairs, and the chromosome for b. turicatae was estimated to be 951 kilobase ...19968877131
arthritis severity and spirochete burden are determined by serotype in the borrelia turicatae-mouse model of lyme disease.immunodeficient mice infected with borrelia turicatae, a relapsing fever agent, have a disorder that resembles disseminated lyme disease. two serotypes, a and b, differed in their arthritogenicity in both cb-17 scid and c3h scid mice. in cb-17 scid mice infected with serotype a or b, arthritis was assessed by measurement of tibiotarsal diameter, functional ability on a beam walk test, and microscopic assessment of joint inflammation. serotype b-infected mice had greater joint swelling, functiona ...19978975925
a phylogenetic analysis of borrelia burgdorferi sensu lato based on sequence information from the hbb gene, coding for a histone-like protein.we describe a phylogenetic investigation of borrelia burgdorferi sensu lato, the causative agent of lyme disease, based on a dna sequence analysis of the hbb gene, which encodes protein hbb, a member of the family of histone-like proteins. because of their intimate contact with the dna molecule, these proteins are believed to be fairly conserved through evolution. in this study we proved that the hbb gene is suitable for phylogenetic inference in the genus borrelia. the hbb gene, which is 327 bp ...19978995795
distinct characteristics of resistance to borrelia burgdorferi-induced arthritis in c57bl/6n mice.studies of mice infected with borrelia burgdorferi have indicated that the severity of arthritis is influenced by the genetic composition of the host: the c3h mouse develops severe arthritis while balb/c and c57bl/6 mice develop mild arthritis. in this study, the effects of increasing infectious dose on the severity of arthritis were determined in these three mouse strains. c3h/he mice developed severe arthritis at all infectious doses, with 100% infection requiring 200 spirochetes. in balb/cann ...19989423853
population structure of the relapsing fever spirochete borrelia hermsii as indicated by polymorphism of two multigene families that encode immunogenic outer surface lipoproteins.the tick-borne relapsing fever spirochete borrelia hermsii evades the mammalian immune system by periodically switching expression among members of two multigene families that encode immunogenic, antigenically distinct outer surface proteins. the type strain, b. hermsii hs1, has at least 40 complete genes and pseudogenes that participate in this multiphasic antigenic variation. originally termed vmp (for variable major protein) genes, they have been reclassified as vsp (for variable small protei ...19989453591
the spirochete borrelia crocidurae causes erythrocyte rosetting during relapsing fever.several species of the genus borrelia exhibit antigenic variation of variable major proteins on their surface during relapsing fever. we have investigated the african relapsing fever species borrelia crocidurae during infections in mice and compared it with the thoroughly studied north american species borrelia hermsii. a major difference between the two species is that b. crocidurae can bind and become completely covered with erythrocytes. in addition, b. crocidurae causes a prolonged spirochet ...19989453646
neuroborreliosis during relapsing fever: review of the clinical manifestations, pathology, and treatment of infections in humans and experimental animals.the spirochetal disease relapsing fever is caused by different borrelia species. relapsing fever is well recognized as an infection of the blood, but little is known about its predilection for the nervous system and the eyes. to investigate neurological and ocular involvement during relapsing fever, we reviewed the clinical manifestations, pathology, and treatment of relapsing fever of humans and experimental animals. the results indicate that borrelia turicatae and borrelia duttonii, the agents ...19989455525
isolation and characterization of the outer membrane of borrelia hermsii.the outer membrane of borrelia hermsii has been shown by freeze-fracture analysis to contain a low density of membrane-spanning outer membrane proteins which have not yet been isolated or identified. in this study, we report the purification of outer membrane vesicles (omv) from b. hermsii hs-1 and the subsequent identification of their constituent outer membrane proteins. the b. hermsii outer membranes were released by vigorous vortexing of whole organisms in low-ph, hypotonic citrate buffer an ...19989488399
a surface-exposed region of a novel outer membrane protein (p66) of borrelia spp. is variable in size and sequence.a model of the 66-kda outer membrane protein (p66) of lyme disease borrelia spp. predicts a surface-exposed loop near the c terminus. this region contains an antigen commonly recognized by sera from lyme disease patients. in the present study, this region of p66 and homologous proteins of other borrelia spp. were further investigated by using monoclonal antibodies, epitope mapping of p66 of borrelia burgdorferi, and dna sequencing. a monoclonal antibody specific for b. burgdorferi bound to the p ...19989537355
clearance of borrelia burgdorferi may not be required for resistance to experimental lyme arthritis.infection of inbred mouse strains with borrelia burgdorferi results in the development of experimental lyme arthritis. the degree of arthritic pathology has been suggested to correlate with the level of spirochete burden within tissues. to investigate this further, we infected resistant dba/2 (dba) and susceptible c3h/hej (c3h) mice in the hind footpads and monitored arthritis development for 21 days. to quantitate levels of spirochetes within tissues, we created a competitive pcr molecule conta ...19989573090
