RESUMO
Borrelia, spirochetes transmitted by ticks, are the etiological agents of numerous multisystemic diseases, such as Lyme borreliosis (LB) and tick-borne relapsing fever (TBRF). This study focuses on two surface proteins from two Borrelia subspecies involved in these diseases: CspZ, expressed by Borrelia burgdorferi sensu stricto (also named BbCRASP-2 for complement regulator-acquiring surface protein 2), and the factor H binding A (FhbA), expressed by Borrelia hermsii. Numerous subspecies of Borrelia, including these latter, are able to evade the immune defenses of a variety of potential vertebrate hosts in a number of ways. In this context, previous data suggested that both surface proteins play a role in the immune evasion of both Borrelia subspecies by interacting with key regulators of the alternative pathway of the human complement system, factor H (FH) and FH-like protein 1 (FHL-1). The recombinant proteins, CspZ and FhbA, were expressed in Escherichia coli and purified by one-step metal-affinity chromatography, with yields of 15 and 20 mg or pure protein for 1 L of cultured bacteria, respectively. The purity was evaluated by SDS-PAGE and HPLC and is close to about 95%. The mass of CspZ and FhbA was checked by mass spectrometry (MS). Proper folding of CspZ and FhbA was confirmed by circular dichroism (CD), and their biological activity, namely their interaction with purified FH from human serum (recombinant FH15-20 and recombinant FHL-1), was characterized by SPR. Such a study provides the basis for the biochemical characterization of the studied proteins and their biomolecular interactions which is a necessary prerequisite for the development of new approaches to improve the current diagnosis of LB and TBRF. KEY POINTS: ⢠DLS, CD, SEC-MALS, NMR, HPLC, and MS are tools for protein quality assessment ⢠Borrelia spp. possesses immune evasion mechanisms, including human host complement ⢠CspZ and FhbA interact with high affinity (pM to nM) to human FH and rFHL-1.
Assuntos
Proteínas de Bactérias , Proteínas Recombinantes , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Humanos , Borrelia burgdorferi/genética , Borrelia burgdorferi/metabolismo , Borrelia burgdorferi/imunologia , Cromatografia de Afinidade , Escherichia coli/genética , Escherichia coli/metabolismo , Borrelia/genética , Borrelia/metabolismo , Borrelia/imunologia , Fator H do Complemento/metabolismo , Fator H do Complemento/genética , Doença de Lyme/microbiologia , Proteínas Inativadoras do Complemento C3b/genética , Proteínas Inativadoras do Complemento C3b/metabolismo , Expressão GênicaRESUMO
Introduction: Relapsing fever (RF) remains a neglected human disease that is caused by a number of diverse pathogenic Borrelia (B.) species. Characterized by high cell densities in human blood, relapsing fever spirochetes have developed plentiful strategies to avoid recognition by the host defense mechanisms. In this scenario, spirochetal lipoproteins exhibiting multifunctional binding properties in the interaction with host-derived molecules are known to play a key role in adhesion, fibrinolysis and complement activation. Methods: Binding of CihC/FbpC orthologs to different human proteins and conversion of protein-bound plasminogen to proteolytic active plasmin were examined by ELISA. To analyze the inhibitory capacity of CihC/FbpC orthologs on complement activation, a microtiter-based approach was performed. Finally, AlphaFold predictions were utilized to identified the complement-interacting residues. Results and discussion: Here, we elucidate the binding properties of CihC/FbpC-orthologs from distinct RF spirochetes including B. parkeri, B. hermsii, B. turicatae, and B. recurrentis to human fibronectin, plasminogen, and complement component C1r. All CihC/FbpC-orthologs displayed similar binding properties to fibronectin, plasminogen, and C1r, respectively. Functional studies revealed a dose dependent binding of plasminogen to all borrelial proteins and conversion to active plasmin. The proteolytic activity of plasmin was almost completely abrogated by tranexamic acid, indicating that lysine residues are involved in the interaction with this serine protease. In addition, a strong inactivation capacity toward the classical pathway could be demonstrated for the wild-type CihC/FbpC-orthologs as well as for the C-terminal CihC fragment of B. recurrentis. Pre-incubation of human serum with borrelial molecules except CihC/FbpC variants lacking the C-terminal region protected serum-susceptible Borrelia cells from complement-mediated lysis. Utilizing AlphaFold2 predictions and existing crystal structures, we mapped the putative key residues involved in C1r binding on the CihC/FbpC orthologs attempting to explain the relatively small differences in C1r binding affinity despite the substitutions of key residues. Collectively, our data advance the understanding of the multiple binding properties of structural and functional highly similar molecules of relapsing fever spirochetes proposed to be involved in pathogenesis and virulence.
