Lyme Borreliosis in Rhesus Macaques: Effects of Corticosteroids on Spirochetal Load and Isotype Switching of Anti-Borrelia burgdorferi Antibody

Experimental Borrelia burgdorferi infection of rhesus monkeys is an excellent model of Lyme disease and closely parallels the infection in humans. Little is known about the interaction of host immunity with the spirochete in patients with chronic infection. We hypothesized that rapid development of anti-B. burgdorferi antibody in immunocompetent nonhuman primates (NHPs) is the major determinant of the reduction of the spirochetal load in Lyme borreliosis. This hypothesis was tested by measurement of the spirochetal load by PCR in association with characterization of the anti-B. burgdorferi humoral immune response in immunocompetent NHPs versus that in corticosteroid-treated NHPs. Although anti-B. burgdorferi immunoglobulin G (IgG) antibody was effectively inhibited in dexamethasone (Dex)-treated NHPs, anti-B. burgdorferi IgM antibody levels continued to rise after the first month and reached levels in excess of IgM levels in immunocompetent NHPs. This vigorous production of anti-B. burgdorferi IgM antibodies was also studied in vitro by measurement of antibody produced by B. burgdorferi-stimulated peripheral blood mononuclear cells. Despite these high IgM antispirochetal antibodies in Dex-treated NHPs, spirochetal loads were much higher in these animals. These data indicate that Dex treatment results in interference with isotype switching in this model and provide evidence that anti-B. burgdorferi IgG antibody is much more effective than IgM antibody in decreasing the spirochetal load in infected animals.     

Specificity of Infection-Induced Immunity among Borrelia burgdorferi Sensu Lato Species

The specificity of infection-induced immunity in mice infected with cultured or host-adapted Borrelia burgdorferi sensu lato, the agent of Lyme disease, was examined. Sera obtained from mice following infection with high and low doses of cultured B. burgdorferi sensu stricto, transplantation of infected tissue (host-adapted spirochetes), or tick-borne inoculation all showed protective activity in passive immunization assays. Infection and disease were similar in mice infected with cultured spirochetes or by transplantation. Thus, the adaptive form of inoculated spirochetes did not influence the immune response during active infection. Mice infected with B. burgdorferi sensu stricto and then cured of infection with an antibiotic during early or late stages of infection were resistant to challenge with high doses of homologous cultured spirochetes for up to 1 year. In contrast, actively immune mice infected with different Borrelia species (B. burgdorferi sensu lato, B. burgdorferi sensu stricto cN40, Borrelia afzelii PKo, and Borrelia garinii PBi) and then treated with an antibiotic were resistant to challenge with cultured homologous but not heterologous spirochetes. Similar results were achieved for actively immune mice challenged by transplantation and by passive immunization with sera from mice infected with each of the Borrelia species and then challenged with cultured spirochetes. Arthritis and carditis in mice that had immunizing infections with B. afzelii and B. garinii and then challenged by transplantation with B. burgdorferi sensu stricto were equivalent in prevalence and severity to those in nonimmune recipient mice. These results indicate that protective immunity and disease-modulating immunity that develop during active infection are universal among species related to B. burgdorferi sensu lato but are species specific.     

DbpA, but Not OspA, Is Expressed by Borrelia burgdorferi during Spirochetemia and Is a Target for Protective Antibodies

