Lyme borreliosis in rhesus macaques: effects of corticosteroids on spirochetal load and isotype switching of anti-borrelia burgdorferi antibody

Development of Organoids to Study Infectious Host Interactions

Emerging organoid research is paving way for studies in infectious diseases. Described here is a technique for the generation of stem-cell derived organoids for human small intestine and lung together with methods to infect such organoids with a mock pathogen (Cryptosporidium parvum). Such systems are amenable to imaging and processing for molecular biological analyses. It is the intent of this chapter to provide a simple, routine organoid procedure so that in vitro studies with Borrelia such as cell invasion and dissemination can be conducted.

Seroprevalence and Risk Factors of Lyme Borreliosis in The Netherlands: A Population-Based Cross-Sectional Study

Lyme borreliosis (LB) is not notifiable in many European countries, and accurate data on the incidence are often lacking. This study aimed to determine the seroprevalence of Borrelia burgdorferi sensu lato (s.l.)-specific antibodies in the general population of The Netherlands, and to determine risk factors associated with seropositivity. Sera and questionnaires were obtained from participants (n = 5592, aged 0-88 years) enrolled in a nationwide serosurveillance study. The sera were tested for B. burgdorferi s.l.-specific IgM and IgG antibodies using ELISA and immunoblot. Seroprevalence was estimated controlling for the survey design. Risk factors for seropositivity were analyzed using a generalized linear mixed-effect model. In 2016/2017, the seroprevalence in The Netherlands was 4.4% (95% CI 3.5-5.2). Estimates were higher in men (5.7% [95% CI 4.4-7.2]) than in women (3.1% [95% CI 2.0-4.0]), and increased with age from 2.6% (95% CI 1.4-4.4) in children to 7.7% (95% CI 5.9-7.9) in 60- to 88-year-olds. The seroprevalence for B. burgdorferi s.l. in the general population in The Netherlands was comparable to rates reported in European countries. The main risk factors for seropositivity were increasing age, being male and the tick bite frequency. The dynamics of LB infection are complex and involve variables from various disciplines. This could be further elucidated using infectious disease modelling.

Persistent Borrelia burgdorferi Sensu Lato Infection after Antibiotic Treatment: Systematic Overview and Appraisal of the Current Evidence from Experimental Animal Models

Lyme borreliosis is caused by spirochetes belonging to the Borrelia burgdorferi sensu lato group, which are transmitted by Ixodes tick species living in the temperate climate zones of the Northern Hemisphere. The clinical manifestations of Lyme borreliosis are diverse and treated with oral or intravenous antibiotics. In some patients, long-lasting and debilitating symptoms can persist after the recommended antibiotic treatment. The etiology of such persisting symptoms is under debate, and one hypothesis entails persistent infection by a subset of spirochetes after antibiotic therapy. Here, we review and appraise the experimental evidence from in vivo animal studies on the persistence of B. burgdorferi sensu lato infection after antibiotic treatment, focusing on the antimicrobial agents doxycycline and ceftriaxone. Our review indicates that some in vivo animal studies found sporadic positive cultures after antibiotic treatment. However, this culture positivity often seemed to be related to inadequate antibiotic treatment, and the few positive cultures in some studies could not be reproduced in other studies. Overall, current results from animal studies provide insufficient evidence for the persistence of viable and infectious spirochetes after adequate antibiotic treatment. Borrelial nucleic acids, on the contrary, were frequently detected in these animal studies and may thus persist after antibiotic treatment. We put forward that research into the pathogenesis of persisting complaints after antibiotic treatment for Lyme borreliosis in humans should be a top priority, but future studies should most definitely also focus on explanations other than persistent B. burgdorferi sensu lato infection after antibiotic treatment.