Assuntos
Proteínas de Bactérias , Borrelia , Fibrinólise , Interações Hospedeiro-Patógeno , Plasminogênio , Humanos , Aderência Bacteriana , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Borrelia/imunologia , Borrelia/metabolismo , Ativação do Complemento , Proteínas do Sistema Complemento/imunologia , Proteínas do Sistema Complemento/metabolismo , Fibrinolisina/metabolismo , Fibronectinas/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Evasão da Resposta Imune , Plasminogênio/metabolismo , Ligação Proteica , Febre Recorrente/imunologia , Febre Recorrente/microbiologiaRESUMO
BACKGROUND: Tick- and louse-borne relapsing fever are highly-neglected, vector-borne diseases caused by diverse Borrelia species. Presently, there are no data available on the endemicity of tick- and louse-borne relapsing fever spirochetes in Kenya. Here, we present data of a retrospective study on the seroprevalence of louse-borne relapsing fever (LBRF) in northern Kenya. METHODS: A novel immunoassay, recently established for the diagnosis of LBRF was utilized to screen 2005 blood samples collected from individuals with fever without a source in Turkana County, Kenya between May 2009 and November 2010 for anti-LBRF antibodies. RESULTS: Out of the 2005 sera analyzed, 287 samples (14.3 %) were considered anti-LBRF IgG positive. Subsequent analyses revealed that 87 out of 152 sera randomly selected from these 2005 samples were tested positive (57.2 %) for anti-LBRF IgM antibodies. Most of the IgG and IgM positive samples were from individuals living in northern regions of Turkana County. CONCLUSION: Our serological finding provides strong evidence for the occurrence of LBRF in Kenya.
Assuntos
Anticorpos Antibacterianos , Borrelia , Imunoglobulina G , Imunoglobulina M , Febre Recorrente , Quênia/epidemiologia , Febre Recorrente/epidemiologia , Febre Recorrente/diagnóstico , Febre Recorrente/microbiologia , Febre Recorrente/sangue , Humanos , Estudos Soroepidemiológicos , Estudos Retrospectivos , Masculino , Feminino , Anticorpos Antibacterianos/sangue , Imunoglobulina G/sangue , Borrelia/imunologia , Imunoglobulina M/sangue , Adulto , Animais , Adolescente , Pessoa de Meia-Idade , Adulto Jovem , Criança , Pré-EscolarRESUMO
Interpretation of serological findings in suspected Lyme borreliosis (LB) is challenging and IgM reactivities may have low predictive value. Therefore, if used indiscriminately, there is a risk for incorrect diagnosis of LB. To evaluate the usefulness of IgM titer determination, we performed a study of the prevalence of Borrelia-specific antibodies in serological samples from patients with suspected LB analyzed during the period 2010 - 2021 at the University Hospital of Umeå in Sweden. In total, 19,335 samples had been analyzed for the presence of IgG and IgM antibodies. Overall, there were higher percentages of IgM positive or borderline titers, 1,847 (9.6%) and 905 (4.7%), respectively, than IgG positive or borderline titers, 959 (5.0%) and 406 (2.1%), respectively. Peak number of samples were recorded 2012 - 2013, exceeding 1,800, whereas there were around 1,200 during 2020 - 2021. The peak number of positive IgG and/or positive IgM samples were observed during the period 2015 - 2017 with close to, or above 400, and concomitantly, the proportion of IgG positive samples increased markedly. For IgG positive samples, the increase followed a positive linear time trend (P< 0.001). Peak monthly numbers were observed during August, September, and October. This seasonal increase was significant for the IgG positive group (P< 0.05), but not for the IgM positive/IgG negative group. Repeated samples were obtained from 3,188 individuals and of the initial samples 2,817 were (88%) IgG negative and 2,315 (72%) were IgM negative and of these, 130 (4%) showed IgG seroconversion and 300 (9%) IgM seroconversion. Collectively, the data demonstrate that IgG and/or IgM positive samples represented a minority of all samples, even when repeated sampling had occurred, and IgM positive samples were much more common than IgG positive samples. Thus, the accuracy of the clinical suspicion was low and this will lead to a low predictive value of the analysis, in particular of IgM. These findings question the use of IgM titer determination as a routine analysis.
