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S W Barthold

Publications and source records attributed to S W Barthold.

At least 73 records · Page 4Linked to original sources
PubMed1996

Novel Borrelia burgdorferi isolates from Ixodes scapularis and Ixodes dentatus ticks feeding on humans.

Seven cultures of Borrelia burgdorferi differing from strains B31 and ZS7 were identified from among 99 isolates from Ixodes scapularis ticks and from white-footed mice (Peromyscus leucopus) and 1 isolate from an Ixodes dentatus tick. Five of the six novel isolates from I. scapularis and the isolate from I. dentatus were from ticks feeding on humans. The six isolates from I. scapularis lacked OspA and OspB, four possessed an OspD band, and two reacted with an anti-OspC monoclonal antibody. Restriction fragment length polymorphisms of HindIII-digested DNAs from six OspA-negative isolates did not hybridize with radiolabeled ospA or LA88 DNA, and only isolate 46047 hybridized with the pG gene. Fragments similar to those recorded for the standard B. burgdorferi sensu stricto strains B31 and ZS7 were obtained with the fla and the HSP70 genes. Pulsed-field gel electrophoresis patterns of DNA digested with MluI included the specific B. burgdorferi sensu stricto band at 135 kbp for the five OspA-negative isolates from I. scapularis ticks. The six novel isolates apparently lack the 55-kbp plasmid encoding OspA. The pG-containing plasmid may be missing from all but isolate 46047. The isolate from the I. dentatus tick was similar to previous isolates from I. dentatus ticks feeding on rabbits. None of the isolates could be recovered from inoculated C3H/HeNCrlBR or white-footed mice. All isolates reacted with sera from humans with early or late Lyme disease. Our studies demonstrate that these borreliae occur in ticks feeding on humans, and therefore, at least some humans in the northeastern United States are likely being exposed to borreliae other than the classic B31-type strains that have thus far been isolated from humans.

Animals↗
PubMed1996

Serum-mediated resolution of Lyme arthritis in mice.

Arthritis and carditis were mildly improved upon adoptive transfer of T cell enriched lymphocyte populations from Borrelia burgdorferi-infected (B. burgdorferi) (immune) compared with naive immunocompetent mice into B. burgdorferi-infected, severe combined immunodeficient (SCID) mice. Despite the relative purity of T cells in transferred cells, recipient mice seroconverted to B. burgdorferi. Thus, the effect could not be attributed to T cells alone. Passive transfer of serum from actively infected immunocompetent mice (immune serum) to SCID mice at the time of or before B. burgdorferi inoculation, or on Days 4, 8, and 12 after inoculation prevented or cured (respectively) infection and disease when examined at 15 days. Transfer of immune serum on Days 12, 16, 20, 24, and 28 did not clear infection at Day 30 but resulted in resolution of arthritis, indicating that immune serum can cause resolution of joint disease. Immune serum treatment could maintain arthritis resolution for up to 60 days. Immune serum from mice infected for 90 days or 15 months both had strong protective, post-infection, and arthritis-modulating activity, whereas hyperimmune serum to heat-killed B. burgdorferi or recombinant outer surface protein (Osp) A protected mice against infection when given on Day 0--but not at later intervals--and did not modulate disease. Immune serum from 90-day infected mice labeled spirochetes in joint tissues of SCID mice by immunohistochemistry, but hyperimmune serum to heat-killed B. burgdorferi or OspA did not. These studies suggest that the biologically active properties of immune serum may be directed toward yet to be defined, in vivo-expressed antigens of B. burgdorferi.

Animals↗
PubMed1995

An ospA frame shift, identified from DNA in Lyme arthritis synovial fluid, results in an outer surface protein A that does not bind protective antibodies.

Passive immunization with murine or human Abs to outer surface protein A (OspA) can protect mice against Borrelia burgdorferi, but OspA Abs elicited during natural infection in mice or humans are unable to clear the spirochete from the infected host. To examine Ab binding by OspA during the course of human infection, we amplified the operon encoding full-length ospA and ospB from synovial fluids of a patient with chronic Lyme arthritis, the first such recoveries from human material, at four separate time points over 4.5 mo, and expressed OspA in Escherichia coli. OspA mAbs that passively protected mice from infection did not bind one of the expressed OspAs, because of a deletion in ospA that resulted in a frame shift and premature stop codon near the carboxyl terminus. However, expressed OspA from a later synovial fluid sample did not contain this deletion. Thus, although altered forms of OspA, which potentially can influence host immune effectiveness, do occur in the human host, they cannot be the only factors responsible for microbial persistence.

Adolescent↗
PubMed1995

Serologic responses of dogs naturally exposed to or vaccinated against Borrelia burgdorferi infection.

