Abilities of OspA proteins from different seroprotective groups of Borrelia burgdorferi to protect hamsters from infection

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.

Vaccination with the ospA- and ospB-Negative Borrelia burgdorferi Strain 50772 Provides Significant Protection against Canine Lyme Disease

Beagles received placebo or ospA- and ospB-negative Borrelia burgdorferi before a tick challenge. A total of 28 (41%) ticks and skin biopsy specimens from each control dog (n = 10) contained B. burgdorferi. In contrast, 12 (19%) ticks recovered from the vaccine recipients (n = 10) were infected (P = 0.0077), and 5 dogs yielded spirochetes from the skin biopsy specimens (P = 0.0325). In addition, 9 (90%) placebo recipients and 4 (40%) vaccine recipients developed joint abnormalities (P = 0.0573). Therefore, vaccination with the ospA- and ospB-negative spirochete provided significant protection against Lyme disease.

Evaluation of OspA vaccination-induced serological correlates of protection against Lyme borreliosis in a mouse model

BACKGROUND

For clinical development of a novel multivalent OspA vaccine against Lyme borreliosis, serological assays are required which can be used to establish immune correlates of protection against infection with Borrelia.

METHODS

Four assays (an OspA IgG ELISA, a competitive inhibition (CI) ELISA, a Borrelia surface-binding (SB) assay and a Borrelia killing assay) were used to evaluate the correlation between immune responses induced by rOspA 1/2 (a chimeric immunogen containing protective epitopes from OspA serotypes 1 and 2), and protective immunity against infection by B. burgdorferi s.s. (OspA-1) and B. afzelii (OspA-2). Mice were immunized with OspA 1/2 doses ranging from 0.3 ng to 100 ng, to induce a range of OspA antibody titers, and exposed to needle challenge with B. burgdorferi s.s. or tick challenge with B. afzelii. Receiver operator characteristics (ROC) curves were constructed for each assay, and the area under the curve (AUC), sensitivity, specificity and Youden Index were calculated. Potential cutoff antibody titers which could be used as correlates of vaccine-induced protection were derived from the maximum Youden Index.

RESULTS

Immunization with OspA-1/2 provided dose-dependent protection against infection with B. burgdorferi s.s. and B. afzelii. Antibody responses detected by all four assays were highly significantly correlated with protection from infection by either B. burgdorferi s.s. (p<0.0001 to 0.0062) or B. afzelii (p<0.0001). ROC analyses of the diagnostic effectiveness of each assay showed the AUC to range between 0.95 and 0.79, demonstrating that all assays distinguish well between infected and non-infected animals. Based on sensitivity, specificity and AUC, the OspA IgG ELISA and SB assays best discriminated between infected and non-infected animals.

CONCLUSIONS

All four assays differentiate well between Borrelia-infected and non-infected animals. The relatively simple, high throughput IgG ELISA would be suitable to establish immune correlates of protection for the novel OspA vaccine in clinical trials.

Hamster and murine models of severe destructive Lyme arthritis

Arthritis is a frequent complication of infection in humans with Borrelia burgdorferi. Weeks to months following the onset of Lyme borreliosis, a histopathological reaction characteristic of synovitis including bone, joint, muscle, or tendon pain may occur. A subpopulation of patients may progress to a chronic, debilitating arthritis months to years after infection which has been classified as severe destructive Lyme arthritis. This arthritis involves focal bone erosion and destruction of articular cartilage. Hamsters and mice are animal models that have been utilized to study articular manifestations of Lyme borreliosis. Infection of immunocompetent LSH hamsters or C3H mice results in a transient synovitis. However, severe destructive Lyme arthritis can be induced by infecting irradiated hamsters or mice and immunocompetent Borrelia-vaccinated hamsters, mice, and interferon-gamma- (IFN-γ-) deficient mice with viable B. burgdorferi. The hamster model of severe destructive Lyme arthritis facilitates easy assessment of Lyme borreliosis vaccine preparations for deleterious effects while murine models of severe destructive Lyme arthritis allow for investigation of mechanisms of immunopathology.

A new approach to a Lyme disease vaccine

A single recombinant outer surface protein A (OspA) antigen designed to contain protective elements from 2 different OspA serotypes (1 and 2) is able to induce antibody responses that protect mice against infection with either Borrelia burgdorferi sensu stricto (OspA serotype-1) or Borrelia afzelii (OspA serotype-2). Protection against infection with B burgdorferi ss strain ZS7 was demonstrated in a needle-challenge model. Protection against B. afzelii species was shown in a tick-challenge model using feral ticks. In both models, as little as .03 μg of antigen, when administered in a 2-dose immunization schedule with aluminum hydroxide as adjuvant, was sufficient to provide complete protection against the species targeted. This proof of principle study proves that knowledge of protective epitopes can be used for the rational design of effective, genetically modified vaccines requiring fewer OspA antigens and suggests that this approach may facilitate the development of an OspA vaccine for global use.