Assuntos
Anticorpos Antibacterianos , Borrelia , Imunoglobulina G , Imunoglobulina M , Doença de Lyme , Humanos , Anticorpos Antibacterianos/sangue , Borrelia/imunologia , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Doença de Lyme/diagnóstico , Suécia , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Estações do Ano , Testes Diagnósticos de Rotina/normas , Reprodutibilidade dos Testes , Valor Preditivo dos TestesRESUMO
This study aimed to promote the standardization of an indirect, enzyme-linked immunosorbent assay (ELISA) for the serological detection of B. anserina in Gallus gallusdomesticus. An aliquoted sera from vaccinated chicken with B. anserina antigen (GI), experimental infected chickens with B. anserina (GII) and rustic poultry rearing of G. gallus (GIII) were tested with in-house ELISA developed to detect serum antibodies against B. anserina in G. gallus domesticus. On average, the experimentally infected chickens became positive at 9 DPI a mean ± standard deviation (SD) ODI value of 163.11 ± 70.65. The highest observed Optical Density Index (ODI) was 372.54 ± 132.39, at 26 DPI, and the highest overall ODI value was 626.51. The vaccinated chickens became positive between 8 and 10 DPV, with an ODI of 245.59 at 10 DPV, with an overall maximum ODI of 543.13. A total of 108 blood samples were collected from poultry raised on rustic farms. Of the total samples collected, 58.33% (63/108) were considered positive for B. anserina. The maximum ODI found among these rustic chickens was 283.24. This stardardization provided a sensitivity and specificity of 100%.
Este estudo teve como objetivo promover a padronização de um ensaio imunoenzimático indireto (ELISA) para a detecção sorológica de Borrelia anserina em Gallus gallus domesticus. Um frango vacinado com antígeno de B. anserina (GI), frangos infectados experimentalmente com B. anserina (GII) e frangos criados de forma rústica (GIII) foram testados com ELISA indireto in house desenvolvido para a detecção sorológica contra B. anserina em G. gallus domesticus. Em média, os frangos infectados experimentalmente tornaram-se positivos aos 9º dia pós-inoculação (DPI), um valor do índice de densidade óptica (ODI) médio ± desvio padrão (SD) de 163,11 ± 70,65. O maior ODI observado foi 372,54 ± 132,39, em 26ºDPI, e o maior valor geral de ODI foi 626,51. Os frangos vacinados tornaram-se positivos entre 8º e 10° DPV, com um ODI de 245,59 a 10 DPV, com um ODI máximo geral de 543,13. Um total de 108 amostras de sangue foram coletadas de aves criadas em fazendas rústicas. Do total de amostras coletadas, 58,33% (63/108) foram consideradas positivas para B. anserina. O ODI máximo encontrado entre essas galinhas rústicas foi 283,24. Essa padronização proporcionou sensibilidade e especificidade de 100%.
Assuntos
Animais , Doenças das Aves Domésticas/diagnóstico , Borrelia/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Testes Sorológicos/veterinária , Galinhas/imunologia , Anticorpos/análiseRESUMO
For diagnosis of neuroborreliosis, calculation of the antibody index, based on Euroimmun Anti-Borrelia plus VlsE ELISA was compared to Virotech Borrelia Europe plus TpN17 immunoblot-based detection of Borrelia-specific intrathecal antibody production. CXCL13 results in cerebrospinal fluid were used to evaluate discordant results. A total of 64 serum/CSF pairs were analysed. Patients were classified according to European Federation of Neurological Societies criteria incorporating Virotech results. For the Euroimmun assay, a sensitivity of 100% and specificity of 94% was found. Agreement between the both tests was almost perfect (κ 0.81). Both methods are appropriate for the detection of Borrelia-specific intrathecal antibody production.
Assuntos
Anticorpos Antibacterianos/análise , Borrelia/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Immunoblotting/métodos , Neuroborreliose de Lyme/diagnóstico , Adolescente , Adulto , Idoso , Anticorpos Antibacterianos/sangue , Borrelia/isolamento & purificação , Quimiocina CXCL13/análise , Quimiocina CXCL13/imunologia , Feminino , Humanos , Neuroborreliose de Lyme/sangue , Neuroborreliose de Lyme/líquido cefalorraquidiano , Neuroborreliose de Lyme/microbiologia , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
OBJECTIVES: The aim of the study was to analyze some metalloproteinases, cytokines, and chemokines in LB patients and healthy seropositive subjects. The presence of IgM/IgG antibodies against specific Borreliella antigens was analyzed in the presence or absence of clinical manifestations of LB. MATERIAL AND METHODS: The study involved 38 patients diagnosed with LB and arthralgia and/or arthritis symptoms, and 57 foresters presenting no clinical symptoms of LB. The ELISA test was applied for general screening of anti-Borreliella IgM/IgG. Western blot was used for confirmatory diagnosis of LB for the positive and borderline results. Serum IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, TNF, IL-8, CCL5, CXCL9/MIG, CCL2/MCP-1, CXCL10/IP-10 concentrations were measured with the use of the Human Cytometric CBA test. The concentration of MMP-2 and MMP-9 in the serum was determined with the use of ELISA tests. RESULTS: Analysis of the cytokines and chemokines revealed that only the concentration of IL-2 was significantly higher (2.4 pg/m; p=0.00641) in patients with LB symptoms than in the seropositive individuals (0.4 pg/ml). The MMP2 concentration was significantly higher (233.3 ng/ml; p=0.00294) in patients with clinical manifestations of LB than in those occupationally exposed to tick bites, but did not have anti-Borreliella antibodies (192.0 ng/ml). CONCLUSIONS: The presence of IgG antibodies against a number of Borreliella antigens and the differences in the IL-2 and MMP2 levels in seropositive or seronegative individuals and symptomatic LB patients, may indicate differences in the intensity of the immune response to the infection and, consequently, may induce development of clinical manifestations of the disease in seropositive and seronegative individuals.