Transmission Cycle of Tick-Borne Infections and Co-Infections, Animal Models and Diseases

Tick-borne pathogens such as species of Borrelia, Babesia, Anaplasma, Rickettsia, and Ehrlichia are widespread in the United States and Europe among wildlife, in passerines as well as in domestic and farm animals. Transmission of these pathogens occurs by infected ticks during their blood meal, carnivorism, and through animal bites in wildlife, whereas humans can become infected either by an infected tick bite, through blood transfusion and in some cases, congenitally. The reservoir hosts play an important role in maintaining pathogens in nature and facilitate transmission of individual pathogens or of multiple pathogens simultaneously to humans through ticks. Tick-borne co-infections were first reported in the 1980s in white-footed mice, the most prominent reservoir host for causative organisms in the United States, and they are becoming a major concern for public health now. Various animal infection models have been used extensively to better understand pathogenesis of tick-borne pathogens and to reveal the interaction among pathogens co-existing in the same host. In this review, we focus on the prevalence of these pathogens in different reservoir hosts, animal models used to investigate their pathogenesis and host responses they trigger to understand diseases in humans. We also documented the prevalence of these pathogens as correlating with the infected ticks’ surveillance studies. The association of tick-borne co-infections with other topics such as pathogens virulence factors, host immune responses as they relate to diseases severity, identification of vaccine candidates, and disease economic impact are also briefly addressed here.

Critical analysis of a doxycycline treatment trial of rhesus macaques infected with Borrelia burgdorferi

A critical analysis was conducted of a doxycycline treatment trial of Indian rhesus macaques. In this treatment trial, the investigators attempted to infect the primates with Borrelia burgdorferi sensu stricto by at least 10 tick bites from artificially infected ticks. None of the primates became ill; nevertheless, 5 primates were treated with a 28-day course of oral doxycycline. In contrast to the conclusions of the authors, the data did not convincingly document the existence of viable B. burgdorferi in antibiotic-treated primates. The investigators were unable to cultivate the spirochete from any animal after treatment using highly sensitive in vitro methods. Like many prior animal studies, the current study also did not document that the doxycycline exposure in these animals was similar to that expected in humans. Numerous additional methodologic problems are discussed.

Anti-inflammatory effects of dexamethasone and meloxicam on Borrelia burgdorferi-induced inflammation in neuronal cultures of dorsal root ganglia and myelinating cells of the peripheral nervous system

Background

Lyme neuroborreliosis (LNB), caused by the spirochete Borrelia burgdorferi (Bb), could result in cognitive impairment, motor dysfunction, and radiculoneuritis. We hypothesized that inflammation is a key factor in LNB pathogenesis and recently evaluated the effects of dexamethasone, a steroidal anti-inflammatory drug, and meloxicam a non-steroidal anti-inflammatory drug (NSAID), in a rhesus monkey model of acute LNB. Dexamethasone treatment significantly reduced the levels of immune mediators, and prevented inflammatory and/or neurodegenerative lesions in the central and peripheral nervous systems, and apoptosis in the dorsal root ganglia (DRG). However, infected animals treated with meloxicam showed levels of inflammatory mediators, inflammatory lesions, and DRG cell apoptosis that were similar to that of the infected animals that were left untreated.

Methods

To address the differential anti-inflammatory effects of dexamethasone and meloxicam on neuronal and myelinating cells of the peripheral nervous system (PNS), we evaluated the potential of these drugs to alter the levels of Bb-induced inflammatory mediators in rhesus DRG cell cultures and primary human Schwann cells (HSC), using multiplex enzyme-linked immunosorbent assays (ELISA). We also ascertained the ability of these drugs to modulate cell death as induced by live Bb in HSC using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay and the potential of dexamethasone to modulate Bb-induced apoptosis in HSC by the TUNEL assay.

Results

Earlier, we reported that dexamethasone significantly reduced Bb-induced immune mediators and apoptosis in rhesus DRG cell cultures. Here, we report that dexamethasone but not meloxicam significantly reduces the levels of several cytokines and chemokines as induced by live Bb, in HSC and DRG cell cultures. Further, meloxicam does not significantly alter Bb-induced cell death in HSC, while dexamethasone protects HSC against Bb-induced cell death.