kinetics and in vivo induction of genetic variation of vlse in borrelia burgdorferi.the lyme disease agent, borrelia burgdorferi, is able to persistently infect humans and animals for months or years in the presence of an active immune response. it is not known how the organisms survive immune attack in the mammalian host. vlse, a gene localized near one end of linear plasmid lp28-1 and encoding a surface-exposed lipoprotein in b. burgdorferi b31, was shown recently to undergo extensive genetic and antigenic variation within 28 days of initial infection in c3h/hen mice. in this ...19989673250
cloning and molecular characterization of a multicopy, linear plasmid-carried, repeat motif-containing gene from borrelia turicatae, a causative agent of relapsing fever.borrelia turicatae is one of several spirochete species that can cause relapsing fever. here, we describe the identification and characterization of a gene from b. turicatae and other relapsing-fever spirochetes that exhibits homology with the rep+ and orf-e gene families of the lyme disease spirochetes. this gene, which we have designated repa, encodes a putative protein of 30.2 kda with an isoelectric point of 4.69. the central region of repa harbors a series of amino acid repeat motifs which ...19989733706
molecular analysis of sequence heterogeneity among genes encoding decorin binding proteins a and b of borrelia burgdorferi sensu lato.immunization of mice with borrelia burgdorferi decorin binding protein a (dbpa), one of two gene products of the dbpba locus, has been shown recently to confer protection against challenge. hyperimmune dbpa antiserum killed a large number of b. burgdorferi sensu lato isolates of diverse phylogeny and origin, suggesting conservation of the protective epitope(s). in order to evaluate the heterogeneity of dbpa and dbpb and to facilitate defining the conserved epitope(s) of these antigens, the seque ...19989784533
tick-borne relapsing fever in british columbia, canada: first isolation of borrelia hermsii.the spirochete that causes tick-borne relapsing fever, borrelia hermsii, was isolated in pure culture during 1995 and 1996 from three acutely ill human patients infected in southern british columbia, canada. the geographic area of exposure is a known focus of this disease dating back to 1930 when the first case was recognized in a human. analyses of plasmid dna, protein profiles, and reactivity with a species-specific monoclonal antibody identified the new isolates of spirochetes as b. hermsii, ...19989817862
treponema pallidum major sheath protein homologue tpr k is a target of opsonic antibody and the protective immune response.we have identified a family of genes that code for targets for opsonic antibody and protective immunity in t. pallidum subspecies pallidum using two different approaches, subtraction hybridization and differential immunologic screening of a t. pallidum genomic library. both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of treponema denticola. one of the members of this gene family, tpr k, codes for a pro ...19999989979
specific antibodies reactive with the 22-kilodalton major outer surface protein of borrelia anserina ni-nl protect chicks from infection.an outer surface lipoprotein of 22 kda was identified in the avian pathogen borrelia anserina ni-nl by using antibody preparations reactive with bacterial surface-exposed proteins. amino acid sequence analysis of the 22-kda protein demonstrated 90% identity with vmpa of b. turicatae, suggesting that the protein belongs to the family of 20-kda outer surface proteins of the genus borrelia. all of the 60 chicks intramuscularly treated with antibodies specifically reacting with the 22-kda protein an ...199910225933
access of antibody or trypsin to an integral outer membrane protein (p66) of borrelia burgdorferi is hindered by osp lipoproteins.the outer membrane of borrelia burgdorferi, the lyme disease agent, contains lipoproteins anchored by their lipid moieties and integral proteins with membrane-spanning regions. we used the techniques of in situ proteolysis, immunofluorescence, in vitro growth inhibition, and cross-linking with formaldehyde to characterize topological relationships between p66, an integral membrane protein, and selected osp lipoproteins of b. burgdorferi. protease treatment of intact spirochetes cleaved p66 and o ...199910338494
comparative analysis and immunological characterization of the borrelia bdr protein family.multiple circular and linear plasmids of lyme disease and relapsing fever borrelia spirochetes carry genes for members of the bdr (borrelia direct repeat) protein family. to define their common and divergent attributes, we first comprehensively compared the known homologs. bdr proteins with predicted sizes ranging from 10.7 to 30. 6 kda formed five homology groups, based on variable numbers of short direct repeats in a central domain and diverse n- and c-terminal domains. in a further characteri ...199910377099
characterization of vspb of borrelia turicatae, a major outer membrane protein expressed in blood and tissues of mice.serotypes a and b of the relapsing fever spirochete borrelia turicatae produce different disease manifestations in infected mice. whereas serotype b causes more severe arthritis and reaches higher densities in the blood of mice than serotype a, serotype a invades the central nervous system earlier than serotype b during infection. these differences between serotypes a and b in mice are associated with the expression of different surface proteins, vspa and vspb, respectively, in the culture mediu ...199910456910
dual role of interleukin-10 in murine lyme disease: regulation of arthritis severity and host defense.in the murine model of lyme disease, c3h/he mice exhibit severe arthritis while c57bl/6n mice exhibit mild lesions when infected with borrelia burgdorferi. joint tissues from these two strains of mice harbor similar concentrations of b. burgdorferi, suggesting that the difference in disease severity reflects differences in the magnitude of the inflammatory response to b. burgdorferi lipoproteins. stimulation of bone marrow macrophages from c3h/hen mice with the b. burgdorferi lipoprotein ospa re ...199910496888