Assuntos
Doença de Lyme/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Antibacterianos/sangue , Infecções Assintomáticas , Borrelia/imunologia , Borrelia/fisiologia , Quimiocinas/sangue , Citocinas/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Doença de Lyme/diagnóstico , Doença de Lyme/microbiologia , Masculino , Metaloproteinase 2 da Matriz/sangue , Metaloproteinase 9 da Matriz/sangue , Pessoa de Meia-Idade , Picadas de Carrapatos/sangue , Picadas de Carrapatos/diagnóstico , Picadas de Carrapatos/microbiologia , Carrapatos/fisiologia , Adulto JovemRESUMO
BACKGROUND: Various tick-borne infections like borreliosis and rickettsiosis pose a health risk to humans in many parts of the world. We investigated seroprevalence of and seroconversion to Borrelia burgdorferi and Rickettsia spp. and relation to tick-bites, weather and clinical manifestations in Denmark. METHODS: Blood donors were enrolled at the Hospital of Southern Jutland in June-July with follow-up November-February of 2018 and 2019. Blood samples were collected, and a questionnaire regarding tick bites, potential exposures and symptoms was completed at each visit. Samples were tested for presence of IgM and IgG antibodies directed against B. burgdorferi and Rickettsia spp. using R. helvetica and R. felis as antigens. Data were examined for correlation between tick bites, serological results, potential exposures and symptoms. RESULTS: Two-hundred and fourteen (93 follow-ups) and 130 (38 follow-ups) blood donors were included in 2018 and 2019, respectively. The total borrelia seroconversion rate was 6.3% (CI 2.1-10.5), while the prevalence of IgM and IgG antibodies was 7.8% (CI 4.9-10.6) and 6.7% (CI 4-9.3), respectively. Seroconversion to Rickettsia spp. was detected in one participant. Tick bites and seroconversion were not significantly associated with the reported unspecific symptoms, but unspecific symptoms were common in the study population. There was no significant difference in number of tick bites or seroconversion/prevalence between seasons with highly alternating weather. CONCLUSIONS: Results suggest that weather conditions in an individual year have a limited impact. Anti-Borrelia-antibodies do not seem to persist in serum for several years. Rickettsiosis is of limited concern in Denmark.
Assuntos
Picadas de Carrapatos , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/imunologia , Adulto , Idoso , Animais , Borrelia/imunologia , Infecções por Borrelia/imunologia , Borrelia burgdorferi/imunologia , Feminino , Humanos , Imunoglobulina G , Imunoglobulina M , Ixodes/microbiologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prevalência , Rickettsia/imunologia , Infecções por Rickettsia/imunologia , Infecções por Rickettsia/microbiologia , Fatores de Risco , Soroconversão , Estudos Soroepidemiológicos , Inquéritos e Questionários , Adulto JovemRESUMO
The case of a 69-year-old woman with peripheral neuropathy caused by Lyme neuroborreliosis (LNB) in an endemic region in Eastern Austria is reported. The patient had noticed transient numbness of her left leg. On initial examination, she had patchy sensory disturbances of the left lower leg, but ancillary examinations of nerve conduction and cerebrospinal fluid (CSF), including the B-cell chemokine CXCL13, were normal. A re-tap performed 54 days later, following clinical progression with foot drop, widespread lower leg paresthesia, and pain, revealed an increased cell count, autochthonous IgM production, synthesis of Borrelia-specific IgM, and elevated CXCL13. Neurophysiological examinations disclosed an incomplete conduction block, mixed axonal and demyelinating sensorimotor neuropathy, and subacute neurogenic damage of muscles innervated by the peroneal nerve. This case study presents rare evidence of very early diagnostic findings in peripheral neuropathy caused by LNB. These are characterized by insensitivity of CXCL13 in CSF to aid earlier diagnosis and the development of an intrathecal immune response against Borrelia at a later stage. These findings reinforce the need for a re-tap to confirm the diagnosis and facilitate appropriate treatment in this rare manifestation of LNB.