Conclusions

These data help further explain our in vivo findings of significantly reduced levels of inflammatory mediators, DRG-apoptosis, and lack of inflammatory neurodegenerative lesions in the nerve roots and DRG of Bb-infected animals that were treated with dexamethasone, but not meloxicam. Evaluating the role of the signaling mechanisms that contribute to the anti-inflammatory potential of dexamethasone in the context of LNB could serve to identify therapeutic targets for limiting radiculitis and axonal degeneration in peripheral LNB.

Targeting CXCL13 During Neuroinflammation

The chemokine, C-X-C motif ligand 13 (CXCL13), is constitutively expressed in lymphoid organs and controls the recruitment and compartmentalization of lymphocytes and antigen presenting cells within these specialized structures. Recent data, however, also find induction of this molecule during central nervous system (CNS) inflammation under a variety of circumstances. While its role(s) in the pathogenesis of neoplastic, infectious and autoimmune disorders of the CNS remain incompletely understood, several lines of evidence suggest that CXCL13 could become a relevant therapeutic target in at least some of these diseases. This review focuses on how CXCL13 contributes to the pathogenesis of selected CNS disorders involving both experimental animals and humans, paying particular attention to the issue of whether (and if so, how) blockade of this ligand or its receptor might benefit the host. Current blocking strategies largely involve the use of monoclonal antibodies, but an improved understanding of downstream signaling pathways makes small molecule inhibition a future possibility.

Clinical determinants of Lyme borreliosis, babesiosis, bartonellosis, anaplasmosis, and ehrlichiosis in an Australian cohort

Background

Borrelia burgdorferi is the causative agent of Lyme borreliosis. This spirochete, along with Babesia, Bartonella, Anaplasma, Ehrlichia, and the Rickettsia spp. are recognized tick-borne pathogens. In this study, the clinical manifestation of these zoonoses in Australia is described.

Methods

The clinical presentation of 500 patients over the course of 5 years was examined. Evidence of multisystem disease and cranial nerve neuropathy was sought. Supportive laboratory evidence of infection was examined.

Results

Patients from every state of Australia presented with a wide range of symptoms of disease covering multiple systems and a large range of time intervals from onset. Among these patients, 296 (59%) were considered to have a clinical diagnosis of Lyme borreliosis and 273 (54% of the 500) tested positive for the disease, the latter not being a subset of the former. In total, 450 (90%) had either clinical evidence for or laboratory proof of borrelial infection, and the great majority of cases featured neurological symptoms involving the cranial nerves, thus mimicking features of the disease found in Europe and Asia, as distinct from North America (where extracutaneous disease is principally an oligoarticular arthritis). Only 83 patients (17%; number [n]=492) reported never leaving Australia. Of the 500 patients, 317 (63%) had clinical or laboratory-supported evidence of coinfection with Babesia or Bartonella spp. Infection with A. phagocytophilum was detected in three individuals, and Ehrlichia chaffeensis was detected in one individual who had never traveled outside Australia. In the cohort, 30 (11%; n=279) had positive rickettsial serology.

Conclusion

The study suggests that there is a considerable presence of borreliosis in Australia, and a highly significant burden of coinfections accompanying borreliosis transmission. The concept sometimes advanced of a “Lyme-like illness” on the continent needs to be re-examined as the clinical interplay between all these infections. Evidence is presented for the first report of endemic anaplasmosis and ehrlichiosis on the continent.

CXCL13 may improve diagnosis in early neuroborreliosis with atypical laboratory findings

Background

Current guidelines regarding Lyme neuroborreliosis [LNB] require the presence of intrathecal Borrelia burgdorferi-specific antibody production for the definite diagnosis of LNB. However, about 20% of early stage infections present without an elevated antibody index. Moreover, intrathecal B. burgdorferi specific antibody synthesis may persist long after successful therapy of LNB. Recently published data indicate that CXCL13 seems to be a promising diagnostic tool for early stage LNB. In addition, CXCL13 might be suitable for treatment monitoring.