DbpA is a target for antibodies that protect mice against infection by cultured Borrelia burgdorferi. Infected mice exhibit early and sustained humoral responses to DbpA and DbpB, suggesting that these proteins are expressed in vivo. Many antigens expressed in mammals by B. burgdorferi are repressed in vitro at lower growth temperatures, and we have now extended these observations to include DbpA and DbpB. To confirm that the protective antigen DbpA is expressed in vivo and to address the question of its accessibility to antibodies during infection, we examined B. burgdorferi in blood samples from mice following cutaneous inoculation. B. burgdorferi was visualized by dark-field microscopy in plasma samples from spirochetemic mice, and an indirect immunofluorescence assay showed that these spirochetes were DbpA positive and OspA negative. We developed an ex vivo borreliacidal assay to show that hyperimmune antiserum against DbpA, but not OspA, killed these plasma-derived spirochetes, demonstrating that DbpA is accessible to antibodies during this phase of infection. Blood transferred from spirochetemic donor mice readily established B. burgdorferi infection in naive recipient mice or mice hyperimmunized with OspA, while mice hyperimmunized with DbpA showed significant protection against challenge with host-adapted spirochetes. Antiserum from persistently infected mice had borreliacidal activity against both cultured and plasma-derived spirochetes, and adsorption of this serum with DbpA substantially depleted this killing activity. Our observations show that immunization with DbpA blocks B. burgdorferi dissemination from the site of cutaneous inoculation and suggest that DbpA antibodies may contribute to control of persistent infection.     

Persistence of borrelial DNA in the joints of Borrelia burgdorferi‐infected mice after ceftriaxone treatment

Yrjänäinen H, Hytönen J, Hartiala P, Oksi J, Viljanen MK. Persistence of borrelial DNA in the joints of Borrelia burgdorferi‐infected mice after ceftriaxone treatment. APMIS 2010; 118: 665–73. We have earlier shown that Borrelia burgdorferi‐infected and ceftriaxone‐treated mice have viable spirochetes in their body, since immunosuppressive treatment allows B. burgdorferi to be detected by culture. However, the niche of the persisting spirochetes remained unknown. In the present study, we analyzed the tissues of B. burgdorferi‐infected and ceftriaxone‐treated mice by culture and PCR to reveal the foci of persisting spirochetes. C3H/HeN mice were infected via intradermal needle injection with B. burgdorferi s.s. N40. The mice were treated as follows: (i) short (5 days) and (ii) long (18 days) course of ceftriaxone at 2 weeks of infection and killed after either 10 or 30 weeks, or (iii) the mice received ceftriaxone for 5 days at 18 weeks of infection and were killed 21 weeks after the treatment. All samples of ceftriaxone‐treated mice were culture negative, whereas all untreated controls were culture positive. Importantly, B. burgdorferi DNA was detected in the joints of 30–100% of the treated mice. In conclusion, these results combined with earlier results suggest that the joint or a tissue adjacent to the joint is the niche of persisting B. burgdorferi in ceftriaxone‐treated mice.     

Antibodies to Borrelia burgdorferi OspA, OspC, OspF, and C6 Antigens as Markers for Early and Late Infection in Dogs

Lyme disease in the United States is caused by Borrelia burgdorferi sensu stricto, which is transmitted to mammals by infected ticks. Borrelia spirochetes differentially express immunogenic outer surface proteins (Osp). Our aim was to evaluate antibody responses to Osp antigens to aid the diagnosis of early infection and the management of Lyme disease. We analyzed antibody responses during the first 3 months after the experimental infection of dogs using a novel multiplex assay. Results were compared to those obtained with two commercial assays detecting C6 antigen. Multiplex analysis identified antibodies to OspC and C6 as early as 3 weeks postinfection (p.i.) and those to OspF by 5 weeks p.i. Antibodies to C6 and OspF increased throughout the study, while antibodies to OspC peaked between 7 and 11 weeks p.i. and declined thereafter. A short-term antibody response to OspA was observed in 3/8 experimentally infected dogs on day 21 p.i. Quant C6 enzyme-linked immunosorbent assay (ELISA) results matched multiplex results during the first 7 weeks p.i.; however, antibody levels subsequently declined by up to 29%. Immune responses then were analyzed in sera from 125 client-owned dogs and revealed high agreement between antibodies to OspF and C6 as robust markers for infection. Results from canine patient sera supported that OspC is an early infection marker and antibodies to OspC decline over time. The onset and decline of antibody responses to B. burgdorferi Osp antigens and C6 reflect their differential expression during infection. They provide valuable tools to determine the stage of infection, treatment outcomes, and vaccination status in dogs.     