One-year duration of immunity induced by vaccination with a canine Lyme disease bacterin

Laboratory-reared beagles were vaccinated with a placebo or a bacterin comprised of Borrelia burgdorferi S-1-10 and ospA-negative/ospB-negative B. burgdorferi 50772 and challenged after 1 year with B. burgdorferi-infected Ixodes scapularis ticks. For the placebo recipients, spirochetes were recovered from 9 (60%) skin biopsy specimens collected after 1 month, and the organisms persisted in the skin thereafter. Ten (67%) dogs also developed joint infection (3 dogs), lameness or synovitis (7 dogs), or B. burgdorferi-specific antibodies (8 dogs). For the vaccine recipients, spirochetes were recovered from 6 (40%) skin biopsy specimens collected after 1 month. However, subsequent biopsy specimens were negative, and the dogs failed to develop joint infection (P = 0.224), lameness/synovitis (P = 0.006), or Lyme disease-specific antibody responses (P = 0.002). The bacterin provided a high level of protection for 1 year after immunization, and the addition of the OspC-producing B. burgdorferi 50772 provided enhanced protection.

Human Lyme disease vaccines: past and future concerns

The development of a vaccine for Lyme disease was intensely pursued in the 1990s. However, citing a lack of demand, the first human Lyme disease vaccine was withdrawn from the market less than 5 years after its approval. The public's concerns about the vaccine's safety also likely contributed to the withdrawal of the vaccine. Nearly a decade later, no vaccine for human Lyme disease exists. The expansion of Lyme disease's endemic range, as well as the difficulty of diagnosing infection and the disease's steady increase in incidence in the face of proven preventative measures, make the pursuit of a Lyme disease vaccine a worthwhile endeavor. Many believe that the negative public perception of the Lyme disease vaccine will have tarnished any future endeavors towards its development. Importantly, many of the drawbacks of the Lyme disease vaccine were apparent or foreseeable prior to its approval. These pitfalls must be confronted before the construction of a new, effective and safe human Lyme disease vaccine.

Bacterin that induces anti-OspA and anti-OspC borreliacidal antibodies provides a high level of protection against canine Lyme disease

Groups of 15 laboratory-bred beagles were vaccinated and boosted with either a placebo or adjuvanted bivalent bacterin comprised of a traditional Borrelia burgdorferi strain and a unique ospA- and ospB-negative B. burgdorferi strain that expressed high levels of OspC and then challenged with B. burgdorferi-infected Ixodes scapularis ticks. The vaccinated dogs produced high titers of anti-OspA and anti-OspC borreliacidal antibodies, including borreliacidal antibodies specific for an epitope within the last seven amino acids at the OspC carboxy terminus (termed OspC7) that was conserved among pathogenic Borrelia genospecies. In addition, spirochetes were eliminated from the infected ticks that fed on the bacterin recipients, B. burgdorferi was not isolated from the skin or joints, and antibody responses associated specifically with canine infection with B. burgdorferi were not produced. In contrast, B. burgdorferi was recovered from engorged ticks that fed on 13 (87%) placebo-vaccinated dogs (P<0.0001), skin biopsy specimens from 14 (93%) dogs (P<0.0001), and joint tissue specimens from 8 (53%) dogs (P=0.0022). In addition, 14 (93%) dogs developed specific antibody responses against B. burgdorferi proteins, including 11 (73%) with C6 peptide antibodies (P<0.0001). Moreover, 10 (67%) dogs developed Lyme disease-associated joint abnormalities (P<0.0001), including 4 (27%) dogs that developed joint stiffness or lameness and 6 (40%) that developed chronic joint inflammation (synovitis). The results therefore confirmed that the bacterin provided a high level of protection against Lyme disease shortly after immunization.

Interleukin-6 promotes anti-OspA borreliacidal antibody production in vitro

Determination of the immunological mediators responsible for promoting the production of borreliacidal antibody may facilitate the development of an improved borreliosis vaccine for human and veterinary use. Previously, we developed an in vitro assay to determine if borreliacidal antibody production could be augmented by treatment with different cytokines. In this study, in vitro treatment of lymph node cells producing borreliacidal antibody with recombinant interleukin-6 (rIL-6) resulted in a fourfold enhancement of anti-OspA borreliacidal antibody. Moreover, rIL-6 enhanced Western immunoblot titers and increased the number of B lymphocytes. In contrast, treatment of anti-OspA borreliacidal antibody-producing cells with anti-IL-6 resulted in a fourfold reduction in borreliacidal activity. Treatment with anti-IL-6 also inhibited enhanced borreliacidal antibody production induced by anti-gamma interferon. These data suggest that IL-6 plays a significant role in the production of anti-OspA borreliacidal antibodies.

Molecular characterization of the OspA(161-175) T cell epitope associated with treatment-resistant Lyme arthritis: differences among the three pathogenic species of Borrelia burgdorferi sensu lato

Treatment-resistant Lyme arthritis, which may result from infection-induced autoimmunity, is associated with reactivity to a T cell epitope of outer-surface protein A (OspA(161-175)) of Borrelia burgdorferi sensu stricto (Bb). This syndrome has been noted primarily in the United States where only Bb is present, and rarely in Europe where Borrelia garinii (Bg) and Borrelia afzelii (Ba) predominate. To gain a better understanding of this epitope, we identified its species-specific polymorphisms, determined their immunogenicity, and characterized the contribution of individual amino acids. Based on published sequences the Bb peptide differed from the Ba peptide in six of the nine core residues (amino acids 165-173), whereas the Bg peptide usually differed in three of the nine residues. Lymphocytes from seven patients with treatment-resistant Lyme arthritis proliferated in response to the Bb peptide, but not to the Ba or Bg peptide. Substitution analysis showed that valine166 and threonine172 were critical for the immunogenicity of the Bb peptide. Thus, consistent with the geographic distribution of the illness, the European causative agents of Lyme borreliosis usually lack the putative pathogenic OspA epitope. These observations are consistent with the hypothesis that T cell recognition of this epitope is important in the induction of autoimmunity in treatment-resistant Lyme arthritis.