Case presentation

We report on a 39-year-old male patient from southern Germany, who has been suffering from subfebrile body temperatures and meningeal headache for six weeks. On the second day after hospital admission he developed peripheral palsy of the VII. cranial nerve. Cerebrospinal fluid (CSF) analysis showed granulocytic pleocytosis, elevated total protein and blood-CSF barrier dysfunction. Differential diagnostics for granulocytic pleocytosis were unremarkable. Only a second lumbar puncture, on day 6 after admission, revealed a lymphocytic pleocytosis. Serologic testing pointed to clear intrathecal Borrelia specific IgG antibody production. Interestingly, no anti-OspC antibodies were detectable. DNA of the rare Borrelia garinii OspA-type 7 could be amplified from the first CSF sample. The monitoring of CXCL13 in all CSF samples documented a fast decrease from 5000 pg/ml to 450 pg/ml after appropriate antibiotic treatment.

Conclusion

CXCL13 is a novel biomarker with high sensitivity and specificity for acute LNB. Our data show, that CXCL13 might be helpful in unclear cases and support the presumption that it might be a valuable tool for treatment monitoring. Anti-OspC antibody negativity is a rare observation, given the need of OspC for infection of the human hosts. Most likely this is due to a lack of sensitivity of OspC immunoblots that are unable to detect rare OspC variants.

Critical analysis of treatment trials of rhesus macaques infected with Borrelia burgdorferi reveals important flaws in experimental design

A critical analysis of two treatment trials of Chinese rhesus macaques infected with Borrelia burgdorferi indicates that insufficient attention was placed on documenting the blood levels, pharmacokinetics, and pharmacodynamic parameters of the antibiotics used in this host. Consequently, it is impossible to conclude that the findings have validity in judging the efficacy of doxycycline or ceftriaxone for the treatment of Borrelia burgdorferi in this animal model.

Neurologic manifestations of lyme disease

Borrelia burgdorferi infection, the tick-borne spirochetosis known as Lyme disease or Lyme borreliosis, involves the nervous system (neuroborreliosis) in 10% to 15% of patients. Common manifestations include lymphocytic meningitis, cranial neuritis, mononeuropathy multiplex, and painful radiculoneuritis. Rare patients develop inflammation in the brain or spinal cord. Regardless of the form of involvement, neuroborreliosis can be microbiologically cured in virtually all patients using standard 2- to 4-week antimicrobial regimens. Oral regimens appear to be as effective as parenteral ones in most instances. Although patients ill with Lyme disease may have concomitant cognitive or memory difficulty, these symptoms are not specific to neuroborreliosis and, when present in isolation, should not be viewed as suggestive of this diagnosis. When present as part of Lyme disease, they do not require additional or different treatment.

Alterations in cytokines and effects of dexamethasone immunosuppression during subclinical infections of invasive Klebsiella pneumoniae with hypermucoviscosity phenotype in rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques

Invasive Klebsiella pneumoniae with the hypermucoviscosity phenotype (HMV K. pneumoniae) is an emerging human pathogen that also has been attributed to fatal multisystemic disease in African green monkeys at our institution. Combining a cluster of subclinically infected macaques identified in March and April 2008 and the animals documented during a subsequent survey of more than 300 colony nonhuman primates yielded a total of 9 rhesus macaques and 6 cynomolgus macaques that were subclinically infected. In an attempt to propagate the responsible HMV K. pneumoniae strain, a subset of these animals was immunosuppressed with dexamethasone. None of the treated animals developed clinical disease consistent with the multisystemic disease that affected colony African green monkeys. However, cytokine analysis revealed significant alterations of secreted cytokines in macaques subclinically infected with HMV K. pneumoniae when compared with noninfected macaques, thereby calling into question the suitability of animals subclinically infected with HMV K. pneumoniae for use in immunologic or infectious disease research.

Inflammation and central nervous system Lyme disease

Lyme disease, caused by the bacterium Borrelia burgdorferi, can cause multi-systemic signs and symptoms, including peripheral and central nervous system disease. This review examines the evidence for and mechanisms of inflammation in neurologic Lyme disease, with a specific focus on the central nervous system, drawing upon human studies and controlled research with experimentally infected rhesus monkeys. Directions for future human research are suggested that may help to clarify the role of inflammation as a mediator of the chronic persistent symptoms experienced by some patients despite antibiotic treatment for neurologic Lyme disease.