characterization of a periplasmic atp-binding cassette iron import system of brachyspira (serpulina) hyodysenteriae.the nucleotide sequence of the pathogenic spirochete brachyspira hyodysenteriae bit (for "brachyspira iron transport") genomic region has been determined. the bit region is likely to encode an iron atp-binding cassette transport system with some homology to those encountered in gram-negative bacteria. six open reading frames oriented in the same direction and physically linked have been identified. this system possesses a protein containing atp-binding motifs (bitd), two hydrophobic cytoplasmic ...199910559160
molecular evidence for a new bacteriophage of borrelia burgdorferi.we have recovered a dnase-protected, chloroform-resistant molecule of dna from the cell-free supernatant of a borrelia burgdorferi culture. the dna is a 32-kb double-stranded linear molecule that is derived from the 32-kb circular plasmids (cp32s) of the b. burgdorferi genome. electron microscopy of samples from which the 32-kb dna molecule was purified revealed bacteriophage particles. the bacteriophage has a polyhedral head with a diameter of 55 nm and appears to have a simple 100-nm-long tail ...199910572135
molecular and evolutionary characterization of the cp32/18 family of supercoiled plasmids in borrelia burgdorferi 297.in this study, we characterized seven members of the cp32/18 family of supercoiled plasmids in borrelia burgdorferi 297. complete sequence analysis of a 21-kb plasmid (cp18-2) confirmed that the strain 297 plasmids are similar in overall content and organization to their b31 counterparts. of the 31 open reading frames (orfs) in cp18-2, only three showed sequence relatedness to proteins with known functions, and only one, a para/sopa ortholog, was related to nonborrelial polypeptides. besides the ...200010678977
stability of borrelia burgdorferi bdr loci in vitro and in vivo.the lyme disease spirochete borrelia burgdorferi expresses diverse subsurface yet antigenically cross-reactive bdr protein paralogs from distinct circular- and linear-plasmid loci. we assessed the possible effects of in vitro and in vivo growth on bdr locus structure, searching for recombinational events leading to either deletions or insertions of central repeat units or novel amino- and carboxy-terminus combinations. our data indicate that, apart from plasmid loss during in vitro cultivation, ...200010678998
molecular and immunological analyses of the borrelia turicatae bdr protein family.here, we describe the molecular and immunological characterization of the bdr gene family of borrelia turicatae, a relapsing-fever spirochete. nine bdr alleles belonging to two different subfamilies were sequenced and localized to linear plasmids. anti-bdr antiserum was generated and used to analyze bdr expression in pre- and postinfection isogenic populations. the analyses presented here provide a detailed characterization of the bdr proteins in a relapsing-fever spirochete species, enhancing o ...200010722647
the relapsing fever spirochete borrelia hermsii contains multiple, antigen-encoding circular plasmids that are homologous to the cp32 plasmids of lyme disease spirochetes.borrelia hermsii, an agent of tick-borne relapsing fever, was found to contain multiple circular plasmids approximately 30 kb in size. sequencing of a dna library constructed from circular plasmid fragments enabled assembly of a composite dna sequence that is homologous to the cp32 plasmid family of the lyme disease spirochete, b. burgdorferi. analysis of another relapsing fever bacterium, b. parkeri, indicated that it contains linear homologs of the b. hermsii and b. burgdorferi cp32 plasmids. ...200010858201
differentiation of borrelia burgdorferi sensu lato on the basis of rna polymerase gene (rpob) sequences.we determined the nucleotide sequences (329 bp) of the rpob dnas from 22 reference strains of borrelia. no insertions or deletions were observed. deduced amino acid sequences of amplified rpob dna comprised 109 amino acid residues (n(450) to m(558) [escherichia coli numbering]). all amino acid sequences were identical with the exception of those of borrelia lusitaniae potib2 (t(461)-->a) and b. bissettii dn127 (i(498)-->v). each species of b. burgdorferi sensu lato was differentiated as a distin ...200010878043
spirochaetal lipoproteins and pathogenesis. 200010878114
analysis of the cellular localization of bdr paralogs in borrelia burgdorferi, a causative agent of lyme disease: evidence for functional diversity.the bdr (borrelia direct repeat) gene family of the genus borrelia encodes a polymorphic group of proteins that carry a central repeat motif region containing putative phosphorylation sites and a hydrophobic carboxyl-terminal domain. it has been postulated that the bdr proteins may anchor to the inner membrane via the c-terminal domain. in this study, we used cellular fractionation methodologies, salt and detergent treatments, and immunoblot analyses to assess the association of the bdr proteins ...200010894730
serodiagnosis of louse-borne relapsing fever with glycerophosphodiester phosphodiesterase (glpq) from borrelia recurrentis.human louse-borne relapsing fever occurs in sporadic outbreaks in central and eastern africa that are characterized by significant morbidity and mortality. isolates of the causative agent, borrelia recurrentis, were obtained from the blood of four patients during a recent epidemic of the disease in southern sudan. the glpq gene, encoding glycerophosphodiester phosphodiesterase, from these isolates was sequenced and compared with the glpq sequences obtained from other relapsing-fever spirochetes. ...200011015364
structural conservation of neurotropism-associated vspa within the variable borrelia vsp-ospc lipoprotein family.vsp surface lipoproteins are serotype-defining antigens of relapsing fever spirochetes that undergo multiphasic antigenic variation to avoid the immune response. one of these proteins, vspa of borrelia turicatae, is also associated with neurotropism in infected mice. vsp proteins are highly polymorphic in sequence, which may relate to their specific antibody reactivities and host cell interactions. to determine whether sequence variations affect protein structure, we compared b. turicatae vspa w ...200111018048