Neutralization of gamma interferon augments borreliacidal antibody production and severe destructive Lyme arthritis in C3H/HeJ mice

Development of a high level of sustained borreliacidal antibody is paramount for maintaining protection against infection with Borrelia burgdorferi. We show that production of borreliacidal antibody can be enhanced by preventing the effects of gamma interferon (IFN-gamma). When lymph node cells capable of producing borreliacidal antibody were cultured with anti-murine IFN-gamma, an eightfold increase in borreliacidal antibody production was obtained. However, anti-IFN-gamma treatment of these cells also enhanced their ability to adaptively induce arthritis. When anti-IFN-gamma-treated lymph node cells producing borreliacidal antibody were infused into C3H/HeJ mice and the mice were then challenged with B. burgdorferi, the mice developed severe destructive Lyme arthritis. Additional studies are needed to delineate the immune response responsible for the induction of arthritis and production of borreliacidal antibody. These studies are needed to ensure an effective and safe vaccine against infection with B. burgdorferi.

Experimental infection of dogs with Borrelia burgdorferi sensu stricto using Ixodes scapularis 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.

Diversity of Ixodes-borne Borrelia species--clinical, pathogenetic, and diagnostic implications and impact on vaccine development

Among Borrelia spirochetes carried by hard ticks belonging to the various Ixodes species, at least 10 species can be distinguished. Of these, Borrelia burgdorferi sensu stricto is involved in human Lyme borreliosis in North America and Europe, and Borrelia garinii and Borrelia afzelii in human disease in Europe and Asia. The pathogenetic significance of the other species is uncertain. Although some of the Borrelia species are restricted to certain tick species, Ixodes ricinus, the vector of Lyme borreliosis in Europe, can be infested by at least five different species, including all three pathogenic species. There is evidence that different Borrelia species are preferentially found in different hosts: In Europe, B. afzelii is frequently found in small mammals, whereas B. garinii and Borrelia valaisiana are often found in birds. This could very well be related to differential sensitivity of these species to complement-mediated bactericidal activity of different hosts. Borrelial complement regulator acquiring proteins, among them OspE or Erp proteins, bind to host factor H and related proteins, and this binding protects against activation of complement by the spirochetal surface. The binding is different for proteins originating from different species and is also depending on the host origin of factor H. In Europe, B. garinii is mainly found in neuroborreliosis, whereas in skin disease B. afzelii is more frequently found. The reason is unclear. The majority of human sera cross-react between proteins of different Borrelia species, but some sera react only with proteins from one of the species. This holds especially for reactivity with OspC. A vaccine against B. burgdorferi sensu stricto has been licensed, but was recently redrawn from the market because of commercial reasons. A vaccine protecting against all three pathogenic species is not yet available.

Interleukin-6 enhances production of anti-OspC immunoglobulin G2b borreliacidal antibody

Protection against infection with Borrelia burgdorferi is dependent primarily on induction of complement-dependent antibody that can kill the spirochete. Measuring the production of sustained high levels of borreliacidal antibody is thus paramount for determining potential vaccine efficacy. We investigated the borreliacidal antibody response in sera and the amount of antibody produced by cultured lymph node cells of C3H/HeJ mice vaccinated with outer surface protein C (OspC). We showed that recombinant OspC was a weak stimulant of borreliacidal antibody production compared to whole cells of OspC-expressing B. burgdorferi. Mice vaccinated with B. burgdorferi in adjuvant produced a high level (titer, 5,120) of anti-OspC borreliacidal antibody, which waned rapidly. Similarly, borreliacidal antibody production by cultured lymph node cells from vaccinated mice peaked soon after vaccination and then decreased. Treatment of lymph node cells with interleukin-6 (IL-6) augmented borreliacidal antibody production, particularly immunoglobulin G2b, whereas treatment with anti-IL-6 inhibited the borreliacidal response. These findings demonstrate a previously unrecognized role for IL-6 in borreliacidal antibody production that may have important implications for vaccine development.

The prevention of Lyme disease with vaccine

Lyme disease is a potentially serious and debilitating infection caused by Borrelia burgdorferi that is endemic in North America, Europe, and Asia. Personal protective and environmental measures have not significantly impacted its increasing incidence. An adjuvanted recombinant vaccine (LYMErix) has been approved in the United States for the prevention of Lyme disease in adults, and has demonstrated both safety and efficacy. A clinical trial of over 10000 adults showed 76% efficacy following the third dose of a 0, 1, 12 schedule. Accelerated schedules demonstrate equivalent levels of protective antibody. Up to 100% of children 2-14 years of age achieve seroprotective levels of antibody. Booster doses induced protective levels of antibody in more than 96% of recipients when administered at months 12 and 24. Only mild or moderate, transient vaccine-associated adverse events have been reported after immunization. The vaccine is a safe and effective method of preventing Lyme disease.

