Prospects for a vaccine to prevent Lyme disease in humans

A brief history of OspA vaccines including their impact on diagnostic testing for Lyme disease

The only United States Food and Drug Administration approved vaccine preparation to prevent Lyme disease consisted of a single recombinant outer surface protein A (OspA), which was marketed for use from late 1998 until early 2002, with no vaccine currently available for humans for nearly 20 years. OspA vaccines generate an antibody-mediated, transmission blocking immunity, that prevents Borrelia burgdorferi from being transmitted during a tick bite. Although this OspA vaccine was safe and effective, it likely would have required booster doses to maintain immunity, and vaccination regularly caused false positive results on first-tier serologic testing for Lyme disease, when a whole cell-based enzyme immunoassay was used. Clinical trials are in progress to test a new multivalent OspA vaccine designed to prevent Lyme disease in both the United States and Europe.

Testing of the Biocan® B inj. ad us. vet. vaccine and development of the new recombinant vaccine against canine borreliosis

Verification of the efficacy of Biocan B inj. ad us. vet. (Bioveta, a.s.) was done by challenge testing. Ticks collected in the nature were used as natural vectors of the infection. Six beagles and two control ones were used in the test. Formation of outer surface protein A specific antibodies (OspA antibodies) and borrelia specific immonoglobulins (IgG) was measured by Western blot and EIA in the sera samples. The tissue samples were used for detection of borreliae by cultivation method and dark field microscopy (DFM). Formation of IgG antibodies and OspA antibodies after vaccination was observed. The maximum titer level of antibodies was reached between 21. and 49. day after vaccination and then slowly decreased. Presence of borreliae was detected only in skin biopsies of non-vaccinated dogs. The post mortem tissue samples showed presence of borreliae in all of the samples of the non-vaccinated dogs. The tissues of the vaccinated dogs were not infected with borreliae, except for two samples of dog with low titer levels of OspA antibodies. The development of the new vaccine is based on preparation of recombinant outer surface proteins (e.g. rOspA and rOspC) of B. afzelii, B. burgdorferi and B. garinii origin. Chosen recombinant proteins were successfully expressed in E. coli. The obtained purified proteins are currently being tested on laboratory BALB/c mice. Formation of specific antibodies against some recombinant proteins has been confirmed. These proteins are suitable candidates for preparation of a vaccine prototype and they will be subsequently used in challenge tests.

Outer surface lipoproteins ofBorrelia burgdorferi vary in their ability to induce experimental joint injury

OBJECTIVE

To examine the ability of bacterial lipoproteins from the spirochete Borrelia burgdorferi to cause in vivo tissue injury (arthritis).

METHODS

Outer surface proteins (OSPs) from B burgdorferi were used in a rat model of antigen-induced allergic arthritis. Intraarticular challenge with recombinant OspA, OspB, and OspC in nonlipidated (peptide) and lipidated forms was performed in the left knee joint; the contralateral joint received buffer as control. Inflammation was monitored by technetium scintigraphy and histology.

RESULTS

Nonlipidated (peptide) OspA, OspB, and OspC did not induce arthritis; the only exception was polymerized OspA, which was tested in preimmunized rats. Lipidated OspA from 2 different strains and lipidated OspC induced severe arthritis, whereas lipidated OspB failed to induce injury. A synthetic analog of the OSP lipid modification, lipopeptide Pam(3)Cys-Ser-Lys(4)-OH, either alone or coupled to bovine serum albumin, also failed to induce injury. Injury did not develop in control groups that were given the appropriate buffers or lipopolysaccharide. This showed that lipidated borrelial OSPs can be potent arthritogens but vary greatly with respect to their injury-inducing potential. The possession of a lipid modification is essential but is not sufficient to render an OSP arthritogenic.

CONCLUSION

This is the first study to demonstrate that individual lipoproteins from B burgdorferi can induce experimental joint injury in vivo. These results may help elucidate the pathogenesis of Lyme arthritis and, above all, underline the importance of bacterial lipoproteins as major virulence factors.

Active immunisation against human tick-borne diseases

With the development and licensure of a recombinant vaccine for the tick-borne infection Lyme disease, more attention has been paid to other vaccines that have been used or are being developed for the prevention of other tick-borne infections. This review highlights vaccine information for Lyme borreliosis, tick-borne encephalitis (TBE), Rocky Mountain spotted fever, tularaemia, Query (Q) fever, Kyasanur Forest disease (KFD) and tick paralysis. Additionally, discussion on the use of immunisation against the tick itself is included which not only can decrease veterinary tick burdens but may also decrease the transmission of arthropod-transmitted diseases.