Genospecies Identification and Characterization of Lyme Disease Spirochetes of Genospecies Borrelia burgdorferi Sensu Lato Isolated from Rodents in Taiwan

Lyme disease spirochetes of the genospecies Borrelia burgdorferi sensu lato were identified and characterized for the first time in Taiwan. Seven isolates, designated TWKM1 to TWKM7, were purified from the ear tissues of three species of rodents captured from seven localities of Taiwan. The immunological characteristics of these Taiwan isolates were compared with those of other genospecies of Lyme disease spirochetes by analyzing the protein profiles and reactivities with B. burgdorferi-specific monoclonal antibodies (MAbs). The genospecies of these Taiwan isolates were also identified by the similarities in their plasmid profiles and differential reactivities with genospecies-specific PCR primers. Although two distinct protein profiles were observed among the seven Taiwan isolates, the MAb reactivities against the outer surface proteins of B. burgdorferi of all of these isolates were consistent with those of B. burgdorferi sensu lato. The similarities of the plasmid profiles also confirmed the identities of these Taiwan isolates. PCR analysis indicated that all of these Taiwan isolates were genetically related to the genospecies B. burgdorferi sensu stricto. These results demonstrate the first identification of Lyme disease spirochetes in Taiwan and also highlight the increasing demand for defining the reservoirs and vector ticks of B. burgdorferi. A serosurvey for Lyme disease infection in the human population of Taiwan may also be required.     

Influence of Outer Surface Protein A Antibody on Borrelia burgdorferi within Feeding Ticks

Borrelia burgdorferi, the spirochetal agent of Lyme disease, is transmitted by Ixodes ticks. When an infected nymphal tick feeds on a host, the bacteria increase in number within the tick, after which they invade the tick’s salivary glands and infect the host. Antibodies directed against outer surface protein A (OspA) of B. burgdorferi kill spirochetes within feeding ticks and block transmission to the host. In the studies presented here, passive antibody transfer experiments were carried out to determine the OspA antibody titer required to block transmission to the rodent host. OspA antibody levels were determined by using a competitive enzyme-linked immunosorbent assay that measured antibody binding to a protective epitope defined by monoclonal antibody C3.78. The C3.78 OspA antibody titer (>213 μg/ml) required to eradicate spirochetes from feeding ticks was considerably higher than the titer (>6 μg/ml) required to block transmission to the host. Although spirochetes were not eradicated from ticks at lower antibody levels, the antibodies reduced the number of spirochetes within the feeding ticks and interfered with the ability of spirochetes to induce ospC and invade the salivary glands of the vector. OspA antibodies may directly interfere with the ability of B. burgdorferi to invade the salivary glands of the vector; alternately, OspA antibodies may lower the density of spirochetes within feeding ticks below a critical threshold required for initiating events linked to transmission.     

Humoral Immune Response Associated with Lyme Borreliosis in Nonhuman Primates: Analysis by Immunoblotting and Enzyme-Linked Immunosorbent Assay with Sonicates or Recombinant Proteins

The immune response to Borrelia burgdorferi, the causative agent of Lyme disease, is complex. We studied the immunoglobulin M (IgM) and IgG antibody response to N40Br, a sensu stricto strain, in the rhesus macaque(nonhuman primate [NHP]) model of infection to identify the spirochetal protein targets of specific antibody. Antigens used in enzyme-linked immunosorbent assays were whole-cell sonicates of the spirochete and recombinant proteins of B. burgdorferi. Immunoblotting with a commercially available strip and subsequent quantitative densitometry of the bands were also used. Sera from four different groups of NHPs were used: immunocompetent, transiently immunosuppressed, extended immunosuppressed, and uninfected. In immunocompetent and transiently immunosuppressed NHPs, there was a strong IgM and IgG response. Major proteins for the early IgM response were P39 and P41 and recombinant BmpA and OspC. Major proteins for the later IgG response were P39, P41, P18, P60, P66, and recombinant BmpA and DbpA. There was no significant response in the NHPs to recombinant OspA or to Arp, a 37-kDa protein that elicits an antibody response during infection in mice. Most antibody responses, except for that to DbpA, were markedly diminished by prolonged dexamethasone treatment. This study supports the hypothesis that recombinant proteins may provide a useful adjunct to current diagnostic testing for Lyme borreliosis.     