OBJECTIVE: To characterize the serologic responses of dogs naturally exposed to or vaccinated against Borrelia burgdorferi and to assess responses at intervals after antibiotic treatment. DESIGN: Prospective, controlled clinical trial. ANIMALS: 19 dogs of various breeds and ages with narrowly defined clinical criteria of limb/joint borreliosis and 10 control dogs of equivalent age were used to determine serologic responses following natural exposure to the organism. Eight seronegative dogs were used to determine serologic responses following vaccination. PROCEDURE: Serologic responses to B burgdorferi and recombinant outer surface protein (Osp)A, flagellin, and P39 were assessed by means of ELISA and western immunoblot. Passive protective activity was assessed by use of a mouse protection assay. RESULTS: Naturally exposed dogs were seropositive, but had variable ELISA titers and immunoblot profiles. Immunoblot analysis did reveal consistent reactions to flagellin, P39, and a 22 kd protein, but not to OspA. Antibody responses did not change appreciably up to 13 weeks after antibiotic treatment. Vaccinated dogs had strong reactions to OspA and OspB, but not to P39. CLINICAL IMPLICATIONS: Dogs with clinical borreliosis are seropositive and remain seropositive after antibiotic treatment, emphasizing that serologic testing is not a useful means of measuring clinical response. Serologic responses of infected dogs can be discriminated from those of vaccinated dogs by means of immunoblot analysis, and recombinant P39 is a potentially useful antigen for that purpose.

Animals↗
PubMed1995

Borrelia burgdorferi genes selectively expressed in the infected host.

An immunological screening strategy was used to select microbial genes expressed only in the host. Differential screening of a Borrelia burgdorferi (the Lyme disease agent) expression library identified a gene (p21) encoding a 20.7-kDa antigen that reacted with antibodies in serum from actively infected mice but not serum from mice immunized with heat-killed B. burgdorferi. Selective expression of p21 in the infected host was confirmed by Northern blot analysis and RNA PCR. Further differential screening of the expression library identified at least five additional B. burgdorferi genes are selectively expressed in vivo. This screening method can be used to identify genes induced in vivo in a wide variety of pathogenic microorganisms for which a gene transfer system is not currently available.

Amino Acid Sequence↗
PubMed1995

Vaccination against Lyme disease caused by diverse Borrelia burgdorferi.

Diversity and mutations in the genes for outer surface proteins (Osps) A and B of Borrelia burgdorferi sensu lato (B. burgdorferi), the spirochetal agent of Lyme disease, suggests that a monovalent OspA or OspB vaccine may not provide protection against antigenically variable naturally occurring B. burgdorferi. We now show that OspA or OspB immunizations protect mice from tick-borne infection with heterogeneous B. burgdorferi from different geographic regions. This result is in distinct contrast to in vitro killing analyses and in vivo protection studies using syringe injections of B. burgdorferi as the challenge inoculum. Evaluations of vaccine efficacy against Lyme disease and other vector-borne infections should use the natural mode of transmission and not be predicated on classification systems or assays that do not rely upon the vector to transmit infection.

Animals↗
PubMed1995

Efficacy of human Lyme disease vaccine formulations in a mouse model.

Although immunization with recombinant outer surface protein A (OspA) appears to protect mice against infection by the agent of Lyme disease, all reported experiments have involved formulations that would not be suitable for use in humans or have not used realistic challenges. This study was designed to determine whether vaccines prepared and used in a phase I human trial, including one currently being used for a phase II trial in sites with endemic Borrelia burgdorferi, conferred protection in the C3H/HeJ mouse model. The challenge was ticks collected from a major site of the trial. None of the vaccinated mice became infected or developed disease, whereas 60% of unvaccinated mice became infected. Spirochetes were destroyed within the guts of virtually all recovered challenge ticks. These preparations of recombinant OspA effectively induced immunity to protect mice from Lyme disease when bitten by ticks collected from a field trial site.

Adjuvants, Immunologic↗
PubMed1995

Lyme disease in human DR4Dw4-transgenic mice.

The evolution of Lyme arthritis in DR4-transgenic mice infected with Borrelia burgdorferi was studied because chronic Lyme arthritis in humans is associated with an increased frequency of the HLA-DR4 allele. B10 nontransgenic and DR4-transgenic mice expressing chimeric human-mouse major histocompatibility complex class II genes in which the human alpha 1 and beta 1 domains of DR4Dw4 replaced the corresponding domains of the mouse I-E(d) were inoculated with B. burgdorferi and examined at up to 180 days for infection and disease. All mice were infected throughout the 180 days, and arthritis evolved to equal severity in transgenic and control mice within 30 days and resolved by day 120. Both groups of mice developed high antibody titers to B. burgdorferi, but antibodies to outer surface proteins A and B were not readily detectable. The DR4Dw4 transgene did not predispose mice to the development of chronic Lyme arthritis.

Alleles↗
PubMed1995

Exacerbation of Lyme arthritis in beige mice.

Borrelia burgdorferi-induced disease susceptibility was explored in disease-resistant C57/BL6 (B6) and -susceptible C3H/He (C3H) mice with and without the beige (bg) mutation, which is associated with granulocyte and NK cell dysfunction. Both B6 and C3H mice had more prevalent and severe arthritis than their congenic partners, and B6-bg mice developed arthritis equal in severity to that in C3H mice. Spirochetes were visualized in joint tissue of B6-bg mice but not B6 mice. No differences in spirochete isolation from tissues or immunoglobin titers to B. burgdorferi were noted between groups. Depletion of granulocytes with cyclophosphamide and macrophages with silica in B6 and C3H mice modified arthritis susceptibility, but depletion of NK cells by serotherapy in B6 mice had no effect on disease. This study demonstrates that innate genetic resistance to Lyme arthritis in mice can be overcome by a single gene mutation, which is probably mediated through granulocyte function.

