Immunologic and structural characterization of the dominant 66- to 73-kDa antigens of Borrelia burgdorferi

The 66- to 73-kDa proteins of Borrelia burgdorferi are dominant immunogens and expressed in all strains of B. burgdorferi. The humoral response to these Ag occurs relatively early during the course of infection. Two-dimensional Western blot analysis of this group of Ag revealed them to consist of a tetrad of proteins with apparent molecular mass of 66, 68, 71, and 73 kDa. Furthermore, in this study we demonstrate the 66-kDa protein to be a potent inducer of lymphoproliferation in the patient immune to B. burgdorferi. Monospecific polyclonal antibodies and mAb demonstrate that each of these proteins was immunologically distinct. However, direct amino acid sequence of the 66- and 68-kDa Ag was almost identical and had a high level of sequence similarity to the GroEL heat-shock protein (Hsp60) of Escherichia coli and the 60-kDa immunodominant protein of Treponema pallidum. The amino terminal sequence of the 71- and 73-kDa proteins of B. burgdorferi was almost identical and these proteins had remarkable sequence similarity to the DnaK heat-shock protein of E. coli (Hsp70). It appears likely, therefore, that proteins related to the heat-shock family are potent immunogens of B. burgdorferi.

An overview of the problem of toxoplasmosis and pneumocystosis in AIDS in the USA: implication for future therapeutic trials

By the end of 1989, 18,518 cases of Pneumocystis carinii infection and 5,614 cases of Toxoplasma gondii infection were reported to the Centers for Disease Control as the AIDS indicator disease. Pneumocystosis did not vary according to gender, race or risk factors; whereas toxoplasmosis was more common in black males with no known risk factors. Immigrants to the USA from Africa, Latin America and Haiti are three to four times more likely to develop toxoplasmic encephalitis than American-born patients with AIDS. The implications of this epidemiologic data for the predictive value of serology and clinical trials are discussed.

Treatment of acute toxoplasmosis with intravenous clindamycin. The California Collaborative Treatment Group

The interim results are presented of an ongoing large-scale, prospective, randomized study to determine the potential role of clindamycin in the treatment of toxoplasmic encephalitis. Patients were seropositive for Toxoplasma gondii antibodies and had clinical signs compatible with toxoplasmic encephalitis. Data was available on 33 patients, 15 of whom received pyrimethamine p.o./clindamycin i.v. and then p.o., and 18 of whom received pyrimethamine p.o./sulfadiazine p.o. The interim evaluation did not reveal a remarkable difference between the two regimens in the clinical or radiologic response. Adverse reactions to both regimens were common and frequently multiple, there being more adverse gastrointestinal reactions in patients on pyrimethamine/clindamycin and more adverse hematological reactions in those on pyrimethamine/sulfadiazine.

Overview of the clinical manifestations of Borrelia burgdorferi infection

Lyme disease, caused by the spirochete Borrelia burgdorferi, has classically been divided into three stages: erythema migrans; neurological or cardiac involvement; and arthritis. Rather than defining a set disease pattern, however, one should, more logically, conceptualize a progressive infection that may be localized or disseminated, acute or chronic. Erythema migrans, the earliest and most easily recognized manifestation of B burgdorferi infection, is an expanding annular erythematous skin lesion with a central clearing that develops soon after the bite of an infected ixodes tick. Musculoskeletal manifestations are common, with approximately one-half of untreated individuals developing arthritis. Of these, only 10% have chronic arthritis. Invasion of the central nervous system occurs as the infection disseminates hematogenously, with encephalitis, myelitis and meningopolyneuritis being the most severe results. Acute cardiac involvement is recognized in up to 8% of adult patients, and less often in children. Early antibiotic treatment of the infection is highly effective.