Lyme neuroborreliosis: infection, immunity, and inflammation

Lyme neuroborreliosis (LNB), the neurological manifestation of systemic infection with the complex spirochaete Borrelia burgdorferi, can pose a challenge for practising neurologists. This Review is a summary of clinical presentation, diagnosis, and therapy, as well as of recent advances in our understanding of LNB. Many new insights have been gained through work in experimental models of the disease. An appreciation of the genetic heterogeneity of the causative pathogen has helped clinicians in their understanding of the diverse presentations of LNB.

[Non antibiotic treatments of Lyme borreliosis]

Non-antibiotic treatment of Lyme borreliosis is only indicated in a few specific clinical situations. In chronic Lyme arthritis, intra-articular steroids are useful to immediately relieve symptomatic joint effusion. Nevertheless, 4 studies with weak methodological evidence were convergent enough to recommend not proposing intra-articular injection before or even immediately after antibiotic treatment. The injection can only be recommended in the treatment of patients whose joint effusion persists despite 2 courses of oral antibiotherapy or one course of IV antibiotherapy. For some experts, the injection can only be made after negative PCR assessment of the joint fluid for spirochetes. This recommendation, although logical, has never been evaluated. Radiation synovectomy may be indicated in persistent synovitis after antibiotherapy and before surgical synovectomy. Further studies are mandatory to confirm the role of radiation synovectomy in the local therapy. Arthroscopic synovectomy can reduce the period of joint inflammation when persistent synovitis is associated with significant pain or limited function. Several experts recommend using the procedure only if synovitis persists after 2 months of antibiotherapy and a negative PCR joint fluid assessment. Non-steroidal anti-inflammatory drugs are often prescribed for their symptomatic effects. Experimental data is consensual on the deleterious consequences of systemic corticosteroid therapy. Corticosteroids are not indicated in Lyme's disease. In post Lyme's disease syndrome, patient complaints may lead to a multidisciplinary therapeutic management and the use of neuro-psychiatric drugs.

Molecular characterization of the rhesus rhadinovirus (RRV) ORF4 gene and the RRV complement control protein it encodes

The diversity of viral strategies to modulate complement activation indicates that this component of the immune system has significant antiviral potential. One example is the Kaposi's sarcoma-associated herpesvirus (KSHV) complement control protein (KCP), which inhibits progression of the complement cascade. Rhesus rhadinovirus (RRV), like KSHV, is a member of the subfamily Gammaherpesvirinae and currently provides the only in vivo model of KSHV pathobiology in primates. In the present study, we characterized the KCP homologue encoded by RRV, RRV complement control protein (RCP). Two strains of RRV have been sequenced to date (H26-95 and 17577), and the RCPs they encode differ substantially in structure: RCP from strain H26-95 has four complement control protein (CCP) domains, whereas RCP from strain 17577 has eight CCP domains. Transcriptional analyses of the RCP gene (ORF4, referred to herein as RCP) in infected rhesus macaque fibroblasts mapped the ends of the transcripts of both strains. They revealed that H26-95 encodes a full-length, unspliced RCP transcript, while 17577 RCP generates a full-length unspliced mRNA and two alternatively spliced transcripts. Western blotting confirmed that infected cells express RCP, and immune electron microscopy disclosed this protein on the surface of RRV virions. Functional studies of RCP encoded by both RRV strains revealed their ability to suppress complement activation by the classical (antibody-mediated) pathway. These data provide the foundation for studies into the biological significance of gammaherpesvirus complement regulatory proteins in a tractable, non-human primate model.

Corticosteroid Therapy in an Alphaviral Arthritis

BACKGROUND

: Corticosteroid use during acute viral arthritis is considered to be contraindicated as a result of the risk of immunosuppression causing enhanced infection and disease exacerbation.

OBJECTIVES

: The objective of this study was to analyze the effect of oral corticosteroid therapy on symptoms of the viral arthritic disease, Ross River virus disease (RRVD).