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.

Pediatric immunization for the future. Lyme disease vaccine and beyond

This article highlights some of the exciting new developments in pediatric immunization. Starting with the newly licensed Lyme disease vaccine, which is not yet approved for children younger than 15 years of age, the article discusses potential vaccines for severe allergy and cocaine abuse and stresses some of the new techniques in needleless vaccination, including the edible plant technology.

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).

Effects of OspA vaccination on Lyme disease serologic testing

This study presents the effects of OspA vaccination on two-step testing for Borrelia burgdorferi antibodies. Although vaccinees developed enzyme-linked immunosorbent assay reactivity, immunoblots did not fulfill Centers for Disease Control and Prevention criteria for positivity. Furthermore, OspA reactivity did not interfere with interpretation of immunoblots with sera from patients who developed early Lyme disease despite vaccination.

Molecular typing of Borrelia burgdorferi sensu lato: taxonomic, epidemiological, and clinical implications

Borrelia burgdorferi sensu lato, the spirochete that causes human Lyme borreliosis (LB), is a genetically and phenotypically divergent species. In the past several years, various molecular approaches have been developed and used to determine the phenotypic and genetic heterogeneity within the LB-related spirochetes and their potential association with distinct clinical syndromes. These methods include serotyping, multilocus enzyme electrophoresis, DNA-DNA reassociation analysis, rRNA gene restriction analysis (ribotyping), pulsed-field gel electrophoresis, plasmid fingerprinting, randomly amplified polymorphic DNA fingerprinting analysis, species-specific PCR and PCR-based restriction fragment length polymorphism (RFLP) analysis, and sequence analysis of 16S rRNA and other conserved genes. On the basis of DNA-DNA reassociation analysis, 10 different Borrelia species have been described within the B. burgdorferi sensu lato complex: B. burgdorferi sensu stricto, Borrelia garinii, Borrelia afzelii, Borrelia japonica, Borrelia andersonii, Borrelia valaisiana, Borrelia lusitaniae, Borrelia tanukii, Borrelia turdi, and Borrelia bissettii sp. nov. To date, only B. burgdorferi sensu stricto, B. garinii, and B. afzelii are well known to be responsible for causing human disease. Different Borrelia species have been associated with distinct clinical manifestations of LB. In addition, Borrelia species are differentially distributed worldwide and may be maintained through different transmission cycles in nature. In this paper, the molecular methods used for typing of B. burgdorferi sensu lato are reviewed. The current taxonomic status of B. burgdorferi sensu lato and its epidemiological and clinical implications, especiallly correlation between the variable clinical presentations and the infecting Borrelia species, are discussed in detail.

Lyme Disease Vaccine

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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.

Vaccination as a modality to prevent Lyme disease. A status report

Recombinant outer surface protein A (OspA) of Borrelia burgdorferi is a highly protective immunogen for prevention of Lyme disease in experimental animals. Humoral immunity is sufficient for protection. The principal mechanism of action is prevention of transmission of the spirochete from tick to host. A recombinant OspA vaccine has been licensed for use in dogs. The recent licensure of an OspA vaccine for humans resulted from a critical analysis of recently completed efficacy studies.

Lyme borreliosis

Lyme borreliosis (Lyme disease) is often said to be associated with "protean" manifestations, a reference to the ancient god Proteus, who could assume many forms and thus elude his pursuers. This legendary quality has clouded our understanding of Lyme borreliosis by giving Borrelia burgdorferi infection a mythical aura of its own. This review shows that this illness, while incompletely understood, is far more palpable than Proteus and is (in most cases) much more readily subdued. The clinical presentations of Lyme borreliosis do differ in North America and Eurasia, possibly due to the differing pathogenicity of distinct genospecies of Borrelia burgdorferi. The most common manifestation, however, in both continents is erythema migrans. Diagnosis should rest on a careful history and objective clinical findings, supported by appropriately chosen laboratory tests. Reports of coinfection with other tick-borne diseases should prompt a fresh look at Lyme borreliosis. Assertions about "protean manifestations" of B burgdorferi infection should be reappraised. Advances in laboratory techniques are welcome but culture remains the gold standard for the diagnosis--and no laboratory test result should substitute for careful clinical observation and critical analysis.

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.