Amoxycillin plus probenecid versus doxycycline for treatment of erythema migrans borreliosis

72 adults with erythema migrans (early Lyme borreliosis) were enrolled in a randomised prospective trial comparing amoxycillin 500 mg plus probenecid 500 mg three times a day with doxycycline 100 mg twice a day for 21 days. These antibiotic regimens were chosen because of the known in-vitro sensitivity of Borrelia burgdorferi, the antibiotic tissue penetration, the pharmacokinetics of the drugs, and because the organism can disseminate early in the course of infection. 72 patients were evaluable (35 in the doxycycline group and 37 in the amoxycillin/probenecid group). The two regimens were equally effective for treatment of erythema migrans. Mild fatigue or arthralgia were the only post-treatment complaints, which resolved within 6 months. None of the patients needed further antibiotic treatment for Lyme borreliosis.

Penicillin-binding proteins in Borrelia burgdorferi

Penicillin-binding proteins were identified in Borrelia burgdorferi membranes. A 94-kilodalton penicillin-binding protein was the first to be labeled with tritiated penicillin and was the first band to disappear in a competition experiment. Its binding ability was destroyed when membranes were preboiled. In addition, several of these penicillin-binding proteins comigrated with bands previously identified as surface proteins.

Lyme neuroborreliosis. Peripheral nervous system manifestations

An ever increasing number of apparently unrelated peripheral nervous system (PNS) disorders has been associated with Lyme borreliosis. To ascertain their relative frequency and significance, we studied prospectively 74 consecutive patients with late Lyme disease, with and without PNS symptoms: 53% had intermittent limb paraesthesiae, 25% the carpal tunnel syndrome, 8% painful radiculopathy, and 3% Bell's palsy; 39% had disseminated neurophysiological abnormalities. To assess the interrelationships among these syndromes, we reviewed the neurophysiological findings in all 163 such patients that we have studied to date. Reversible abnormalities of distal conduction were the most common finding. Demyelinating neuropathy was extremely rare. The pattern of abnormality was similar in all patient groups, regardless of whether the symptoms suggested radiculopathy, Bell's palsy, or neuropathy. We conclude that (1) reversible PNS abnormalities occur in one-third of our patients with late Lyme borreliosis, and (2) the pattern of electrophysiological abnormalities is the same in all and is indicative of widespread axonal damage, suggesting that these different presentations reflect varying manifestations of the same pathological process.

Cross-antigenicity between the major surface proteins (ospA and ospB) and other proteins of Borrelia burgdorferi

Two of the major surface Ag of Borrelia burgdorferi, the 31-kDa OspA and 34-kDa OspB proteins, are encoded by a 49-kb plasmid. In this study, mAb and monospecific polyclonal antibodies were used to define cross-antigenicity of the OspA and OspB protein to each other and to other lower molecular mass proteins by Western blot analysis. Two mAb studied, 105.5 and 184.1, were directed predominantly against the 31-kDa OspA protein. However, each also reacted with other minor bands, though with different specificities. Using V8 protease digestion and cleavage by cyanogen bromide, we demonstrated that each mAb reacted to the 31-kDa protein differently. Monospecific polyclonal rabbit and human antibodies directed against the 34-, 31-, 22-, and 20-kDa proteins were eluted from blots and used to further corroborate the cross-reactivity among these Ag. Rabbit antibodies to the 31- and 22-kDa Ag gave remarkably similar peptide maps after V8 protease digestion of the 31-kDa OspA protein, as did mAb 184.1, suggesting that this mAb recognized an immunodominant epitope common to the 22- and 31-kDa proteins. It seems likely therefore that the humoral immune response to Borrelia surface Ag may be due to a limited number of cross-reactive epitopes on distinct, but related, gene products.