Production of borreliacidal antibody to outer surface protein A in vitro and modulation by interleukin-4

Borreliacidal antibody production is one of several parameters for establishing the effectiveness of Borrelia burgdorferi vaccines. The production of borreliacidal antibody was studied in vitro by culturing immune lymph node cells with macrophages and B. burgdorferi. We showed that borreliacidal antibody, directed primarily against outer surface protein A (OspA), was readily produced by lymph node cells obtained from C3H/HeJ mice vaccinated with formalin-inactivated B. burgdorferi in aluminum hydroxide, but not recombinant OspA. Anti-OspA borreliacidal antibody was detected in supernatants of cultures of lymph node cells obtained on day 7 after vaccination, peaked on day 17, and rapidly declined. The borreliacidal activity was attributable to immunoglobulin G1 (IgG1), IgG2a, and IgG2b antibodies. When lymph node cells were treated with interleukin-4 (IL-4), production of borreliacidal antibody was inhibited but was unaffected by treatment with anti-IL-4 antibodies. These results suggest that other cytokines, but not IL-4, are mainly responsible for production of the secondary borreliacidal antibody response.

Detection of borreliacidal antibodies in dogs after challenge with Borrelia burgdorferi-infected ixodes scapularis ticks

Detection of borreliacidal antibodies is an accurate serodiagnostic test for confirmation of Lyme disease in humans. In this study, 13 pathogen-free beagles, 12 to 26 weeks old, were infected with Borrelia burgdorferi by tick challenge. Dogs were monitored for clinical signs and symptoms of Lyme disease along with borreliacidal antibody production against B. burgdorferi sensu stricto isolates 297 and 50772. Ten (77%) dogs developed lameness in one or more legs within 210 days after attachment of Ixodes scapularis ticks. Eight (80%) of the lame animals had concurrent fever of > or =38 degrees C. Spirochetes were also recovered from the skin and joints of 12 (92%) dogs, but rarely from other organs. Borreliacidal antibodies against B. burgdorferi isolate 297 were detected in only four (31%) dogs, and the levels of killing antibodies remained low for the duration of the infection. In contrast, borreliacidal antibodies against B. burgdorferi isolate 50772 were detected in 13 (100%) dogs within 21 days of infection. Furthermore, the borreliacidal antibody levels correlated with the severity of B. burgdorferi infection. Detection of borreliacidal antibodies, especially against B. burgdorferi isolate 50772, is also a reliable serodiagnostic test for detection of Lyme disease in dogs.

Specific immune response to a synthetic peptide derived from outer surface protein C of Borrelia burgdorferi predicts protective borreliacidal antibodies

In a previous study, we described the development of a new specific serodiagnostic test for Lyme disease involving enzyme-linked immunosorbent assay and a synthetic peptide, OspC-I. The OspC-I peptide is derived from part of the outer surface protein C (OspC) amino acid sequence of Borrelia burgdorferi and is located in the region conserved among B. burgdorferi sensu stricto or sensu lato isolates. In this study, we demonstrate that sera containing antibodies against OspC-I from patients with early Lyme disease had borreliacidal activity against isolates of three genospecies of Lyme disease spirochete, B. burgdoreferi B31, B. garinii HPI and B. afzelii HT61. However, the borreliacidal activity against B. burgdorferi, which has not been isolated in Japan, was weaker than that against the other species. Vaccination of mice with OspC-I induced the production of anti-OspC-I antibodies in serum with borreliacidal activity. The immune mouse serum had significantly higher levels of borreliacidal activity against HP1 and HT61, than against B31. Neutralization of borreliacidal activity with anti-IgM antibodies showed that the borreliacidal activity of anti-OspC-I antibodies in serum was due to IgM. Furthermore. mice vaccinated with OspC-I were protected against challenge with HPI and HT61. but not fully protected against infection with B31. These results suggest that OspC-I is not only a specific antigen for use in serodiagnostic tests for Lyme disease, but is also a potential candidate for a Lyme disease vaccine in Japan.

Protection elicited by native outer membrane protein Oms66 (p66) against host-adapted Borrelia burgdorferi: conformational nature of bactericidal epitopes

Oms66 is a Borrelia burgdorferi outer membrane porin protein whose role in Lyme disease pathogenesis and immunity has not been well established. Oms66 was solubilized from whole-cell lysates of strain B313 (which is derived from B31 but lacks OspA, -B, -C, and -D) and purified to homogeneity by fast-protein liquid chromatography. Purified native Oms66 (nOms66), which retained the ability to form large channels in a planar lipid bilayer model membrane system, and denatured Oms66 (hOms66) were used to immunize New Zealand White rabbits. The resulting Oms66 antisera were tested in a complement-dependent borreliacidal assay in parallel with basal serum and with serum from rabbits immune to reinfection with B. burgdorferi (IRS). IRS showed high-titer complement-dependent killing of both strains B31 and B313. Sera from animals immunized with nOms66 showed high-titer complement-dependent killing activity against strain B313 but exhibited no killing of B31. By comparison, serum generated from immunizations with hOms66 showed no killing activity against either strain. Following adsorption of antiserum to nOms66 with recombinant Oms66 (rOms66), the serum antibodies no longer bound to rOms66 or to nOms66 that had been denatured with 8 M urea. However, the antibodies still bound to nOms66 and killing activity against B313 was retained, thus suggesting that native, conformational epitopes are targets of this bactericidal activity. Six C3H HeJ mice were immunized with nOms66 and were challenged using "host-adapted" B. burgdorferi B31 by skin implantation of infected mouse ear tissue. Four of the six mice were protected against both localized and disseminated infection. These findings indicate that native Oms66 can elicit potent bactericidal activity and significant protective immunity against host-adapted organisms.