METHODS

: Patients with RRVD were enrolled in 2 prospective longitudinal studies. Medications and comorbidities were recorded and the patients' health was assessed using 2 validated quality-of life-questionnaires, the Comparison of Clinical Health Assessment Questionnaire (CLINHAQ) and the Medical Outcomes Study Short Form (SF-36).

RESULTS

: Six patients taking corticosteroids showed no exacerbation of RRVD compared with patients not taking steroids. The CLINHAQ Functional Disability Index also indicated that corticosteroid users recovered faster compared with patients using nonsteroidal antiinflammatory drugs.

CONCLUSION

: Conventional concern that corticosteroid treatment will exacerbate disease appears unjustified for alphaviral arthritides once serodiagnosis has demonstrated antiviral immunity.

Cardiac involvement in non-human primates infected with the Lyme disease spirochete Borrelia burgdorferi

To investigate cardiac involvement in the non-human primate (NHP) model of Lyme disease, we inoculated 39 adult Macaca mulatta with Borrelia burgdorferi sensu stricto strains N40 (BbN40) by needle (N=22, 14 immunocompetent (IC), seven permanently immunosuppressed (IS), and four transiently immunosuppressed (TISP)) or by tick-bite (N=4, all TISP) or strain 297 (Bb297) by needle (N=2 IS), or with B. garinii strains Pbi (N=4, 2 TISP and 2 IS), 793 (N=2, TISP) or Pli (N=2, TISP). Five uninfected NHPs were used as controls. Infection and inflammation was studied in the hearts and the aorta removed at necropsy 2-32 months after inoculation by (1) H&E and trichrome-staining; (2) immunohistochemistry and digital image analysis; (3) Western blot densitometry; and (4) TaqMan RT-PCR. All NHPs inoculated with BbN40 became infected and showed carditis at necropsy. The predominant cells were T cells, plasma cells, and macrophages. There was increased IgG and IgM in the heart independent of immunosuppression. The B-cell chemokine BLC was significantly increased in IS-NHPs. There was increased deposition of the complement membrane attack complex (MAC) in TISP and IS-NHPs. The spirochetal load was very high in all BbN40-inoculated IS-NHPs but minimal if any in IC or TISP NHPs. Double-immunostaining revealed that many spirochetes in the heart of BbN40-IS NHPs had MAC on their membranes. We conclude that carditis in NHPs infected with B. burgdorferi is frequent and can persist for years but is mild unless they are immunosupressed.

Spinal cord involvement in the nonhuman primate model of Lyme disease

Lyme borreliosis is a multisystemic disease caused by infection with various genospecies of the spirochete Borrelia burgdorferi. The organs most often affected are the skin, joints, the heart, and the central and peripheral nervous systems. Multiple neurological complications can occur, including aseptic meningitis, encephalopathy, facial nerve palsy, radiculitis, myelitis, and peripheral neuropathy. To investigate spinal cord involvement in the nonhuman primate (NHP) model of Lyme borreliosis, we inoculated 25 adult Macaca mulatta with B. burgdorferi sensu strictu strains N40 by needle (N=9) or by tick (N=4) or 297 by needle (N=2), or with B. burgdorferi genospecies garinii strains Pbi (N=4), 793 (N=2), or Pli (N=4) by needle. Immunosuppression either transiently (TISP) or permanently (IS) was used to facilitate establishment of infection. Tissues and fluids were collected at necropsy 7-24 weeks later. Hematoxylin and eosin staining was used to study inflammation, and immunohistochemistry and digital image analysis to measure inflammation and localize spirochetes. The spirochetal load and C1q expression were measured by TaqMan RT-PCR. The results showed meningoradiculitis developed in only one of the 25 NHP's examined, TISP NHP 321 inoculated with B. garinii strain Pbi. Inflammation was localized to nerve roots, dorsal root ganglia, and leptomeninges but rarely to the spinal cord parenchyma itself. T cells and plasma cells were the predominant inflammatory cells. Significantly increased amounts of IgG, IgM, and C1q were found in inflamed spinal cord. Taqman RT-PCR found spirochetes in the spinal cord only in IS-NHP's, mostly in nerve roots and ganglia rather than in the cord parenchyma. C1q mRNA expression was significantly increased in inflamed spinal cord. This is the first comprehensive study of spinal cord involvement in Lyme borreliosis.