surface protein variation by expression site switching in the relapsing fever agent borrelia hermsii.borrelia hermsii, an agent of relapsing fever, undergoes antigenic variation of serotype-specifying membrane proteins during mammalian infections. when b. hermsii is cultivated in broth medium, one serotype, 33, eventually predominates in the population. serotype 33 has also been found to be dominant in ticks but not in mammalian hosts. we investigated the biology and genetics of two independently derived clonal populations of serotype 33 of b. hermsii. both isolates infected immunodeficient mic ...200011083837
in vitro and in vivo neutralization of the relapsing fever agent borrelia hermsii with serotype-specific immunoglobulin m antibodies.the antigenic variation of the relapsing fever agent borrelia hermsii is associated with changes in the expression of the vlp and vsp outer membrane lipoproteins. to investigate whether these serotype-defining proteins are the target of a neutralizing and protective antibody response, monoclonal antibodies were produced from spleens of infected mice just after clearance of serotype 7 cells from the blood. two immunoglobulin m monoclonal antibodies, h7-7 and h7-12, were studied in detail. both an ...200111159997
isogenic serotypes of borrelia turicatae show different localization in the brain and skin of mice.mice with severe combined immunodeficiency (scid mice) and infected with the relapsing fever agent borrelia turicatae develop manifestations that resemble those of disseminated lyme disease. we have characterized two isogenic serotypes, a and b, which differ in their variable small proteins (vsps) and disease manifestations. serotype a but not serotype b was cultured from the brain during early infection, and serotype b caused more severe arthritis, myocarditis, and vestibular dysfunction than s ...200111292762
analysis of mechanisms associated with loss of infectivity of clonal populations of borrelia burgdorferi b31mi.numerous studies have provided suggestive evidence that the loss of plasmids correlates with the loss of infectivity of the lyme disease spirochetes. in this study we have further investigated this correlation. clonal populations were obtained from the skin of a mouse infected for 3 months with a clonal population of borrelia burgdorferi b31mi. the complete plasmid compositions of these populations were determined using a combination of pcr and southern hybridization. the infectivities of clones ...200111349029
impact of genotypic variation of borrelia burgdorferi sensu stricto on kinetics of dissemination and severity of disease in c3h/hej mice.various genotypes of borrelia burgdorferi sensu stricto have been previously identified among a large collection of isolates cultured from patients with lyme disease in the united states. furthermore, association of specific genotypes with hematogenous dissemination early in the disease course has been observed. the present study assessed kinetics of spirochete dissemination and disease severity in c3h/hej mice infected with two different genotypes of b. burgdorferi. spirochete load in plasma an ...200111401967
borrelia burgdorferi reva antigen is a surface-exposed outer membrane protein whose expression is regulated in response to environmental temperature and ph.borrelia burgdorferi, the causative agent of lyme disease, produces reva protein during the early stages of mammalian infection. b. burgdorferi apparently uses temperature as a cue to its location, producing proteins required for infection of warm-blooded animals at temperatures corresponding to host body temperature, but does not produce such virulence factors at cooler, ambient temperatures. we have observed that b. burgdorferi regulates expression of reva in response to temperature, with the ...200111500397
antigen polymorphism in borrelia hermsii, a clonal pathogenic bacterium.the relapsing fever spirochete, borrelia hermsii, escapes immune selection by alternating expression of surface lipoprotein alleles. the switch results from a duplicative transposition of one of several surface lipoprotein-encoding nucleotide sequences into the singular expression site. these nucleotide sequences constitute a large gene family whose diversity originated, in some cases, before the major divergences of borrelia species. we have examined the b. hermsii vsp subfamily of alleles, whi ...200111742066
equine abortion associated with the borrelia parkeri-b. turicatae tick-borne relapsing fever spirochete group.direct amplification and sequencing of the 16s rrna gene and a variable region of the flagellin gene from fetal liver-associated spirochetes belonging to the borrelia parkeri-b. turicatae tick-borne relapsing fever spirochete group with a late-term abortion in a mare are described.200211923397
evidence that the variable regions of the central domain of vlse are antigenic during infection with lyme disease spirochetes.it has been postulated that the vls system of the lyme disease spirochetes contributes to immune evasion through antigenic variation. while it is clear that vlse undergoes sequence change within its variable regions at a high frequency during the early stages of infection, a definitive role in immune evasion has not been demonstrated. in this report we assessed the murine and human humoral immune response to recombinant (r)-vlse variants that originally arose during infection in mice. immunoblot ...200212117928
disease severity in a murine model of lyme borreliosis is associated with the genotype of the infecting borrelia burgdorferi sensu stricto strain.the pathogenicity of borrelia burgdorferi sensu stricto clinical isolates representing 2 distinct ribosomal dna spacer restriction fragment-length polymorphism genotypes (rsts) was assessed in a murine model of lyme disease. b. burgdorferi was recovered from 71.5% and 26.6% of specimens from mice infected with rst1 and rst3 isolates, respectively (p<.0001). the average ankle diameter and histologic scores for carditis and arthritis were significantly higher after 2 weeks of infection among mice ...200212198612