The Lyme disease vaccine: conception, development, and implementation

In the past 20 years, remarkable strides have been made toward understanding and preventing Lyme disease in humans. In December 1998, the U.S. Food and Drug Administration approved a recombinant outer surface protein A vaccine against Lyme disease (LYMErix, SmithKline Beecham, Philadelphia, Pennsylvania). The vaccine, which is derived from a lipidated outer surface protein of the causative spirochete Borrelia burgdorferi, is important because it may decrease the morbidity and financial costs associated with Lyme disease. Its mechanism is unique because it works inside the tick vector itself, preventing the human from becoming infected.

Occurrence of severe destructive lyme arthritis in hamsters vaccinated with outer surface protein A and challenged with Borrelia burgdorferi

Arthritis is a frequent and major complication of infection with Borrelia burgdorferi sensu stricto. The antigens responsible for the induction of arthritis are unknown. Here we provide direct evidence that a major surface protein, outer surface protein A (OspA), can induce arthritis. Hamsters were vaccinated with 30, 60, or 120 microg of recombinant OspA (rOspA) in aluminum hydroxide and challenged with B. burgdorferi sensu stricto isolate 297 or C-1-11. Swelling of the hind paws was detected in 100, 100, and 50% of hamsters vaccinated with 30, 60, or 120 microg of rOspA, respectively. In addition, arthritis developed in 57% of hamsters vaccinated with a canine rOspA vaccine after infection with B. burgdorferi sensu stricto. When the canine rOspA vaccine was combined with aluminum hydroxide, all vaccinated hamsters developed arthritis after challenge with B. burgdorferi sensu stricto. Histopathologic examination confirmed the development of severe destructive arthritis in rOspA-vaccinated hamsters challenged with B. burgdorferi sensu stricto. These findings suggest that rOspA vaccines should be modified to eliminate epitopes of OspA responsible for the induction of arthritis. Our results are important because an rOspA vaccine in aluminum hydroxide was approved by the Food and Drug Administration for use in humans.

Adjuvanted Lyme disease vaccine: a review of its use in the management of Lyme disease

Lyme disease is a potentially serious infection which is caused by the spirochaete Borrelia burgdorferi and is endemic in certain areas of North America, Europe and Asia. Lyme disease vaccine (LYMErix) is an adjuvanted formulation of the outer surface protein A (OspA) of the causative spirochaete. It acts by inducing high titres of anti-OspA antibodies (anti-OspA), which must be present in vaccinated individuals before exposure to B. burgdorferi to provide protection against Lyme disease. Lyme disease vaccine efficacy against Lyme disease was 80% for definite and asymptomatic cases and 76% for definite cases at year 2 using the recommended dosage regimen [30 microg at months 0, 1 and 12 (0, 1, 12 schedule)] in a randomised, double-blind, multicentre trial in 10,936 enrolled adult volunteers who resided in areas of the US endemic for Lyme disease. On the basis of an anti-OspA correlate of protection, Lyme disease vaccine 30 microg was equally effective when administered by a shorter schedule (0, 1, 6 schedule); > or = 90% of adult volunteers developed protective anti-OspA titres with this or the 0, 1, 12 schedule. Although published data are fewer, a 0, 1, 2 schedule has also shown promise in adults. In addition, virtually all children (aged 2 to 15 years) given Lyme disease vaccine 30 microg developed protective anti-OspA titres, but published data are also limited and results of a large paediatric trial are awaited with interest. Long term protection against Lyme disease appears to be possible with Lyme disease vaccine. Although anti-OspA titres decline rapidly after completion of the recommended schedule, booster doses of 30 microg of the vaccine induced protective anti-OspA titres in > or = 96% of adult volunteers when administered 12 and/or 24 months later. Lyme disease vaccine 30 microg is well tolerated: most vaccination-related adverse events were transient and mild or moderate in severity in clinical trials. The most common spontaneously reported adverse event was pain at the injection site in 24% of vaccine recipients (vs 7.6% of the placebo group). The incidence of spontaneously reported, early nonspecific systemic adverse events was <4% but was higher with the vaccine than with placebo for some events (e.g. myalgias, fever and chills but not arthralgia). There appeared to be no association between the vaccine and the incidence of arthritis or any late systemic adverse events. The tolerability profile of Lyme disease vaccine did not appear to vary with the schedule of administration, nor to differ between adults and children.

CONCLUSIONS

Lyme disease vaccine, an adjuvanted formulation of OspA, protects most adults against Lyme disease when administered by the recommended 0, 1, 12 schedule before disease exposure, and is well tolerated. The optimal schedule(s) of administration, duration of protection against Lyme disease, long term tolerability in adults and potential role in children are not fully defined for this vaccine. Lyme disease vaccine is indicated in North America for active immunisation of adults at moderate to high risk of contracting Lyme disease.