Efficacy of an OspA vaccine preparation for prevention of Lyme disease in New York State

A multicenter, double-blinded, placebo-controlled study was done comparing a 30-microgram dose of a single protein recombinant OspA vaccine preparation with a saline placebo for efficacy in prevention of Lyme disease in humans. The OspA vaccine (30-microgram dose) or saline placebo was given intramuscularly at day 0, 1 month later, and 12 months later. Cases of possible Lyme disease were evaluated clinically and using culture, polymerase chain reaction and immunoblot assays. Safety data are being analyzed separately. 1,634 adult volunteers were enrolled at a single center in New York State. Vaccine efficacy during the first year was 40% and during the second 37%. Compared with placebo, the OspA vaccine significantly reduced the frequency of Lyme disease during the 2-year study period (P < 0.04, one-tailed Fisher's exact test). Vaccine efficacy was restricted to volunteers under 60 years old (50% vs 9%, P < 0.03, two-tailed Fisher's exact test). A recombinant OspA vaccine preparation was found to have moderate activity in preventing Lyme disease in adults under 60 years old from New York State. Reasons for vaccine failure need to be addressed and a risk benefit ratio calculated.

Epidemiology of European Lyme borreliosis

Lyme borreliosis occurs throughout Europe and is particularly prevalent in the east. In a small proportion of untreated cases serious sequelae may occur, but Lyme borreliosis alone does not cause death. Clinical and serological diagnosis can still be problematic and the various genomospecies may cause different disease manifestations as well as differing immunological responses. However, considerable progress has been made in standardising case definitions and serological testing and interpretation. Few countries have official reporting systems for Lyme borreliosis and most figures on incidence are extrapolated from serodiagnosis data and seroprevalence studies. Geographical variations in incidence seem to correlate with the prevalence of infected ticks, which are mainly associated with varied deciduous forest. The complex ecology of Lyme borreliosis makes it difficult to implement preventive measures, so improving public knowledge of risk factors and methods for personal protection remain the best option at present.

A population genetic study of Borrelia burgdorferi sensu stricto from eastern Long Island, New York, suggested frequency-dependent selection, gene flow and host adaptation

Eastern Long Island, New York, is one of the major foci of Lyme disease in the United States. As in almost all other parts of North America, Lyme disease in this region is caused by a single genomic species of spirochete, Borrelia burgdorferi sensu stricto. For three consecutive years, natural populations of Lyme Borrelia in this region were sampled and studied for gene flow among different locations, changes in population structure over time, and selective forces. The genetic diversity of Borrelia populations was measured at the outer surface protein A (ospA) locus using Cold Single-Stranded Conformation Polymorphism (Cold SSCP) analysis. The Borrelia populations were found to be highly polymorphic within any of thirteen local populations. Ewens-Watterson tests of neutrality revealed that the high level of genetic diversity within local Borrelia populations is maintained by balancing selection. Frequency-dependent selection for the different strains distinguished by the ospA alleles is likely the mechanism of the balancing selection. Allele frequency distributions of Borrelia populations were homogeneous across the region in any particular year, although different infection rates of local tick (Ixodes scapularis) populations suggested that the Borrelia populations were at least partially isolated. Since the allele frequency distribution changed over time, while remaining homogeneous over space, the nearly uniform allele frequency distribution across the region cannot be explained by recent geographic expansion from a single population. This uniform distribution across the region thus may be maintained by selection, or by a significant amount of migration or both. The genetic structure of B. burgdorferi sensu stricto also differed between spirochetes infecting nymphal ticks and those infecting adult ticks. Since larval and nymphal ticks have distinctly different host feeding preferences, host adaptation of spirochete populations is implied. This distinction and an animal study using chipmunks suggest that ticks infected by Borrelia as larvae may have high mortality in the wild. This study represents a genetic analysis of local populations of a bacterial species.

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.

Lyme disease vaccine

Subunit vaccines consisting of single recombinant outer surface proteins (Osp) of Borrelia burgdorferi have been highly successful in protecting mice against challenge by borrelial strains closely related to the strain from which the immunogen was derived. Humoral immunity is sufficient for protection. A dual mode of action for these vaccines has been suggested because serum factors ingested by the tick during the blood meal may begin to reduce the spirochete inoculum prior to transmission to the host. At present two different recombinant OspA vaccine preparations (monovalent) are being evaluated in humans in large-scale phase III efficacy trials in the United States. Local discomfort at the intramuscular injection site has been the principal adverse effect seen to date with these vaccines, but further data on safety are being collected. The greater heterogeneity of OspA among Lyme Borrelia in Europe implies that a vaccine preparation containing multiple antigens (multivalent) may be necessary there, although this is also a concern in the United States.