Gamma Interferon Inhibits Production of Anti-OspA Borreliacidal Antibody In Vitro

The ability of a Lyme borreliosis vaccine to induce and maintain sustained levels of borreliacidal antibody is necessary for prolonged protection against infection with Borrelia burgdorferi. Vaccination against infection with B. burgdorferi could be improved by determining the mechanism(s) that influences the production of protective borreliacidal antibody. Borreliacidal antibody was inhibited in cultures of lymph node cells obtained from C3H/HeJ mice vaccinated with formalin-inactivated B. burgdorferi and cultured with macrophages and B. burgdorferi and treated with recombinant gamma interferon (rIFN-γ). The suppression of production of outer surface protein A (OspA) borreliacidal antibody by rIFN-γ was not affected by the time of treatment. In addition, treatment with rIFN-γ inhibited the production of other anti-B. burgdorferi antibodies. By contrast, treatment of cultures of immune lymph node cells with anti-IFN-γ marginally increased the production of borreliacidal antibody and enhanced the production of other antibodies directed against B. burgdorferi. These results show that IFN-γ does not play a major role in the production of anti-OspA borreliacidal antibody. Additional studies are needed to determine which cytokine(s) will enhance production of borreliacidal antibody.     

Borrelia burgdorferi Linear Plasmid 28-3 Confers a Selective Advantage in an Experimental Mouse-Tick Infection Model

Borrelia burgdorferi, the bacterium that causes Lyme disease, has a unique segmented genome consisting of numerous linear and circular plasmids and a linear chromosome. Many of these genetic elements have been found to encode factors critical for B. burgdorferi to complete the infectious cycle. However, several plasmids remain poorly characterized, and their roles during infection with B. burgdorferi have not been elucidated. To more fully characterize the role of one of the four 28-kb linear plasmids, lp28-3, we generated strains specifically lacking lp28-3 and assayed the contribution of genes carried by lp28-3 to B. burgdorferi infection. We found that lp28-3 does not carry any genes that are strictly required for infection of a mouse or tick and that lp28-3-deficient spirochetes are competent at causing a disseminated infection. Interestingly, spirochetes containing lp28-3 were at a selective advantage compared to lp28-3-deficient spirochetes when coinjected into a mouse, and this advantage was reflected in the population of spirochetes acquired by feeding ticks. Our data demonstrate that genes carried by lp28-3, although not essential, contribute to the fitness of B. burgdorferi during infection.     

Efficiency of experimental infection of Ixodes ricinus ticks with Borrelia burgdorferi spirochetes

Feeding of an ixodid tick on a Borrelia-infected vertebrate is the natural route of tick infection. To obtain a cohort of nymphs with a high prevalence of infection, the immersion of Ixodes ricinus larvae in the suspension of B. burgdorferi sensu stricto spirochetes was used. Immersed larvae fed on C3H mice until full engorgement, molted to nymphs and 9 of 10 nymphs were shown to be infected by PCR with specific primers. Specific antibodies in the sera of the mice, on which either immersion-infected larvae or infected nymphs had engorged, were not detected. However, nymphs molted from immersed larvae were able to infect naïve mice, and all the resulting 10 adults were infected.     