Comprehensive detection of immunorelevant Borrelia garinii antigens by two-dimensional electrophoresis

Lyme disease is caused by spirochetes of the Borrelia burgdofferi complex and has been reported in many temperate parts of the Northern Hemisphere. The B. burgdorferi complex consists of at least five different species and five genotypes with different pathogenicity. Serodiagnosis was achieved by detection of antigens on one-dimensional (1-D) immunoblots. A systematic and comprehensive approach to elucidate antigens has been started here by the combination of two-dimensional electrophoresis (2-DE) immunoblotting with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Antigens in the proteome of B. garinii BITS were analyzed for their reactivity with sera from patients in early stage (erythema migrans) and late manifestations (neuroborreliosis late, arthritis and acrodermatitis chronica athrophicans) of borreliosis. A strategy to handle the enormous amount of data was developed and 65 antigens were detected, of which 20 were identified. These comprise the known antigens from 1-D immunoblots used routinely in serodiagnosis and additionally the two new antigens, GAPDH and the ABC transporter oligopeptide permease. Several disease-stage unique proteins were detected and some of them identified. The genetic variability between B. garinii strains BITS and 20047, B. afzelii, and B. burgdofferi, sensu stricto, seen on the 2-DE patterns underlines the necessity of the search for additional antigens to improve the serodiagnosis and development of vaccines to be used outside of Northern America. A 2-DE database of B. garinii was built up and is available on the World Wide Web (http://www.mpiib-berlin.mpg.de/2D-PAGE).

Lyme disease prevention and vaccine prophylaxis

OBJECTIVE

To provide a comprehensive review of the epidemiology, diagnosis, and prevention of Lyme disease with a focus on the Lyme disease vaccine.

DATA SOURCE

A computerized search of MEDLINE (January 1996-December 1998) was used to identify articles regarding Lyme disease, Borrelia burgdorferi, epidemiology, prevention, and vaccine.

DATA SYNTHESIS

Lyme disease is a condition caused by infection with B. burgdorferi. The organism is carried by certain species of Ixodes ticks and is the most common tick-borne disease in the US. In patients with clinical manifestations of Lyme disease, various pharmacotherapeutic approaches have proven effective in treatment of the clinical features. Prevention strategies exist; however, their application is sometimes difficult. A vaccine for the prevention of Lyme disease is available, and another is being considered for approval. The recombinant outer surface protein A (OspA) vaccines to prevent Lyme disease are immunogenic and have an acceptable adverse effect profile. These vaccines are highly efficacious for the prevention of Lyme disease.

CONCLUSIONS

Lyme disease is the most common tick-borne disease in the US. The infection, caused by B. burgdorferi, results in dermatologic, neurologic, cardiovascular, and musculoskeletal manifestations. Until recently, tick bite prevention strategies were the only means of decreasing the risk of acquiring the infection. The OspA vaccines are efficacious for the prevention of infection. Although universal immunization with these vaccines is unlikely, the availability of effective vaccines represents an important tool for the prevention of Lyme disease in endemic regions of the US.

Safety and immunogenicity of recombinant Bacille Calmette-Guérin (rBCG) expressing Borrelia burgdorferi outer surface protein A (OspA) lipoprotein in adult volunteers: a candidate Lyme disease vaccine

This phase I clinical trial was designed to determine the feasibility of using rBCG as a live bacterial vaccine vector for the outer surface protein A (OspA) of Borrelia burgdorferi and as model for other vaccines based on a rBCG vector. To construct the vaccine, a signal peptide derived from a mycobacterial lipoprotein was used to direct the export, and membrane-associated surface expression, of OspA in a standard strain of BCG (Connaught). The rBCG OspA vaccine was safe and immunogenic in several animal species, and protective in a mouse model of Lyme borreliosis. An intradermal injection (0.1 ml) of rBCG OspA was administered to 24 healthy adult volunteers sequentially at one of four dose levels, ranging from 2.0 x 10(4) CFU to 2 x 10(7) CFU, using a dose-escalation design. All volunteers were initially PPD-skin test and OspA antibody negative, and they were monitored for 2 years after immunization. Three volunteers had mild flu-like reactions 1-2 days after vaccination. Local ulceration and drainage at the site of injection, which occurred in 50% and 83% of volunteers in the two highest dose groups, persisted for 1-70 days before the ulcers healed. Most of the drainage samples yielded rBCG colonies that contained the OspA plasmid. Thirteen of 24 vaccinees, principally in the two highest dose groups, converted their PPD skin tests from negative to positive. None of the 24 volunteers developed OspA antibody. In conclusion, the current rBCG vaccine construct, the first such construct tested in humans, had a safety profile comparable to that of licensed BCG, but it did not elicit primary humoral responses to the vectored antigen.

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.

A vaccine consisting of recombinant Borrelia burgdorferi outer-surface protein A to prevent Lyme disease. Recombinant Outer-Surface Protein A Lyme Disease Vaccine Study Consortium

BACKGROUND

Lyme disease is a multisystem inflammatory disease caused by infection with the tick-borne spirochete Borrelia burgdorferi and is the most common vector-borne infection in the United States. We assessed the efficacy of a recombinant vaccine consisting of outer-surface protein A (OspA) without adjuvant in subjects at risk for Lyme disease.

METHODS

For this double-blind trial, 10,305 subjects 18 years of age or older were recruited at 14 sites in areas of the United States where Lyme disease was endemic; the subjects were randomly assigned to receive either placebo (5149 subjects) or 30 microg of OspA vaccine (5156 subjects). The first two injections were administered 1 month apart, and 7515 subjects also received a booster dose at 12 months. The subjects were observed for two seasons during which the risk of transmission of Lyme disease was high. The primary end point was the number of new clinically and serologically confirmed cases of Lyme disease.