Cross-antigenicity between the major surface proteins (ospA and ospB) and other proteins of Borrelia burgdorferi

Two of the major surface Ag of Borrelia burgdorferi, the 31-kDa OspA and 34-kDa OspB proteins, are encoded by a 49-kb plasmid. In this study, mAb and monospecific polyclonal antibodies were used to define cross-antigenicity of the OspA and OspB protein to each other and to other lower molecular mass proteins by Western blot analysis. Two mAb studied, 105.5 and 184.1, were directed predominantly against the 31-kDa OspA protein. However, each also reacted with other minor bands, though with different specificities. Using V8 protease digestion and cleavage by cyanogen bromide, we demonstrated that each mAb reacted to the 31-kDa protein differently. Monospecific polyclonal rabbit and human antibodies directed against the 34-, 31-, 22-, and 20-kDa proteins were eluted from blots and used to further corroborate the cross-reactivity among these Ag. Rabbit antibodies to the 31- and 22-kDa Ag gave remarkably similar peptide maps after V8 protease digestion of the 31-kDa OspA protein, as did mAb 184.1, suggesting that this mAb recognized an immunodominant epitope common to the 22- and 31-kDa proteins. It seems likely therefore that the humoral immune response to Borrelia surface Ag may be due to a limited number of cross-reactive epitopes on distinct, but related, gene products.

Immunodiagnosis of Lyme borreliosis

The clinical definition of Lyme disease depends on the epidemiologic association of signs and symptoms with a measureable immune response to B. burgdorferi. The dependence on the demonstration of an immune response to B. burgdorferi has made the understanding of this systemic spirochetosis critical for the physician when making a diagnosis.

Biochemical and immunological characterization of the surface proteins of Borrelia burgdorferi

The immunodominant proteins and glycoproteins of Borrelia burgdorferi were analyzed by one-dimensional (1D) and 2D gel electrophoresis. More than 100 polypeptide species could be detected on silver-stained 2D gels. Separation of sonic extracts of the organism by differential centrifugation (100,000 X g) revealed several of the major proteins to reside predominantly within the pellet fraction. The antigenicity of the individual polypeptides was determined by Western (immuno-) blot analysis with sera from humans with chronic Lyme disease and from rabbits immunized with B. burgdorferi. Surface proteins of viable B. burgdorferi labeled with 125I or long-arm hydroxysuccinimide biotin were identified by gel analyses. Thirteen major surface proteins were apparent, including the highly immunogenic 41-kilodalton (kDa) endoflagellar antigen. Two of these proteins, with molecular masses of 22 and 41 kDa, were further characterized by electroblotting and microsequencing their amino termini. Significant (35%) homology between the first 20 amino acids of the 22-kDa protein and the deduced amino acid sequence of the 31-kDa (outer surface protein A) protein of B. burgdorferi may indicate that these proteins are processed similarly or are part of a gene family expressed at the surface of the organism. In addition, highly significant (88%) homology was found between the first nine amino acids of the 41-kDa protein of B. burgdorferi and the 33-kDa endoflagellar protein of Treponema pallidum, after which the sequences diverge. This observation provides in part a structural basis for the observed cross-reactivity between the two organisms and suggests alternative approaches to the development of specific immunodiagnostics.

Treatment of Lyme borreliosis

The infectious process of Lyme disease can appear as chronic dermatologic, rheumatologic, or neurologic. To rationally select a treatment regimen, the physician must have an appreciation of the clinical manifestations of the illness and of the systemic nature of the infection. The authors discuss the proper treatment protocols for each stage in the progression of Lyme disease.

Immunologic aspects of Lyme borreliosis

Immune responses to Borrelia burgdorferi infection are now well characterized. Following infection there is an early T cell response and a more slowly evolving B cell response. IgM antibodies appear first and are followed by IgG and IgA. Early antibodies are primarily against a 41-kilodalton flagellum-associated antigen; responses to other spirochetal antigens develop later. Serologic assays that use whole B. burgdorferi preparations are not always able to detect an early rise in antibodies above a background of crossreactive antibodies present in most uninfected individuals. Moreover, some individuals with neurologic involvement who lack diagnostic levels of serum antibody to B. burgdorferi have high levels of the antibody in their cerebrospinal fluid. Specific T cell blastogenesis to B. burgdorferi can further document infection. Analysis of T cell subsets in Lyme arthritis demonstrates a marked decrease in the CD4+2H4+ subpopulation in the synovial fluid, although normal numbers of these cells are present in peripheral blood. Immunologic measurements are useful in evaluating and treating a wide array of patients who may be infected with B. burgdorferi.