The chemokine CXCL13 in cerebrospinal fluid in children with Lyme neuroborreliosis

Anti-Borrelia antibodies in the cerebrospinal fluid (CSF) are required for definite diagnosis of Lyme neuroborreliosis (LNB). However, children often present with early LNB, and antibody production in the CSF may not be demonstrated. Recent studies have suggested the chemokine CXCL13 to be an early marker for LNB. The aim of the study was to evaluate CXCL13 for laboratory diagnosis in pediatric LNB patients and to evaluate the association with pleocytosis in CSF, clinical features, and recovery. CSF samples were collected from LNB patients, classified as definite LNB (n?=?44) or possible LNB (n?=?22), and controls classified as non-LNB (n?=?102) or other specific diagnoses (n?=?23). CSF samples were analyzed with the recomBead CXCL13 assay (Mikrogen Diagnostik, Germany), cut-off 160 pg/mL. CXCL13 was significantly higher in LNB patients compared to controls (p?<?0.001). Among LNB patients, 58/66 had elevated CXCL13, and among controls, 111/125 had CXCL13 levels under cut-off (sensitivity 88%, specificity 89%). In LNB patients with pleocytosis but no detectable anti-Borrelia antibodies in CSF (possible LNB), CXCL13 was elevated in 16/22 (73%). A weak correlation between CXCL13 and pleocytosis in CSF was found in LNB patients (Rho?=?0.46, p?<?0.01), but no differences in CXCL13 levels in relation to specific clinical features. In conclusion, CXCL13 is elevated in CSF in children with LNB, showing acceptable sensitivity and specificity. In patients with possible LNB, CXCL13 was elevated in a majority of cases (73%) and is suggested as a complementary diagnostic tool in pediatric LNB patients. CXCL13 was not associated with specific clinical features or recovery.     

Experimental infection of dogs with<Emphasis Type="Italic"> Borrelia burgdorferi</Emphasis> sensu stricto using<Emphasis Type="Italic"> Ixodes scapularis</Emphasis> ticks artificially infected by capillary feeding

Specific pathogen-free dogs were experimentally infected with Borrelia burgdorferi sensu stricto using nymphal or adult female Ixodes scapularis ticks artificially infected with spirochetes by capillary feeding. The ticks were capillary fed B. burgdorferi isolate 610, previously isolated from a dog with Lyme disease and grown in BSK medium. This isolate induced clinical signs in the dogs similar to those for dogs infested with ticks naturally infected with B. burgdorferi. Adult ticks were more efficient than nymphs in transmitting spirochetes to the dogs. One of five dogs infested with nymphal ticks capillary fed B. burgdorferi was skin biopsy culture and serologically positive, and demonstrated lameness. In contrast, all five dogs infested with adult female ticks that had been capillary fed with B. burgdorferi were culture and serologically positive, with one dog developing lameness. The immunoblot profiles of dogs challenged with female ticks infected by capillary feeding (8 weeks post challenge) were similar to immunoblots (4 weeks post challenge) from dogs challenged with naturally infected females collected in the field. These studies demonstrated that B. burgdorferi cultured in BSK medium can be capillary fed to either nymphal or adult female ticks under laboratory controlled conditions for the purpose of transmitting the spirochete to dogs during the tick's blood meal. This tick infection system would be useful for a controlled and defined challenge of vaccinated and non-vaccinated dogs for proper evaluation of vaccine efficacy, which is difficult to achieve using field-collected ticks. Furthermore, this system may also be useful for investigation of the pathogenesis of Lyme disease, evaluation of the pathogenicity of new isolates of B. burgdorferi, or evaluation of antibiotic therapy.     

Protection from Lyme Neuroborreliosis in Nonhuman Primates with a Multiantigenic Vaccine