characterization of p40, a cytadhesin of mycoplasma agalactiae.an immunodominant protein, p40, of mycoplasma agalactiae was analyzed genetically and functionally. the gene encoding p40 was cloned from type strain pg2, sequenced, submitted to point mutagenesis in order to convert mycoplasma-specific tga(trp) codon to the universal tgg(trp) codon, and subsequently expressed in escherichia coli. nucleotide sequence-derived amino acid sequence comparisons revealed a similarity of p40 to the adhesin p50 of mycoplasma hominis and to protein p89 of spiroplasma cit ...200212228289
tick-borne relapsing fever caused by borrelia turicatae.tick-borne relapsing fever manifests as relapsing episodes of fever with significant morbidity and mortality. we report a case of borrelia turicatae disease in a 13-year-old male youth with outdoor exposures in texas. after multiple clinic visits the diagnosis was made, and treatment was initiated. the patient did well without long term sequelae.200212237608
characterisation of silent and active genes for a variable large protein of borrelia recurrentis.we report the characterisation of the variable large protein (vlp) gene expressed by clinical isolate a1 of borrelia recurrentis; the agent of the life-threatening disease louse-borne relapsing fever.200212377101
decorin-binding proteins a and b confer distinct mammalian cell type-specific attachment by borrelia burgdorferi, the lyme disease spirochete.host cell binding is an essential step in colonization by many bacterial pathogens, and the lyme disease agent, borrelia burgdorferi, which colonizes multiple tissues, is capable of attachment to diverse cell types. glycosaminoglycans (gags) are ubiquitously expressed on mammalian cells and are recognized by multiple b. burgdorferi surface proteins. we previously showed that b. burgdorferi strains differ in the particular spectrum of gags that they recognize, leading to differences in the cultur ...200312773620
analysis of the ability of spirochete species associated with relapsing fever, avian borreliosis, and epizootic bovine abortion to bind factor h and cleave c3b.some borrelia species associated with lyme disease bind the complement-regulatory protein factor h (fh), a process that may aid in immune evasion. in this report we demonstrate that some borrelia species associated with relapsing fever bind fh, but not those associated with avian borreliosis and epizootic bovine abortion. cell-bound fh was also found to mediate cleavage of exogenously supplied human c3b, demonstrating the biological relevance of fh binding and its possible importance in the path ...200312904415
a novel, fast-growing borrelia sp. isolated from the hard tick hyalomma aegyptium in turkey.a novel, fast-growing spirochaete was isolated from the hard tick hyalomma aegyptium (family ixodidae, subfamily metastriata) using barbour-stoenner-kelly (bsk) ii medium. tick samples were taken during the summer of 2000 from the istanbul area in northwestern turkey. sixty-seven of 153 adults (44%) and 72 of 185 nymphs (39%) were infected with the novel spirochaete, whereas none of the 20 larvae examined were infected. the optimal growth temperature of the spirochaete in bsk ii medium was 34-37 ...200312949178
the cotton-rat as an experimental animal for spirochaeta turicatae brumpt. 195613337907
studies in borreliae. ii. some immunologic, biochemical and physical properties of the antigenic components of borrelia turicatae. 196514296302
infection and inflammation in skeletal muscle from nonhuman primates infected with different genospecies of the lyme disease spirochete borrelia burgdorferi.lyme borreliosis is a multisystemic disease caused by various genospecies of the spirochete borrelia burgdorferi. to investigate muscle involvement in the nonhuman primate (nhp) model of lyme disease, 16 adult macaca mulatta animals inoculated with strain n40 of b. burgdorferi sensu strictu by syringe or by tick bite or with strain pbi of b. burgdorferi genospecies garinii by syringe were studied. animals were necropsied while immunosuppressed on day 50 (two animals each inoculated with b. burgd ...200314638799
[aureomycin the treatment of human relapsing fever caused by spirochaeta turicatae]. 195014781538
cross-species surface display of functional spirochetal lipoproteins by recombinant borrelia burgdorferi.surface-exposed lipoproteins of relapsing fever (rf) and lyme borreliosis borrelia spirochetes mediate certain interactions of the bacteria with their arthropod and vertebrate hosts. rf spirochetes such as borrelia hermsii serially evade the host's antibody response by multiphasic antigenic variation of vsp and vlp proteins. furthermore, the expression of vsp1 and vsp2 by borrelia turicatae is associated with neurotropism and higher blood densities, respectively. in contrast to rf borrelia speci ...200414977951
isolation and characterization of borrelia hermsii associated with two foci of tick-borne relapsing fever in california.relapsing fever, caused by the spirochete borrelia hermsii and transmitted by the soft tick ornithodoros hermsi, is endemic in many rural mountainous areas of california. between 1996 and 1998, 12 cases of relapsing fever associated with two exposure sites in northern california were investigated. follow-up at exposure sites included collection of soft ticks and serum specimens from sylvatic rodents. attempts to cultivate spirochetes were made through inoculation of patient blood into mice and b ...200415004063
transgenic expression of reca of the spirochetes borrelia burgdorferi and borrelia hermsii in escherichia coli revealed differences in dna repair and recombination phenotypes.after unsuccessful attempts to recover a viable reca-deficient mutant of the lyme borreliosis agent borrelia burgdorferi, we characterized the functional activities of reca of b. burgdorferi, as well as reca of the relapsing fever spirochete borrelia hermsii and the free-living spirochete leptospira biflexa, in a reca mutant of escherichia coli. as a control, e. coli reca was expressed from the same plasmid vector. dna damage repair activity was assessed after exposure of the transgenic cells to ...200415060027