Genotype determines phenotype in experimental Lyme borreliosis

Borrelia burgdorferi sensu lato, the causative organism of Lyme borreliosis, is a heterogeneous group of spirochetes, consisting of at least three pathogenic species. To test the hypothesis that the genetic heterogeneity is the reason for the clinical differences, we investigated whether the experimental disease induced by European isolates is different from that induced by American isolates. Two American isolates of species B. burgdorferi sensu stricto were compared with three European isolates, two of species B. garinii, and one of species B. afzelii. The patterns of infection, immunity, and inflammation induced by the different species was distinctive. Inflammatory cells and levels of antibody in B. garinii- and B. afzelii-infected animals were lower than in B. burgdorferi s.s.-infected animals, whereas levels of spirochetal infection in the skin and nervous system were higher in the former group of animals. These data demonstrate that B. burgdorferi s.s. strains are more infective and inflammatory, whereas B. garinii and B. afzelii strains can survive the adaptive immune response to a greater degree and persist at greater numbers in the skin and nervous system. The results explain to a large extent the disparities between LNB in humans in the United States and Europe.

Borrelia burgdorferi transcriptome in the central nervous system of non-human primates

Neurological symptoms are common manifestations of Lyme disease; however, the paucibacillary nature of the spirochete in this environment has precluded a molecular analysis of the spirochete in the CNS. We have now adapted differential expression analysis by using a custom-amplified library (DECAL) in conjunction with Borrelia burgdorferi whole-genome and subgenome arrays to examine in vivo gene expression by B. burgdorferi in a non-human primate (NHP) model of neuroborreliosis. The expression profile of B. burgdorferi was examined in the CNS and heart of steroid-treated and immunocompetent NHPs. Eighty-six chromosomal genes and 80 plasmid-encoded genes were expressed at similar levels in the CNS and heart tissue of both immunocompetent and steroid-treated NHPs. The expression of 66 chromosomal genes and 32 plasmid-encoded genes was increased in the CNS of both immunocompetent and steroid-treated NHPs. It is likely that the expression of these genes is governed by physiological factors specific to the CNS milieu. However, 83 chromosomal and 114 plasmid-encoded genes showed contrasting expression profiles in steroid-treated and immunocompetent NHPs. The effect of dexamethasone on the immune status of the host as well as on the host metabolic pathways could contribute to these differences in the B. burgdorferi transcriptome. Results obtained herein underscore the complex interplay of host factors on B. burgdorferi gene expression in vivo. The results provide a global snapshot of the spirochetal transcriptome in the CNS and should spur the design of experiments aimed at understanding the molecular basis of neuroborreliosis.

Differential detection of B virus and rhesus cytomegalovirus in rhesus macaques

Non-human primate herpesviruses establish and maintain a lifelong persistent infection in immunocompetent hosts in the absence of clinical signs of disease. A fundamental issue for understanding the natural history of non-human primate herpesviruses is whether the viruses are maintained in a truly latent state or one characterized by a low level of chronic expression. To address this issue, a real-time PCR assay was developed to quantify Cercopithecine herpesvirus type 1 (B virus) DNA in mucosal fluids of rhesus macaques. This assay was rapid, sensitive (10 genome copies) and specific for B virus obtained from multiple species of macaques. The shedding profile of B virus was compared to another endemic herpesvirus, rhesus cytomegalovirus (RhCMV), in colony-reared monkeys. Mucosal swabs or saliva samples were taken daily from two groups of seropositive monkeys undergoing either a stressful relocation (group 1) or daily chair restraint (group 2). B virus DNA was detected in mucosal fluids from four animals relocated during the breeding season (group 1) but not from 10 animals moved at other times of the year. No B virus DNA was detected in any group 2 monkey. In contrast, RhCMV DNA was detected in the majority of animals of both groups 1 and 2. Detection of B virus DNA shedding is a relatively rare event associated with the breeding season, while RhCMV DNA is persistently detected in mucosal fluids of most monkeys.

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.