In an effort to develop an effective and safe vaccine for lyme disease, rhesus macaques were injected with a multiantigenic preparation of Borrelia burgdorferi, strain N40. One month later animals were boosted before intradermal challenge with infectious B. burgdorferi. Challenges were performed at 1 and again at 5 months after the booster vaccination. Vaccinated and control nonvaccinated animals were monitored for development of systemic infection by measurement of serum anti-spirochetal antibodies by ELISA and Western blotting, and neurological involvement was monitored by testing of cerebrospinal fluid (CSF) and PCR analysis of central nervous system (CNS) tissue obtained at necropsy. Two control nonhuman primates (NHPs), given saline injections instead of vaccine and then challenged with B. burgdorferi, developed CSF pleocytosis, PCR positivity of the brain, and high levels of specific anti-B. burgdorferi antibody in the serum and CSF. Necropsy studies revealed widespread invasion of the CNS of one of these animals by the spirochete. In contrast, none of the four vaccinated animals developed evidence of invasion of the CNS after either of two challenge inoculations with infectious B. burgdorferi. In addition to resisting infection, no vaccinated animal demonstrated any untoward consequence of vaccination. These data demonstrate that a multiantigenic vaccine is effective in preventing systemic infection and lyme neuroboreliosis in NHPs and suggest that a successful vaccine could be developed in humans which would prevent lyme disease.     

Enhanced Detection of Host Response Antibodies to Borrelia burgdorferi Using Immuno-PCR

Lyme disease is the fastest-growing zoonotic disease in North America. Current methods for detection of Borrelia burgdorferi infection are challenged by analysis subjectivity and standardization of antigen source. In the present study, we developed an immuno-PCR (iPCR)-based approach employing recombinant in vivo-expressed B. burgdorferi antigens for objective detection of a host immune response to B. burgdorferi infection. iPCR is a liquid-phase protein detection method that combines the sensitivity of PCR with the specificity and versatility of immunoassay-based protocols. Use of magnetic beads coated with intact spirochetes provided effective antigen presentation and allowed detection of host-generated antibodies in experimentally infected mice at day 11 postinoculation, whereas host-generated antibodies were detected at day 14 by enzyme-linked immunosorbent assay (ELISA) and day 21 by immunoblotting. Furthermore, magnetic beads coated with recombinant B. burgdorferi in vivo-expressed antigen OspC or BmpA demonstrated positive detection of host-generated antibodies in mice at day 7 postinoculation with markedly increased iPCR signals above the background, with the quantification cycle (C_q) value for each sample minus the mean background C_q plus 3 standard deviations (ΔC_q) being 4 to 10, whereas ΔC_q was 2.5 for intact spirochete-coated beads. iPCR demonstrated a strong correlation (Spearman rank correlation = 0.895, P < 0.0001) with a commercial ELISA for detection of host antibodies in human Lyme disease patient sera using the B. burgdorferi VlsE C6 peptide. In addition, iPCR showed potential applicability for direct detection of spirochetes in blood. The results presented here indicate that our iPCR assay has the potential to provide an objective format that can be used for sensitive detection of multiple host response antibodies and isotypes to B. burgdorferi infection.     

Species-Specific Plasmid Sequences for PCR Identification of the Three Species of Borrelia burgdorferi Sensu Lato Involved in Lyme Disease

Species-specific sequences were shown to be carried by plasmids of the three main species of Borrelia burgdorferi sensu lato involved in Lyme disease. Libraries of the 16-, 33-, and 25-kb plasmids of B. burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii, respectively, were then built and used to isolate species-specific sequences. After sequencing of the cloned inserts, three sets of primers were designed. They were shown to determine species-specific PCR amplification products. The sensitivities of the PCR assay with these primers were 100 spirochetes for B. burgdorferi sensu stricto and 1,000 spirochetes for B. garinii and B. afzelii. The usefulness of these primers for the identification of species in biological samples (tick, serum, and cerebrospinal fluid samples) was ascertained.     