identification and characterization of a linear-plasmid-encoded factor h-binding protein (fhba) of the relapsing fever spirochete borrelia hermsii.in north america, tick-borne relapsing fever (tbrf) is caused by the spirochete species borrelia hermsii, borrelia parkeri, and borrelia turicatae. we previously demonstrated that some isolates of b. hermsii and b. parkeri are capable of binding factor h and that cell-bound factor h can participate in the factor i-mediated cleavage of c3b. isolates that bound factor h expressed a factor h-binding protein (fhbp) that we estimated to be approximately 19 to 20 kda in size and thus, pending further ...200415090501
glycerophosphodiester phosphodiesterase gene (glpq) of borrelia lonestari identified as a target for differentiating borrelia species associated with hard ticks (acari:ixodidae).a glpq ortholog was identified in dna from borrelia lonestari-positive amblyomma americanum, providing further evidence that b. lonestari is more closely related to the relapsing fever group spirochetes than to borreliae that cause lyme disease. this finding provides a basis for developing diagnostic assays to differentiate species of borrelia transmitted by hard ticks.200415131225
borrelia burgdorferi binds to, invades, and colonizes native type i collagen lattices.borrelia burgdorferi binds strongly to the extracellular matrix and cells of the connective tissue, a binding apparently mediated by specific proteins and proteoglycans. we investigated the interactions between b. burgdorferi cells and intact type i collagen using hydrated lattices that reproduce features of in vivo collagen matrices. b. burgdorferi cells of several strains adhered avidly to these acellular matrices by a mechanism that was not mediated by decorin or other proteoglycans. moreover ...200415155615
outer membrane proteins of pathogenic spirochetes.pathogenic spirochetes are the causative agents of several important diseases including syphilis, lyme disease, leptospirosis, swine dysentery, periodontal disease and some forms of relapsing fever. spirochetal bacteria possess two membranes and the proteins present in the outer membrane are at the site of interaction with host tissue and the immune system. this review describes the current knowledge in the field of spirochetal outer membrane protein (omp) biology. what is known concerning bioge ...200415449605
identification of a new borrelia species among small mammals in areas of northern spain where lyme disease is endemic.the role of small mammals as reservoir hosts for borrelia burgdorferi was investigated in several areas where lyme disease is endemic in northern spain. a low rate of infestation by ixodes ricinus nymphs was found in the small mammal populations studied that correlated with the near-absence of b. burgdorferi sensu lato in 184 animals tested and with the lack of transmission of b. burgdorferi sensu lato to i. ricinus larvae that fed on them. in contrast, questing ticks collected at the same time ...200515746336
improving the specificity of 16s rdna-based polymerase chain reaction for detecting borrelia burgdorferi sensu lato-causative agents of human lyme disease.16s rdna sequences of borrelia burgdorferi sensu lato were aligned with the 16s rdna sequences of borrelia hermsii, borrelia turicatae, and borrelia lonestari in order to identify primers that might be used to more specifically identify agents of human lyme disease in ticks in human skin samples.200515752343
'candidatus borrelia texasensis', from the american dog tick dermacentor variabilis.txw-1, a borrelia strain isolated in march 1998 from an adult male dermacentor variabilis tick feeding on a coyote from webb county, texas, usa, was characterized by using randomly amplified polymorphic dna (rapd) analysis, rflp and sequence analysis of flab and rrs (16s rrna gene), dna-dna hybridization analysis, sds-page and western blotting with mabs. it shows different banding patterns in rflp analysis of flab and forms distinct branches in phylogenetic analysis derived from flab and rrs gen ...200515774644
borrelia burgdorferi ospc heterogeneity among human and murine isolates from a defined region of northern maryland and southern pennsylvania: lack of correlation with invasive and noninvasive genotypes.b. burgdorferi invasiveness correlates with ospc genotype. to test this hypothesis and whether identical genotypes infect humans and small mammals in specific sites, b. burgdorferi ospc heterogeneity was tested among isolates from northern maryland and southern pennsylvania. six culture-positive patients allowed collection of small animals from their properties, and spirochetes from animals trapped within 300 yards of each patient's home were isolated. 3' ospc sequences were compared to referenc ...200515815012
relapsing fever spirochetes contain chromosomal genes with unique direct tandemly repeated sequences.genome sequencing of the relapsing fever spirochetes borrelia hermsii and borrelia turicatae identified three open reading frames (orfs) on the chromosomes that contained internal, tandemly repeated amino acid sequences that were absent in the lyme disease spirochete borrelia burgdorferi. the predicted amino acid sequences of these genes (bh0209, bh0512, and bh0553) have hydrophobic n termini, indicating that these proteins may be secreted. b. hermsii transcribed the three orfs in vitro, and the ...200515845510
bpta (bbe16) is essential for the persistence of the lyme disease spirochete, borrelia burgdorferi, in its natural tick vector.borrelia burgdorferi (bb), the agent of lyme disease, is a zoonotic spirochetal bacterium that depends on arthropod (ixodes ticks) and mammalian (rodent) hosts for its persistence in nature. the quest to identify borrelial genes responsible for bb's parasitic dependence on these two diverse hosts has been hampered by limitations in the ability to genetically manipulate virulent strains of bb. despite this constraint, we report herein the inactivation and genetic complementation of a linear plasm ...200515860579