RESULTS

The efficacy of the vaccine was 68 percent in the first year of the study in the entire population and 92 percent in the second year among the 3745 subjects who received the third injection. The vaccine was well tolerated. There was a higher incidence of mild, self-limited local and systemic reactions in the vaccine group, but only during the seven days after vaccination. There was no significant increase in the frequency of arthritis or neurologic events in vaccine recipients.

CONCLUSIONS

In this study, OspA vaccine was safe and effective in the prevention of Lyme disease.

Vaccination against Lyme disease with recombinant Borrelia burgdorferi outer-surface lipoprotein A with adjuvant. Lyme Disease Vaccine Study Group

BACKGROUND

The risk of acquiring Lyme disease is high in areas in which the disease is endemic, and the development of a safe and effective vaccine is therefore important.

METHODS

We conducted a multicenter, double-blind, randomized trial involving 10,936 subjects who lived in areas of the United States in which Lyme disease is endemic. Participants received an injection of either recombinant Borrelia burgdorferi outer-surface lipoprotein A (OspA) with adjuvant or placebo at enrollment and 1 and 12 months later. In cases of suspected Lyme disease, culture of skin lesions, polymerase-chain-reaction testing, or serologic testing was done. Serologic testing was performed 12 and 20 months after study entry to detect asymptomatic infections.

RESULTS

In the first year, after two injections, 22 subjects in the vaccine group and 43 in the placebo group contracted definite Lyme disease (P=0.009); vaccine efficacy was 49 percent (95 percent confidence interval, 15 to 69 percent). In the second year, after the third injection, 16 vaccine recipients and 66 placebo recipients contracted definite Lyme disease (P<0.001); vaccine efficacy was 76 percent (95 percent confidence interval, 58 to 86 percent). The efficacy of the vaccine in preventing asymptomatic infection was 83 percent in the first year and 100 percent in the second year. Injection of the vaccine was associated with mild-to-moderate local or systemic reactions lasting a median of three days.

CONCLUSIONS

Three injections of vaccine prevented most definite cases of Lyme disease or asymptomatic B. burgdorferi infection.

Inhibition of the production of anti-OspA borreliacidal antibody with T cells from hamsters vaccinated against Borrelia burgdorferi

The serious morbidity associated with Lyme borreliosis has focused considerable effort on the development of a comprehensive vaccine for protection against infection with Borrelia burgdorferi. Induction of borreliacidal antibody by vaccination or infection has been shown to correlate with protection of humans and animals against infection with the Lyme spirochete. In this report, we showed that high levels of borreliacidal antibody (titer of 1,280) were produced in vitro when T and B cells from hamsters 14 days after vaccination were incubated with macrophages and B. burgdorferi. By contrast, T and B cells from hamsters 7 or 21 days after vaccination failed to initiate production of borreliacidal activity. Furthermore, the T cells from hamsters 7 or 21 days after vaccination inhibited the in vitro production of borreliacidal antibody when cocultured with T and B cells obtained from hamsters 14 days after vaccination. When cell-free supernatants from the suspensions of T and B cells from hamsters 14 days after vaccination were absorbed with recombinant OspA, they lost nearly all borreliacidal activity. The removal of anti-OspA antibody resulted in a decrease in borreliacidal titer from 1,280 to less than 4. These results demonstrate that T cells from vaccinated animals can prevent a sustained production of protective borreliacidal antibody.

Experimental infection of cattle with several Borrelia burgdorferi sensu lato strains; immunological heterogeneity of strains as revealed in serological tests

Twenty-three experimental cattle, mainly calves, were each inoculated 1-3 times with one of ten Finnish Borrelia burgdorferi sensu lato strains. All three genospecies were represented. Borreliae were administered mainly by both intravenous (about 10(6) to 10(9) spirochaetes) and intradermal (10(4)) routes, and on six occasions subcutaneously (10(3)) only. For infectivity control and comparison purposes mice and rabbits were inoculated simultaneously. Immune responses in cattle were monitored both with whole-cell sonicate enzyme-linked immunosorbent assay (IgG-ELISA) and indirect immunofluorescent assay (IgM-IgG-IFA). Five Finnish strains and the American strain B31 were used as antigens. No clinical signs of borreliosis were observed. Of the strains, 7/10 were interpreted by the immune responses to have caused relatively short-term subclinical infections of varying intensity. Borreliae could not be isolated from blood or other organ specimens of cattle. A rough estimate of the mean infectious dose in the conditions of experiments is 10(6) to 10(7) organisms. In conclusion, the overall result appears to argue a low susceptibility of cattle to clinical borreliosis, at least when infected by Finnish strains of the agent. Significant antigen-specific differences were observed both by ELISA and IFA in detection and quantification of immune responses. As a rule, the homologous antigen was found to be the most sensitive. Genospecies differences were mostly distinct. Antigens of two Borrelia garinii isolates proved practically equal in sensitivity, whereas major differences were displayed between two Borrelia afzelii antigens. In an IFA study, an American (B31) and a Finnish B. burgdorferi sensu stricto strain proved equally sensitive as antigens. In two relatively strong primary immune responses the antigen-specific measurement differences were such that diagnostically in a cross-sectional study only the homologous antigen or an antigen of the same genospecies would have been sufficiently sensitive to show a positive result.