Assuntos
Borrelia/imunologia , Quimiocina CXCL13/líquido cefalorraquidiano , Neuroborreliose de Lyme/complicações , Doenças do Sistema Nervoso Periférico/diagnóstico , Idoso , Áustria , Linfócitos B/imunologia , Biomarcadores/líquido cefalorraquidiano , Feminino , Humanos , Neuroborreliose de Lyme/patologia , Doenças do Sistema Nervoso Periférico/etiologia , Doenças do Sistema Nervoso Periférico/patologiaRESUMO
Borrelia miyamotoi, a member of the tick-borne relapsing fever spirochetes, shows a serum-resistant phenotype in vitro. This ability of B. miyamotoi may contribute to bacterial evasion of the host innate immune system. To investigate the molecular mechanism of serum-resistance, we constructed a membrane protein-encoding gene library of B. miyamotoi using Borrelia garinii strain HT59G, which shows a transformable and serum-susceptible phenotype. By screening the library, we found that bom1093 and bom1515 of B. miyamotoi provided a serum-resistant phenotype to the recipient B. garinii. These B. miyamotoi genes are predicted to encode P35-like antigen genes and are conserved among relapsing fever borreliae. Functional analysis revealed that BOM1093 bound to serum vitronectin and that the C-terminal region of BOM1093 was involved in the vitronectin-binding property. Importantly, the B. garinii transformant was not serum-resistant when the C terminus-truncated BOM1093 was expressed. We also observed that the depletion of vitronectin from human serum enhances the bactericidal activity of BOM1093 expressing B. garinii, and the survival rate of BOM1093 expressing B. garinii in vitronectin-depleted serum is enhanced by the addition of purified vitronectin. Our data suggests that B. miyamotoi utilize BOM1093-mediated binding to vitronectin as a mechanism of serum resistance.
Assuntos
Proteínas de Bactérias/imunologia , Borrelia/imunologia , Febre Recorrente/imunologia , Vitronectina/imunologia , Humanos , Imunidade Inata , Soro/imunologiaRESUMO
Interpretation of serological findings in suspected Lyme borreliosis (LB) may be challenging and IgM reactivities in serum are often unspecific (false positive). There is a risk for overdiagnosis of LB, inadequate use of antibiotics, and potential delay of proper diagnosis. In this study, we evaluated the diagnostic value of IgM analysis in serum and IgM antibody index (AI) in LB diagnosis. This was a retrospective observational study regarding Borrelia-specific antibodies in serum and Borrelia-specific AI in LB investigations being made during 2017 in Jönköping County, Sweden. Medical records of 610 patients with detectable anti-Borrelia antibodies in serum (IgM and/or IgG) and 15 patients with elevated Borrelia-specific AI were retrospectively scrutinized, and the compliance to current European recommendations was assessed. Among the 610 patients, only 30% were tested according to the European recommendations. Within this group of tests taken correctly, 50% of the LB diagnoses in patients with isolated IgM reactivity in serum were retrospectively assessed as incorrect (LB unlikely). Three pediatric patients with clinical and laboratory findings suggestive of Lyme neuroborreliosis (LNB) had elevated IgM AI alone. Serological testing without distinct clinical signs/symptoms consistent with LB contributes to most misdiagnoses. Isolated IgM positivity in serum shows limited clinical value and needs further assessment before being reported by the laboratory. Detection of IgM in combination with IgG antibodies in serum shows no clinical enhancement for correct LB diagnosis compared to isolated IgG positivity. However, Borrelia-specific IgM AI may be important for sensitivity in early LNB.