phylogenetic analysis of the spirochetes borrelia parkeri and borrelia turicatae and the potential for tick-borne relapsing fever in florida.isolates of borrelia turicatae, borrelia parkeri, and the florida canine borrelia (fcb) were examined to further phylogenetically characterize the identities of these spirochetes in the united states. dna sequences of four chromosomal loci (the 16s rrna gene, flab, gyrb, and glpq) were determined for eight isolates of b. turicatae and six isolates of b. parkeri, which grouped the spirochetes into two distinct but closely related taxa (>98% sequence identity) separate from borrelia hermsii. the f ...200516081922
variable tick protein in two genomic groups of the relapsing fever spirochete borrelia hermsii in western north america.borrelia hermsii is the primary cause of tick-borne relapsing fever in north america. when its tick vector, ornithodoros hermsi, acquires these spirochetes from the blood of an infected mammal, the bacteria switch their outer surface from one of many bloodstream variable major proteins (vmps) to a unique protein, vtp (vsp33). vtp may be critical for successful tick transmission of b. hermsii; however, the gene encoding this protein has been described previously in only one isolate. here we ident ...200516177341
cardiac apoptosis in severe relapsing fever borreliosis.previous studies revealed that the heart suffers significant injury during experimental lyme and relapsing fever borreliosis when the immune response is impaired (d. cadavid, y. bai, e. hodzic, k. narayan, s. w. barthold, and a. r. pachner, lab. investig. 84:1439-1450, 2004; d. cadavid, t. o'neill, h. schaefer, and a. r. pachner, lab. investig. 80:1043-1054, 2000; and d. cadavid, d. d. thomas, r. crawley, and a. g. barbour, j. exp. med. 179:631-642, 1994). to investigate cardiac injury in borrel ...200516239571
fibronectin binding protein bbk32 of the lyme disease spirochete promotes bacterial attachment to glycosaminoglycans.borrelia burgdorferi, the agent of lyme disease, causes a multisystemic illness that can affect the skin, heart, joints, and nervous system and is capable of attachment to diverse cell types. among the host components recognized by this spirochete are fibronectin and glycosaminoglycans (gags). three surface-localized gag-binding bacterial ligands, bgp, dbpa, and dbpb, have been previously identified, but recent studies suggested that at least one additional gag-binding ligand is expressed on the ...200616368999
molecular analyses of the interaction of borrelia hermsii fhba with the complement regulatory proteins factor h and factor h-like protein 1.borrelia hermsii, the primary etiological agent of tick-borne relapsing fever in north america, binds the complement regulatory protein factor h (fh) as a means of evading opsonophagocytosis and the alternative complement pathway. the ability of fh-binding protein a (fhba) to bind fh-like protein 1 (fhl-1) has not been assessed previously. in this study, using a whole-cell absorption assay, we demonstrated that b. hermsii absorbs both fh and fhl-1 from human serum. consistent with this, affinity ...200616552029
serial determinations of platelet counts in mice by flow cytometry.elucidation of the pathophysiological basis of platelet disorders in murine models requires a reliable method for the frequent determinations of platelet counts in individual mice. here, we present a rapid, reproducible and accurate flow cytometric method for enumeration of platelets that involves fluorescent staining of platelets in whole blood with specific antibody and the addition of known numbers of fluorescent beads for standardization of the sample volume. analysis of platelets obtained b ...200111522020
extensive interplasmidic duplications change the virulence phenotype of the relapsing fever agent borrelia turicatae.the relapsing fever agent borrelia turicatae has two antigenically distinct serotypes, a and b, which differ in their variable small proteins (vsps) and in their degree of virulence and neurotropism in mice. each vsp gene (vspa or vspb) had an expression-linked copy that was unique to the serotype expressing it. this was located on one linear plasmid, which was defined by the upstream sequence. the archived copies of vspa and vspb were each located on different linear plasmids that were the same ...199910594835
borrelia recurrentis characterization and comparison with relapsing-fever, lyme-associated, and other borrelia spp.borrelia recurrentis, the cause of louse-borne relapsing fever, has until recently been considered noncultivable, which has prevented characterization of this spirochete. we successfully cultivated 18 strains from patients with louse-borne relapsing fever and present the initial characterization of these isolates. electron microscopy revealed spirochetal cells with pointed ends, an average wavelength of 1.8 microns, an amplitude of 0.8 micron, and 8 to 10 periplasmic flagella. the g+c ratio was ...19979336893
immunologic and genetic analyses of vmpa of a neurotropic strain of borrelia turicatae.in mice infected with serotype a but not serotype b of the relapsing fever spirochete borrelia turicatae, early invasion of the brain occurs. serotypes a and b are further distinguished by the abundant surface protein they produce: vmpa and vmpb, respectively. western blotting with monoclonal antibodies, one-dimensional peptide mapping, and partial amino acid sequencing demonstrated regions of the vmpa protein that differed from vmpb. oligonucleotide primers based on the partial amino acid seque ...19979234797