Lyme disease: a review of aspects of its immunology and immunopathogenesis

Lyme disease, caused by Borrelia burgdorferi, causes a multisystem inflammatory ailment, although the precise means of tissue damage are not well understood. It is clear that the organism is present at the site of inflammation in many organs and that many of the features of the illness are relieved by antibiotic therapy. A complex interaction between spirochete and immune systems of a number of mammalian hosts, in human disease and animal models, has been described. It is clear that T cells and macrophages are intimately associated with the pathogenesis of arthritis and that immune mechanisms are involved in other aspects of disease. Inflammation directed at persistence of Borrelial antigens is a plausible explanation for persisting arthritis. Autoimmunity based on molecular mimicry may play a role in the pathogenesis of Lyme disease. Humoral immunity plays a protective role, prompting interest in vaccine development. Significant variation in certain of the outer surface proteins suggests that multiple proteins, peptides, or chimeric vaccines may be needed to provide a sufficiently broad humoral protective response.

Reinfection in Lyme borreliosis

Two patients with reinfection of Borrelia burgdorferi are presented. An 11-year-old girl developed recurrent acute peripheral facial palsy at an interval of five years. A 64-year-old woman showed paraesthesia in the leg and effusion in the knee. Three years later, an erythema migrans developed at the thigh. In both patients tick bites, corresponding clinical manifestations, and detection of specific antibodies proved the reinfections. The course of the humoral immune responses showed basic differences between the patients. At the interval between the first and second infection, the specific antibodies of the girl decreased beyond the cut-off level. On the other hand, the titer of specific IgG antibodies of the other patient remained at a constant level. Reasons for the failure of immune protection are discussed.

Immunity to Lyme disease: protection, pathology and persistence

Persistence of the Lyme disease spirochete, Borrelia burgdorferi, in the presence of an active immune response has been well documented. Evidence from the past year indicates that modulation of surface antigens by the spirochete may be a major mechanism for evading the immune response.

Outer surface protein C (OspC), but not P39, is a protective immunogen against a tick-transmitted Borrelia burgdorferi challenge: evidence for a conformational protective epitope in OspC

Outbred mice were immunized with the soluble fraction of a crude Escherichia coli lysate containing either recombinant outer surface protein C (OspC or P39 of Borrelia burgdorferi B31 (low passage). Following seroconversion, the mice were challenged with an infectious dose of B. burgdorferi B31 via the natural transmission mode of tick bite. Three mice immunized with P39 were not protected; however, all 12 of the recombinant OspC-immunized mice were protected from infection as assayed by culture and serology. Although OspC has been shown to be a protective immunogen against challenge with in vitro-cultured borrelia administered by needle, this study is the first to demonstrate OspC effectiveness against tick-borne spirochetes. Following feeding, all ticks still harbored B. burgdorferi, suggesting that the mechanism of protection is not linked to destruction of the infectious spirochete within the tick. In a separate experiment, groups of four mice were immunized with protein fractions from B. burgdorferi B31 purified by preparative gel electrophoresis in an attempt to identify potential protective antigens. Many of these mice developed high-titer-antibody responses against OspC, but curiously the mice were susceptible to B. burgdorferi infection via tick bite. These results suggest that the protective epitope(s) on OspC is heat sensitive/conformational, a finding which has implications in vaccine development.

Immunological and molecular variability of OspA and OspC. Implications for Borrelia vaccine development

Borrelia burgdorferi sensu lato, the etiological agent of Lyme borreliosis is considerably heterogeneous in Europe. Since the outer surface proteins OspA and OspC are the most promising candidates for a Borrelia vaccine the immunological heterogeneity of these proteins was investigated. By immunological analysis with monoclonal antibodies and sequence analysis of PCR amplified OspA and OspC at least seven and 16 different types, respectively, were found. Whereas skin isolates (n = 68) were quite homogeneous (84% belonged to OspA-serotype 2 or Borrelia afzelii), isolates from human cerebrospinal fluid and from ticks (n = 43 and n = 90 respectively) were highly heterogeneous in their OspA-serotypes with prevalence of the Borrelia garinii associated types (about 70%). OspA-type 4 was often found among isolates from cerebrospinal fluid (28%). In ticks type 4 OspA has not been detected by culture so far. However, as reported in a previous study, type 4 OspA could be detected in ticks by the highly sensitive PCR technique.

Experimental immunization against Lyme borreliosis with recombinant Osp proteins: an overview

Interest in human and veterinary vaccines against Lyme borreliosis is growing. Both whole cell immunization and subunit vaccines can protect against infection with Borrelia burgdorferi. For development of a human vaccine the focus has been on a subunit vaccine. The most promising candidate is OspA, a major outer membrane lipoprotein of B. burgdorferi sensu lato. Of Osp proteins A through D, OspA shows the least variability between strains in its sequence and in the level of its expression. Borreliae in ticks express OspA. Antibodies to OspA kill borreliae in vitro and provide passive protection in mice. Active immunization of mice with OspA provides protection against challenge by syringe inoculation or tick bite. The lipid moiety of the OspA is necessary for immunogenicity in the absence of a potent adjuvant. A recombinant OspA-based vaccine is already in clinical trials. Although there is compelling evidence that immunization with OspA will provide protection, questions remain regarding the duration of protection from such immunization, the necessity to have a minimum level of neutralizing antibodies at all times for protection, and the relationship of an immune response to OspA and autoimmune features of Lyme borreliosis. The experimental aspects of immunization with Osp-A based constructs and other Lyme vaccine candidates are reviewed and discussed.