Assuntos
Anticorpos Antibacterianos/sangue , Borrelia/imunologia , Imunoglobulina M/sangue , Doença de Lyme/sangue , Doença de Lyme/diagnóstico , Borrelia/classificação , Borrelia/genética , Borrelia/isolamento & purificação , Humanos , Imunoglobulina G/sangue , Doença de Lyme/microbiologia , Estudos Retrospectivos , Testes Sorológicos , SuéciaRESUMO
Lyme disease (LD) is the most common tick-borne illness in Europe. Population-based studies in European children are few. This study aimed to assess the incidence, clinical presentation, treatment and outcome of serologically confirmed paediatric LD in the Republic of Ireland over a 5-year period. A retrospective review of records from accredited laboratories performing Borrelia burgdorferi serological testing was undertaken. Proformas were distributed to clinicians of children and adolescents with positive Lyme serology. Data were requested regarding clinical presentation, treatment and outcome. Updated NICE guidelines were used to classify clinical cases. Serology testing for B. burgdorferi was performed on 2908 samples. Sixty-three (2.2%) children were two-tier positive, generating a crude annual incidence rate of 1.15/100,000. Proformas were returned for 55 (87%) and 47 met clinical and laboratory criteria for LD. Twenty-seven (57%) presented with non-focal symptoms (erythema migrans and/or influenza-like symptoms), and 20 (43%) with focal symptoms (cranial nerve involvement, 11; CNS involvement, 8; arthritis, 1). Median age at presentation was 8.2 (2.5-17.9) years. Seventeen (36%) acquired LD overseas. Twenty-five (83%) of the remaining 30 children acquired infection in the West/Northwest of Ireland. Full resolution of symptoms was reported in 97% of those with available data. Serologically confirmed LD in children is relatively rare in the Republic of Ireland. Ninety-eight percent of children tested were seronegative. Of the seropositive cases, 40% could have been diagnosed based on clinical findings alone. Neurological presentations (40%) were common. Full resolution of symptoms occurred in almost all (97%) where data were available.
Assuntos
Antibacterianos/uso terapêutico , Doença de Lyme/epidemiologia , Doença de Lyme/microbiologia , Adolescente , Anticorpos Antibacterianos/sangue , Borrelia/imunologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Irlanda , Doença de Lyme/tratamento farmacológico , Masculino , Estudos RetrospectivosRESUMO
The mammalian host responds to infection with Borrelia spirochetes through a highly orchestrated immune defense involving innate and adaptive effector functions aimed toward limiting pathogen burdens, minimizing tissue injury, and preventing subsequent reinfection. The evolutionary adaptation of Borrelia spirochetes to their reservoir mammalian hosts may allow for its persistence despite this immune defense. This review summarizes our current understanding of the host immune response to B. burgdorferi sensu lato, the most widely studied Borrelia spp. and etiologic agent of Lyme borreliosis. Pertinent literature will be reviewed with emphasis on in vitro, ex vivo and animal studies that influenced our understanding of both the earliest responses to B. burgdorferi as it enters the mammalian host and those that evolve as spirochetes disseminate and establish infection in multiple tissues. Our focus is on the immune response of inbred mice, the most commonly studied animal model of B. burgdorferi infection and surrogate for one of this pathogen's principle natural reservoir hosts, the white-footed deer mouse. Comparison will be made to the immune responses of humans with Lyme borreliosis. Our goal is to provide an understanding of the dynamics of the mammalian immune response during infection with B. burgdorferi and its relation to the outcomes in reservoir (mouse) and non-reservoir (human) hosts.
Assuntos
Infecções por Borrelia/imunologia , Infecções por Borrelia/microbiologia , Borrelia/imunologia , Interações Hospedeiro-Patógeno/imunologia , Animais , Evolução Biológica , Infecções por Borrelia/transmissão , Reservatórios de Doenças , Humanos , Doença de Lyme/imunologia , Doença de Lyme/microbiologia , Doença de Lyme/transmissão , Especificidade de Órgãos/imunologiaRESUMO
Relapsing fever (RF) is claimed a neglected arthropod-borne disease caused by a number of diverse human pathogenic Borrelia (B.) species. These RF borreliae are separated into the groups of tick-transmitted species including B. duttonii, B. hermsii, B. parkeri, B. turicatae, B. hispanica, B. persica, B. caucasica, and B. myiamotoi, and the louse-borne Borrelia species B. recurrentis. As typical blood-borne pathogens achieving high cell concentrations in human blood, RF borreliae (RFB) must outwit innate immunity, in particular complement as the first line of defense. One prominent strategy developed by RFB to evade innate immunity involves inactivation of complement by recruiting distinct complement regulatory proteins, e.g., C1 esterase inhibitor (C1-INH), C4b-binding protein (C4BP), factor H (FH), FH-like protein-1 (FHL-1), and factor H-related proteins FHR-1 and FHR-2, or binding of individual complement components and plasminogen, respectively. A number of multi-functional, complement and plasminogen-binding molecules from distinct Borrelia species have previously been identified and characterized, exhibiting considerable heterogeneity in their sequences, structures, gene localization, and their capacity to bind host-derived proteins. In addition, RFB possess a unique system of antigenic variation, allowing them to change the composition of surface-exposed variable major proteins, thus evading the acquired immune response of the human host. This review focuses on the current knowledge of the immune evasion strategies by RFB and highlights the role of complement-interfering and infection-associated molecules for the pathogenesis of RFB.