t-cell-independent elimination of borrelia turicatae.mice deficient or deprived of thymus-derived lymphocytes eliminated blood-borne borrelia turicatae with efficiency comparable to that observed in normal littermates. when challenged with 10(5) borreliae, nude mice had mean (+/- standard deviation) primary spirochetemias lasting 3.1 +/- 0.2 days and mean (+/- standard deviation) peak bacterial counts of 3.0 x 10(7) +/- 0.5 x 10(7) cells per ml of blood; in comparison, heterozygous littermates and normal mice had respective primary spirochetemias ...19846332075
antigenic variation of borrelia turicatae vsp surface lipoproteins occurs in vitro and generates novel serotypes.as a means of avoiding the host immune response, the tick-borne relapsing fever spirochete borrelia turicatae undergoes antigenic variation in its abundant surface lipoproteins. in this study, b. turicatae strain oz1, serotype b, was subcultured in vitro and cloned by limited dilutions after 50 passages. four different serotypes (serotypes a, b, e, and f) differing by their expressed vsp lipoproteins were isolated. using pulsed-field gel electrophoresis, we showed that the variability in surface ...200010724478
residual brain infection in relapsing-fever borreliosis.neurological involvement is common in the spirochetal infection relapsing fever (rf) in both humans and experimental animals. rf is best known for antigenic variation caused by the sequential expression of variable outer membrane lipoproteins of 2 sizes, variable small (vsp) and variable large (vlp) proteins. less understood is the persistence of rf borreliae in the brain after they are cleared from the blood, referred to as residual brain infection (rbi). our goal was to investigate the phenome ...200616619194
relapsing fever spirochaetes produce a serine protease that provides resistance to oxidative stress and killing by neutrophils.the spirochaetes that cause tick-borne relapsing fever and lyme disease are closely related human pathogens, yet they differ significantly in their ecology and pathogenicity. genome sequencing of two species of relapsing fever spirochaetes, borrelia hermsii and borrelia turicatae, identified a chromosomal open reading frame, designated bhpa, not present in the lyme disease spirochaete borrelia burgdorferi. the predicted amino acid sequence of bhpa was homologous with the htra serine proteases, w ...200616629672
crystal structure of neurotropism-associated variable surface protein 1 (vsp1) of borrelia turicatae.vsp surface lipoproteins are serotype-defining antigens of relapsing fever spirochetes that undergo multiphasic antigenic variation to allow bacterial persistence in spite of an immune response. two isogenic serotypes of borrelia turicatae strain oz1 differ in their vsp sequences and in disease manifestations in infected mice: vsp1 is associated with the selection of a neurological niche, while vsp2 is associated with blood and skin infection. we report here crystal structures of the vsp1 dimer ...200616740958
immunological and molecular analyses of the borrelia hermsii factor h and factor h-like protein 1 binding protein, fhba: demonstration of its utility as a diagnostic marker and epidemiological tool for tick-borne relapsing fever.it has been demonstrated that borrelia hermsii, a causative agent of relapsing fever, produces a factor h (fh) and fh-like protein 1 (fhl-1) binding protein. the binding protein has been designated fhba. to determine if fh/fhl-1 binding is widespread among b. hermsii isolates, a diverse panel of strains was tested for the fh/fhl-1 binding phenotype and fhba production. most isolates (23/24) produced fhba and bound fh/fhl-1. potential variation in fhba among isolates was analyzed by dna sequence ...200616861638
interaction of a neurotropic strain of borrelia turicatae with the cerebral microcirculation system.relapsing fever (rf) is a spirochetal infection characterized by relapses of a febrile illness and spirochetemia due to the sequential appearance and disappearance of isogenic serotypes in the blood. the only difference between isogenic serotypes is the variable major outer membrane lipoprotein. in the absence of specific antibody, established serotypes cause persistent infection. studies in our laboratory indicate that another consequence of serotype switching in rf is a change in neuroinvasive ...200616940140
identification of pathogenic leptospira species by conventional or real-time pcr and sequencing of the dna gyrase subunit b encoding gene.leptospira is the causative genus of the disease, leptospirosis. species identification of pathogenic leptospira in the past was generally performed by either dna-dna hybridisation or 16s rrna gene sequencing. both methods have inherent disadvantages such as the need for radio-labelled isotopes or significant homology between species. a conventional and real-time pcr amplification and sequencing method was developed for an alternate gene target: dna gyrase subunit b (gyrb). phylogenetic comparis ...200617067399
the mammalian host response to borrelia infection.tick-borne relapsing fever (rf) and lyme disease (ld) are spirochetal infections of humans caused by different borrelia species in endemic areas throughout the world. our laboratory is studying the response of mammalian hosts to borrelia infection in rf and ld. for this, we use mice and non-human primates infected with b. burgdorferi sensu stricto strain n40 (n40) and the oz1 strain of borrelia turicatae (bt), agents of ld and rf in north america, respectively. our results have revealed that out ...200617160603
role of interleukin 10 during persistent infection with the relapsing fever spirochete borrelia turicatae.relapsing fever is an infection characterized by peaks of spirochetemia attributable to antibody selection against variable serotypes. in the absence of b cells, serotypes cannot be cleared, resulting in persistent infection. we previously identified differences in spirochetemia and disease severity during persistent infection of severe combined immunodeficiency mice with isogenic serotypes 1 (bt1) or 2 (bt2) of borrelia turicatae. to investigate this further, we studied pathogen load, clinical ...200717200198
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