A perspective on the treatment of Lyme borreliosis

Lyme borreliosis has become the most common tick-borne infection in the United States. Although both beta-lactam and tetracycline antibiotics have been shown to be effective in the treatment of this spirochetosis, the development of optimal therapeutic modalities has been hampered by the lack of reliable microbiologic or immunologic criteria for the diagnosis or cure of this infection. In vitro sensitivity studies have been performed by several laboratories, but there has been no standardization of the methodology for measuring either inhibitory or bactericidal levels. Clinical studies have documented the efficacy of antibiotics, but therapy has failed in as many as 50% of cases of chronic infection. Although new antibiotic regimens appear promising, the optimal treatment of this infectious disease remains to be determined. In this report we review the clinical and experimental rationale for the antibiotic regimens that we currently use and the need for a more standardized approach to treatment trials.

Lyme neuroborreliosis: central nervous system manifestations

We evaluated 85 patients with serologic evidence of Borrelia burgdorferi infection. Manifestations included encephalopathy (41), neuropathy (27), meningitis (2), multiple sclerosis (MS) (6), and psychiatric disorders (3). We performed lumbar punctures in 53, brain MRI in 33, and evoked potentials (EPs) in 33. Only patients with an MS-like illness had abnormal EPs, elevated IgG index, and oligoclonal bands in the cerebrospinal fluid. Twelve of 18 patients with encephalopathy, meningitis, or focal CNS disease had evidence of intrathecal synthesis of anti-B burgdorferi antibody, compared with no patients with either MS-like or psychiatric illnesses, and only 2/24 patients with neuropathy. MRIs were abnormal in 7/17 patients with encephalopathy, 5/6 patients with an MS-like illness, and no others. We conclude that (1) intrathecal concentration of specific antibody is a useful marker of CNS B burgdorferi infection; (2) Lyme disease causes an encephalopathy, probably due to infection of the CNS; (3) MS patients with serum immunoreactivity against B burgdorferi lack evidence of CNS infection with this organism.

Carpal tunnel syndrome in Lyme borreliosis

Neurophysiologic evidence of median nerve entrapment in the carpal tunnel was present in 25% of patients with late Lyme borreliosis. Sixty-eight of 76 consecutive, prospectively studied patients with late Lyme underwent neurophysiologic testing. Nineteen reported intermittent hand paresthesias; 17 had neurophysiologically confirmed carpal tunnel syndrome. This was not consistently associated with clinically apparent wrist arthritis or with neurophysiologically evident peripheral neuropathy. We conclude that a significant proportion of patients with late Lyme borreliosis develop carpal tunnel syndrome.

Antibiotic treatment of Lyme borreliosis

Unlike most bacterial infections, where diagnosis is by identification of the causal organism, diagnosis of infection by Borrelia burgdorferi (Lyme's borreliosis) relies mostly upon indirect techniques. This situation has some short-comings. As long as no technology permits a microbiological diagnosis of this infection, controversy will exist as to the clinical symptoms and the criteria for the cure of the disease. Despite the lack of consensus upon both the clinical definition and the treatment of Lyme's borreliosis, it is widely agreed that the affection is best understood if regarded as a progressive general infectious disease. Indeed, following a bite with local infection, there occurs a fairly rapid dissemination of the spirochaetes. In vivo therapeutic trials have shown the potential effectiveness of beta-lactams and tetracyclines, but no treatment is considered universally effective. Most of the first trials were empirical, as antibiograms were not used. Antibiotic concentrations reached with some oral therapies are too low for the protection of certain sites such as the central nervous system. In vitro studies conducted on various strains of B. burgdorferi both in the US and in Europe are very enlightening. Among the more perplexing results of some of these studies, it is worth noting the high resistance rate of some B. burgdorferi strains to penicillin, reported by Johnson et al. and by Preac Mursic et al. Therapy for Lyme's borreliosis is discussed in light of both the in vivo and in vitro studies.