Assuntos
Borrelia/imunologia , Evasão da Resposta Imune/imunologia , Febre Recorrente/imunologia , Imunidade Adaptativa , Variação Antigênica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Borrelia/patogenicidade , Proteínas do Sistema Complemento/metabolismo , Humanos , Imunidade Inata , Ligação Proteica , Febre Recorrente/microbiologiaRESUMO
In Lyme disease, the interpretation of diagnostic assays is often misunderstood. Cross-reactions of Borrelia proteins with antigens from other bacterial species are well known. Therefore, to diagnose Lyme disease, the finding of positive IgM antibodies must be accompanied by objectively verified clinical signs and a history of a possible tick exposure. Positive Borrelia IgM antibodies in healthy individuals with nonspecific clinical symptoms are likely a false-positive result for Lyme disease and neither long-term antibiotic treatment nor cycling of different antibiotic regimens is beneficial. To date, there is clear evidence that positive serology does not indicate infection with Borrelia species. Borrelia serology has been reported to be positive for months or years in â¼20% of healthy patients who had experienced Lyme disease in the past. Thus, serology as a single diagnostic tool has a very limited value and should be used only to support clinically suspected cases.
Assuntos
Imunoglobulina G/sangue , Imunoglobulina M/sangue , Doença de Lyme/diagnóstico , Doença de Lyme/imunologia , Anticorpos Antibacterianos/sangue , Borrelia/imunologia , Humanos , Picadas de CarrapatosRESUMO
Lyme disease is the most common vector-borne disease in the northern hemisphere and is caused by spirochetes of the Borrelia burgdorferi sensu lato complex. Lyme borreliae infect diverse vertebrate reservoirs without triggering apparent manifestations in these animals; however, Lyme borreliae strains differ in their reservoir hosts. The mechanisms that drive those differences are unknown. To survive in vertebrate hosts, Lyme borreliae require the ability to escape from host defense mechanisms, in particular complement. To facilitate the evasion of complement, Lyme borreliae produce diverse proteins at different stages of infection, allowing them to persistently survive without being recognized by hosts and potentially resulting in host-specific infection. This review discusses the current knowledge regarding the ecology and evolutionary mechanisms of Lyme borreliae-host associations driven by complement evasion.
Assuntos
Borrelia/imunologia , Interações Hospedeiro-Patógeno/imunologia , Evasão da Resposta Imune/fisiologia , Doença de Lyme/imunologia , Doença de Lyme/microbiologia , Animais , HumanosRESUMO
Homeless people are often exposed to unhygienic environments as well as to animals carrying arthropods which both transmit zoonotic infections and human louse-borne pathogens. We attempted to determine the prevalence of antibodies against several vector-borne and zoonotic pathogens among homeless adults living in Marseille. During the 2005-2015 period, we collected sera samples from 821 homeless adults living in shelters. Antibodies against Bartonella quintana, Bartonella henselae, Borrelia recurrentis, Coxiella burnetii, Francisella tularensis (with a cut-off of 1:100), Rickettsia akari, Rickettsia conorii, Rickettsia felis, Rickettsia prowazekii, and Rickettsia typhi (with a cut-off of 1:64) were searched by microimmunofluorescence (MIF). MIF-positive serum samples were confirmed by cross-adsorption to characterise cross-reacting antigens and immunoblotting. Positive sera by Western blot were further tested using qPCR. We evidenced a prevalence of 4.9% seroreactivity to at least one pathogen including phase II C. burnetii (2.1%), B. quintana (1.7%), R. conorii (0.4%), R. prowazekii (0.4%), R. typhi (0.1%), B. recurrentis (0.1%), and F. tularensis (0.1%). No DNA from any pathogens was detected. A comparison with studies conducted prior to the 2000-2003 period showed a decrease in the overall seroprevalence of several vector-borne and zoonotic infections.
Assuntos
Pessoas Mal Alojadas , Zoonoses/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Antibacterianos/sangue , Borrelia/imunologia , Borrelia/isolamento & purificação , Coxiella burnetii/imunologia , Coxiella burnetii/isolamento & purificação , Estudos Transversais , Vetores de Doenças , Feminino , França/epidemiologia , Humanos , Doença de Lyme/epidemiologia , Doença de Lyme/microbiologia , Masculino , Pessoa de Meia-Idade , Febre Q/epidemiologia , Febre Q/microbiologia , Estudos Soroepidemiológicos , Adulto Jovem , Zoonoses/sangue , Zoonoses/microbiologiaRESUMO
The skin plays a key role in vector-borne diseases because it is the site where the arthropod coinoculates pathogens and its saliva. Lyme borreliosis, particularly well investigated in this context, is a multisystemic infectious disease caused by Borrelia burgdorferi sensu lato and transmitted by the hard tick Ixodes. Numerous in vitro studies were conducted to better understand the role of specific skin cells and tick saliva in host defense, vector feeding, and pathogen transmission. The skin was also evidenced in various animal models as the site of bacterial multiplication and persistence. We present the achievements in this field as well as the gaps that impede comprehensive knowledge of the disease pathophysiology and the development of efficient diagnostic tools and vaccines in humans.