Inflammation in the Pathogenesis of Lyme Neuroborreliosis

Lyme neuroborreliosis, caused by the spirochete Borrelia burgdorferi, affects both peripheral and central nervous systems. We assessed a causal role for inflammation in Lyme neuroborreliosis pathogenesis by evaluating the induced inflammatory changes in the central nervous system, spinal nerves, and dorsal root ganglia (DRG) of rhesus macaques that were inoculated intrathecally with live B. burgdorferi and either treated with dexamethasone or meloxicam (anti-inflammatory drugs) or left untreated. ELISA of cerebrospinal fluid showed significantly elevated levels of IL-6, IL-8, chemokine ligand 2, and CXCL13 and pleocytosis in all infected animals, except dexamethasone-treated animals. Cerebrospinal fluid and central nervous system tissues of infected animals were culture positive for B. burgdorferi regardless of treatment. B. burgdorferi antigen was detected in the DRG and dorsal roots by immunofluorescence staining and confocal microscopy. Histopathology revealed leptomeningitis, vasculitis, and focal inflammation in the central nervous system; necrotizing focal myelitis in the cervical spinal cord; radiculitis; neuritis and demyelination in the spinal roots; and inflammation with neurodegeneration in the DRG that was concomitant with significant neuronal and satellite glial cell apoptosis. These changes were absent in the dexamethasone-treated animals. Electromyography revealed persistent abnormalities in F-wave chronodispersion in nerve roots of a few infected animals; which were absent in dexamethasone-treated animals. These results suggest that inflammation has a causal role in the pathogenesis of acute Lyme neuroborreliosis.Lyme disease is caused by infection with the spirochete Borrelia burgdorferi (Bb). The spirochetes enter the host''s skin via the bite of infected Ixodes scapularis ticks, causing an inflammatory response that may result in the appearance of a slowly radiating erythematous rash called erythema migrans, followed commonly, after spirochetal dissemination, by early flu-like symptoms, including headaches, fever, fatigue, malaise, and diffuse aches and pains.¹ The disseminating spirochetes show distinct organotropisms, and manifestations of infection can include arthritis, carditis, and neurologic deficits.^2,3Nervous system involvement in Lyme disease, termed Lyme neuroborreliosis (LNB), is manifest in approximately 15% of Lyme disease patients and may affect both the central (CNS) and peripheral nervous systems (PNS). CNS involvement may result in symptoms such as headache, fatigue, memory loss, learning disability, or depression. LNB of the PNS may result in facial nerve palsy, limb pain, sensory loss, and/or muscle weakness.^4–6Clinical findings of patients with LNB typically show the neurologic triad of meningitis, cranial neuritis, and radiculoneuritis,^1,7 commonly described as meningoradiculitis (also known as Garin-Bujadoux-Bannwarth syndrome). Lyme meningitis presents mostly as leptomeningitis, characterized by lymphocytic pleocytosis in the cerebrospinal fluid (CSF).⁸ LNB patients may experience encephalopathy, encephalitis, and encephalomyelitis concomitant with white matter inflammation in the brain and spinal cord.^9–11Neurogenic pain along the back, radiating into the legs and foot, accompanied with weakness, numbness, and tingling in the legs, described as radiculitis or radiculoneuritis, is the most common starting symptom in patients with peripheral LNB.^12,13 Motor deficits are also common, and pain and motor deficits are classically dermatomal or localized to the limb closest to the tick bite, suggesting a pathology that involves sensory neurons that arise from dorsal root ganglia (DRG) in that area of the spinal cord.¹⁴ Other mononeuropathies and plexopathies that result in pain, loss of motor control, and sensory deficits also occur, with patients exhibiting electrophysiologic abnormalities indicative of widespread axonal damage.^12–16 A few case reports also suggest an association with demyelinating neuropathies whereby nerve conduction studies (NCSs) showed conduction slowing and abnormal temporal dispersion, consistent with demyelinating neuropathy.¹⁷Importantly, pathologic examinations of CNS lesions from cases of human LNB have revealed lymphocyte and plasma cell infiltration in the leptomeninges and perivascular infiltrates of immune cells adjacent to white matter lesions in the brain and transverse myelitis lesions in the spinal cord,^18–25 whereas lesions from patients with PNS Lyme disease have shown inflammation in the nerve roots and DRG and patchy multifocal axonal loss accompanied with epineural perivascular inflammatory infiltrates or perineuritis.^12,26,27The rhesus macaque has proved to be an accurate model of human nervous system Lyme disease.^28–31 In one study, almost all of the experimental animals demonstrated perivascular inflammatory infiltrates, multifocal axonal changes, and NCS results that were consistent with mononeuropathy multiplex.³² Sensory ganglia of rhesus macaques that were infected with Bb showed various degrees of necrosis, and peripheral nerve specimens showed multifocal axonal degeneration and regeneration and occasional perivascular inflammatory cellular infiltrates in which macrophages showed positive immunostaining with a monoclonal antibody against a 7.5-kDa lipoprotein of Bb.³² Infection in nerve roots, DRG, and involvement of the spinal cord was also observed in the rhesus monkey model of LNB.^33–35Previously, we reported that rhesus macaques that were inoculated with live Bb into the cisterna magna showed increased levels of IL-6, IL-8, chemokine ligand 2 (CCL2), and CXCL13 in the CSF within 1 week after inoculation, accompanied by a monocytic/lymphocytic pleocytosis.³⁵ In addition, we observed elevated levels of neuronal and satellite glial cell apoptosis in the DRG of infected rhesus macaques, compared with uninfected controls. Importantly, the acute neurologic manifestations observed histopathologically as leptomeningitis and radiculitis were concomitant with the inflammatory response mounted by the Lyme disease spirochete.³⁵ Our aim was to evaluate whether inflammation as induced by the Lyme disease spirochete has a causal role in mediating the pathogenesis of acute LNB. We hypothesized that Bb induces the production of inflammatory mediators in glial and neuronal cells and that this response has a role in potentiating glial and neuronal apoptosis. We addressed this hypothesis by evaluating the inflammatory changes induced in the CNS, spinal nerves, and DRG of rhesus macaques that were inoculated with live Bb into the cisterna magna and were either left untreated or were given the anti-inflammatory drug dexamethasone (Dex), a steroid that inhibits the expression of several immune mediators,³⁶ or meloxicam (Mel), a nonsteroidal anti-inflammatory drug that inhibits cyclooxygenase-2.³⁷ Rhesus macaques were studied for either 8 or 14 weeks. In accordance with our hypothesis we found that the effective suppression of inflammation by Dex treatment resulted in inhibition of glial and neuronal damage, suggesting that inflammation has a causal role in the pathogenesis of LNB. Here, we report the results of these studies.     