Animals↗
PubMed1995

Oral vaccination with an attenuated Salmonella typhimurium strain expressing Borrelia burgdorferi OspA prevents murine Lyme borreliosis.

Borrelia burgdorferi is the causative agent of Lyme disease. In the mouse model, protection is correlated with the development of antibodies to a major outer surface protein, OspA. In this study, we expressed OspA in an attenuated strain of Salmonella typhimurium and tested the efficacy of the transformed strain in protecting against disease. We show that mice inoculated by gavage developed high titers of anti-OspA antibodies and were protected against an intradermal challenge with the spirochete.

Administration, Oral↗
PubMed1995

Selection of variant Borrelia burgdorferi isolates from mice immunized with outer surface protein A or B.

A nonclonal population of Borrelia burgdorferi N40 (passage 3) that survived protective immunity following challenge inoculation of outer surface protein (Osp) A- or B-hyperimmunized mice were characterized for the molecular basis of evasion of immunity. Two of six B. burgdorferi isolates, cultured from OspA-immunized mice, had antigenic diversity in the carboxyl terminus of OspA and did not bind to the protective OspA monoclonal antibody designated IXDII. However, OspA-immunized mice challenged with these variants were fully protected. Moreover, B. burgdorferi isolates with a point mutation in ospB, which results in a truncated OspB that does not bind to protective OspB monoclonal antibody 7E6C, were frequently enriched after infection of OspB-immunized mice. These studies suggest that the incomplete efficacy of an OspA- or OspB-based vaccine may be partly due to immunomediated in vivo selective pressure, resulting in the persistence of some spirochetes that do not bind to protective antibodies.

Animals↗
PubMed1995

Circumvention of outer surface protein A immunity by host-adapted Borrelia burgdorferi.

Outer surface protein A (OspA), which is abundantly expressed in cultured Borrelia burgdorferi, appears to be down-regulated or masked following low-dose infection, and OspA immunization did not prevent infection, dissemination, or disease development with host-adapted spirochetes. Seroconversion of mice to B. burgdorferi OspA depended on dose and viability of inoculated spirochetes. Mice inoculated with > 10(4) live spirochetes and > 10(7) heat-killed spirochetes seroconverted to OspA, but mice inoculated with fewer spirochetes did not seroconvert to OspA at 2 weeks after inoculation. Growth temperature of spirochetes was not a factor for infectious dose or seroconversion to OspA. Spirochetes grown at 30, 34, or 38 degrees C had the same median infectious dose. Growth temperature did not influence infectious dose when mice were inoculated intraperitoneally or intradermally and did not influence dose-related immunologic recognition of OspA. Mice hyperimmunized with recombinant OspA-glutathione S-transferase (GT) fusion protein or GT (controls) were challenged by syringe inoculation with 10(3) spirochetes or by transplantation of infected skin from syngenic mice infected for 2 or 8 weeks. OspA-GT-immunized mice resisted syringe challenge but developed disseminated infections following transplantation of infected skin. Identical results were obtained in mice passively immunized with hyperimmune serum to OspA-GT or GT and then challenged by syringe or infected skin transplant. The number of spirochetes in infected skin, determined by quantitative PCR directed toward both plasmid and genomic targets, was less than the syringe challenge dose.

Adaptation, Physiological↗
PubMed1995

Lyme borreliosis in transgenic mice tolerant to Borrelia burgdorferi OspA or B.

The evolution of Lyme borreliosis in transgenic mice tolerant to Borrelia burgdorferi outer surface proteins (Osps) A or B was assessed to investigate the role of immunity to OspA or B in infection and pathogenesis of Lyme disease. Antibodies to OspA or B protect immunocompetent C3H/HeJ or C.B.17 severe combined immunodeficient (scid) mice from challenge with B. burgdorferi. Moreover, arthritis in infected C3H mice resolves with the rise of high titers of B. burgdorferi specific antibodies, including OspA and B, whereas disease persists in scid mice--suggesting that the regression of arthritis may be due to the development of borreliacidal OspA or B antibodies. To evaluate the course of Lyme borreliosis in OspA or B tolerant mice we developed transgenic mice that expressed OspA or B under control of the major histocompatibility complex (MHC) class I promoter. Mice carrying OspA or B transgenes on a C3H/HeJ (C3H, disease-susceptible) or C57BL/6 (B6, disease-resistant) background, immunized with OspA or B, did not mount a humoral or cellular immune response to OspA or B, respectively, but responded normally to other B. burgdorferi antigens. The evolution of Lyme borreliosis, including infection and the development of arthritis and carditis, was similar in transgenic and nontransgenic littermates suggesting that an OspA or B immune response is not singularly involved in either the genesis or regression of Lyme disease in C3H or B6 mice.

Animals↗