Assuntos
Borrelia/fisiologia , Doença de Lyme/microbiologia , Pele/microbiologia , Animais , Borrelia/imunologia , Humanos , Ixodes/microbiologia , Doença de Lyme/diagnóstico , Doença de Lyme/imunologia , Doença de Lyme/prevenção & controle , Pele/imunologiaRESUMO
The development of vaccines for prevention of diseases caused by pathogenic species can encounter major obstacles if high sequence diversity is observed between individual strains. Therefore, development might be restricted either to conserved antigens, which are often rare, or to multivalent vaccines, which renders the production more costly and cumbersome. In light of this complexity, we applied a structure-based surface shaping approach for the development of a Lyme borreliosis (LB) vaccine suitable for the United States and Europe. The surface of the C-terminal fragment of outer surface protein A (OspA) was divided into distinct regions, based primarily on binding sites of monoclonal antibodies (MAbs). In order to target the six clinically most relevant OspA serotypes (ST) in a single protein, exposed amino acids of the individual regions were exchanged to corresponding amino acids of a chosen OspA serotype. Six chimeric proteins were constructed, and, based on their immunogenicity, four of these chimeras were tested in mouse challenge models. Significant protection could be demonstrated for all four proteins following challenge with infected ticks (OspA ST1, OspA ST2, and OspA ST4) or with in vitro-grown spirochetes (OspA ST1 and OspA ST5). Two of the chimeric proteins were linked to form a fusion protein, which provided significant protection against in vitro-grown spirochetes (OspA ST1) and infected ticks (OspA ST2). This article presents the proof-of-concept study for a multivalent OspA vaccine targeting a wide range of pathogenic LB Borrelia species with a single recombinant antigen for prevention of Lyme borreliosis.
Assuntos
Antígenos de Superfície/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/imunologia , Borrelia/imunologia , Lipoproteínas/imunologia , Doença de Lyme/prevenção & controle , Proteínas Recombinantes/imunologia , Animais , Antígenos de Superfície/administração & dosagem , Antígenos de Superfície/genética , Proteínas da Membrana Bacteriana Externa/administração & dosagem , Proteínas da Membrana Bacteriana Externa/genética , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/genética , Borrelia/genética , Modelos Animais de Doenças , Lipoproteínas/administração & dosagem , Lipoproteínas/genética , Camundongos , Engenharia de Proteínas , Proteínas Recombinantes/genética , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologiaRESUMO
OBJECTIVES: Borrelia miyamotoi is a relapsing fever Borrelia, transmitted by hard (Ixodes) ticks, which are also the main vector for Borrelia burgdorferi. A widely used test for serodiagnosis of Lyme borreliosis is an enzyme immunoassay (EIA) based on the C6 peptide of the B. burgdorferi sl VlsE protein. We set out to study C6 reactivity upon infection with B. miyamotoi in a large well-characterized set of B. miyamotoi disease (BMD) patient sera and in experimental murine infection. METHODS: We performed in silico analyses, comparing the C6-peptide to immunodominant B. miyamotoi variable large proteins (Vlps). Next, we determined C6 reactivity in sera from mice infected with B. miyamotoi and in a unique longitudinal set of 191 sera from 46 BMD patients. RESULTS: In silico analyses revealed similarity of the C6 peptide to domains within B. miyamotoi Vlps. Cross-reactivity against the C6 peptide was confirmed in 21 out of 24 mice experimentally infected with B. miyamotoi. Moreover, 35 out of 46 BMD patients had a C6 EIA Lyme index higher than 1.1 (positive). Interestingly, 27 out of 37 patients with a C6 EIA Lyme index higher than 0.9 (equivocal) were negative when tested for specific B. burgdorferi sl antibodies using a commercially available immunoblot. CONCLUSIONS: We show that infection with B. miyamotoi leads to cross-reactive antibodies to the C6 peptide. Since BMD and Lyme borreliosis are found in the same geographical locations, caution should be used when relying solely on C6 reactivity testing. We propose that a positive C6 EIA with negative immunoblot, especially in patients with fever several weeks after a tick bite, warrants further testing for B. miyamotoi.