Seronegative Lyme disease. Dissociation of specific T- and B-lymphocyte responses to Borrelia burgdorferi

The diagnosis of Lyme disease often depends on the measurement of serum antibodies to Borrelia burgdorferi, the spirochete that causes this disorder. Although prompt treatment with antibiotics may abrogate the antibody response to the infection, symptoms persist in some patients. We studied 17 patients who had presented with acute Lyme disease and received prompt treatment with oral antibiotics, but in whom chronic Lyme disease subsequently developed. Although these patients had clinically active disease, none had diagnostic levels of antibodies to B. burgdorferi on either a standard enzyme-linked immunosorbent assay or immunofluorescence assay. On Western blot analysis, the level of immunoglobulin reactivity against B. burgdorferi in serum from these patients was no greater than that in serum from normal controls. The patients had a vigorous T-cell proliferative response to whole B. burgdorferi, with a mean ( +/- SEM) stimulation index of 17.8 +/- 3.3, similar to that (15.8 +/- 3.2) in 18 patients with chronic Lyme disease who had detectable antibodies. The T-cell response of both groups was greater than that of a control group of healthy subjects (3.1 +/- 0.5; P less than 0.001). We conclude that the presence of chronic Lyme disease cannot be excluded by the absence of antibodies against B. burgdorferi and that a specific T-cell blastogenic response to B. burgdorferi is evidence of infection in seronegative patients with clinical indications of chronic Lyme disease.

Experimental cryptosporidiosis in fetal lambs

Fetal lambs were infected in utero with purified sporulated oocysts of Cryptosporidium parvum in order to study pathogenesis and host cellular response to the enteropathogen. Ileal loops (IL) of fetuses, 124-130 days of gestation, were inoculated with 1-4 x 10(6) oocysts usually via cannulae in the abdominal wall of the ewe. Oocysts, both free and phagocytosed, were observed in the IL content as early as day 1 post-inoculation (PI). The percentage of oocysts phagocytosed by the host's polymorphonuclear neutrophils (PMN's) and mononuclear cells remained high up to day 13, the last day of examination. Numerous parasites were observed at days 6, 7, and 12 PI in the microvilli of the ileum with hypercellularity of the lamina propria, which consisted of a mixed infiltration of PMN's, mononuclear cells, including lymphoid cells, and a few eosinophils. Cytolysis and extrusion of epithelial cells, often heavily parasitized by various stages of the parasite, as well as inflammatory cells, were prominent in luminal contents. Germinal centers were prominent in mesenteric lymph nodes draining the infected loops by day 12 PI. Depletion of lymphoid cells was already present in Peyer's patches by day 4 PI.

New chemotherapeutic approaches in the treatment of Lyme borreliosis

1. It was demonstrated that while B. burgdorferi may be sensitive to relatively small concentrations of penicillin and ceftriaxone, the organism is killed slowly. This implies that, as in syphilis, prolonged blood levels of these drugs may be necessary in order to ensure cure. In contrast, the activity of tetracycline is more rapid in its action but is more dependent on drug concentration achieved. Unfortunately, the MIC and MBC for some strains are at or above the peak level achieved under optimal conditions. 2. Increasing the concentrations of penicillin or ceftriaxone above the MIC for the organism has little effect on the rate of killing. In contrast, the killing by tetracycline can be augmented by increasing concentrations of the drug. 3. Ceftriaxone is more active than penicillin, as measured by MIC, against the five strains of B. burgdorferi tested. 4. Ceftriaxone was efficacious in the treatment of Lyme borreliosis, which was recalcitrant to penicillin therapy. In a randomized trial comparing ceftriaxone to high-dose penicillin therapy, ceftriaxone was significantly more efficacious than penicillin in the treatment of the late complications of Lyme borreliosis.