Humoral Immunity to Borrelia burgdorferi N40 Decorin Binding Proteins during Infection of Laboratory Mice

A Borrelia burgdorferi N40 genomic expression library was screened with serum from actively infected mice to identify gene products that elicit protective immunity. A clone that contained a putative bicistronic operon containing two genes that encoded 20- and 22-kDa lipoproteins was identified and sequenced. These genes showed homology with the genes encoding decorin binding proteins DbpB and DbpA, respectively, of B. burgdorferi 297 and B31. N40-dbpA DNA hybridized with B. burgdorferi N40 DNA on a single 48-kb linear plasmid. Homologous genes could be amplified under various degrees of stringency by PCR or hybridized by Southern blotting from B. burgdorferi sensu stricto N40 and B31, and from B. burgdorferi sensu lato PBi and 25015, but not PKo. Recombinant N40-DbpB and N40-DbpA were reactive with antibody in serum from infected mice, and serum was more reactive against N40-DbpA than against B. burgdorferi N40 recombinant P39, OspC, or OspA. Sera from mice infected with B. burgdorferi sensu lato strains PKo and PBi were weakly reactive against N40-DbpB and N40-DbpA, and sera from mice infected with 25015 were moderately reactive, compared to sera from mice infected with B. burgdorferi N40. Hyperimmunization of mice with N40-DbpA, but not N40-DbpB, induced protective immunity against syringe challenge with cultured B. burgdorferi N40. DbpA may therefore be one of the antigens responsible for eliciting protective antibody known to exist in serum from infected mice. DNA amplification and serology suggest that DbpB and DbpA are likely to have homologs throughout the B. burgdorferi sensu lato family, but they are likely to be heterogeneous.