Western immunoblot and flagellum enzyme-linked immunosorbent assay for serodiagnosis of Lyme borreliosis

Lyme neuroborreliosis

Lyme neuroborreliosis (LNB) designates the nervous system disorders caused by the tick-borne spirochete Borrelia burgdorferi (Bb). The clinical syndromes are usually distinct and are classified as early and the rare late or chronic LNB. Early LNB occurs 3-6 weeks after infection most frequently as a lymphocytic meningoradiculoneuritis (LMR). Symptoms are mainly due to a painful sensory radiculitis and a multifocal motor radiculo-neuritis. Fifty percent have cranial nerve involvement predominantly uni- or bilateral facial nerve palsies. Meningitic symptoms occur primarily in children. Nerve biopsies, autopsies, animal models, and nerve conduction studies showed that the pathology is a lymphocytic perineuritis leading to multisegmental axonal injury of nerve roots, spinal ganglia, and distal nerve segments. Due to meningeal and root inflammation cerebrospinal fluid (CSF) shows lymphocytic inflammation. The only evidence that Bb causes peripheral neuropathy without CSF inflammation is seen in patients with acrodermatitis chronica atrophicans (ACA), a chronic dermatoborreliosis. In the rare chronic or late LNB the pathology and thus the clinical presentation is primarily due to chronic meningitis and meningovascular CNS involvement, whereas the peripheral nervous system is not primarily affected. In early and late LNB the diagnosis is based on a characteristic clinical appearance and CSF inflammation with Bb-specific intrathecal antibody production. Both conditions, but not the ACA-associated neuropathy, respond to antibiotic therapy.

Laboratory confirmation of Lyme disease

Lyme disease can be confirmed in the laboratory by isolation or detection of its causative agent, a tick-borne spirochete Borrelia burgdorferi, or by a diagnostic change in the titre of antibodies specific to the agent. B burgdorferi can be isolated and cultivated in Barbour-Stoenner-Kelly II medium. It can be detected by light microscopy in tissue sections or, rarely, in blood smears using various staining methods. There is interest in the development of alternative detection methods, including identification of specific antigens of B burgdorferi in the urine of suspected cases and demonstration of the presence of species-specific DNA using polymerase chain reaction assays. Currently, serological tests (indirect immunofluorescence assay, enzyme-linked immunosorbent assay and Western immunoblot) are the most practical and available methods for confirming Lyme disease. The quest to improve the specificity and sensitivity of serological tests - for example, through the use of specific recombinant antigens - continues.

Interpretation criteria for standardized Western blot for the predominant species of Borrelia burgdorferi sensu lato in China

OBJECTIVE

Western blotting (WB; immunoblotting) is a widely used tool for the serodiagnosis of Lyme borreliosis (LB), but so far, no generally accepted criteria for its performance and interpretation have been established in China. The present study was designed to determine the criteria for standardized Western blot for the predominant species of Borrelia burgdorferi sensu lato in China, in which WB was produced with strain PD₉₁ as the representative strain attributed to predominant genospecies Borrelia garinii of Borrelia burgdorferi sensu lato.

METHODS

Approximately 13 bands between 14 and 100 kD were differentiated for strain PD₉₁ by using Gel-Pro analysis software. In a study with 631 serum samples (taken from 127 patients with Lyme borreliosis and 504 controls), all observed bands were documented. To establish criteria for a positive WB result for strain PD₉₁, receiver operating characteristic (ROC) curves were used.

RESULTS

The following interpretation criteria were recommended: for IgG, at least one band of P83/100, P58, P39, P30, OspC, P17, P66, and OspA; for IgM, at least one band of P83/100, P58, OspA, P30, OspC, P17 or P41. In addition, syphilis, leptospirosis and other related diseases should be excluded when the positive band is P41 in IgM. For IgG criteria, the sensitivity is 73.2%, the specificity is 99.4% and Youden index is 0.726; for IgM criteria, the sensitivity is 50.6%, the specificity is 93.1% and Youden index is 0.437.

CONCLUSION

Standardization of WB assays is necessary for comparison of results from different laboratories. Moreover, the criteria of other genospecies of Borrelia burgdorferi sensu lato should be determined in the future to complete the criteria of WB for the diagnosis of the Lyme disease in China.

Improved serodiagnosis of Lyme disease

Aims-To determine whether enzyme linked immunosorbent assay (ELISA) results for Borrelia burgdorferi require confirmation by immunoblotting and how immunoblotting may best be used in the diagnosis of Lyme disease.Methods-Over one year, all referrals for Lyme disease to a district general hospital with a large tick population in its catchment area were tested by ELISA. Positive, low positive and negative serum samples were subjected to immunoblotting and the reactive bands analysed.Results-In total, 633 samples were received; 38 were ELISA positive and 97 low positive. More serum samples were from rural (n = 356) than from urban (n = 277) areas but a higher percentage of serum samples from urban areas were ELISA positive. The ELISA results were confirmed by immunoblotting in 15/38 positive samples but in only four of 37 with a low positive titre. An IgM positive blot required a 41 kDa band plus >/=1 specific band; for IgG a 41 kDa band plus >/=2 specific bands were necessary. Five serum samples were IgM positive with a 41 kDa plus one or more other specific bands. For IgG blots, the best discrimination was seen with the 21, 31, 46, and 92 kDa bands. Nonspecific, weakly reacting bands at 55, 60 and 67 kDa were frequently seen. Infection was confirmed in four of six patients with arthritis, but in only one of 10 patients with erythema chronicum migrans.Conclusions-ELISA alone is insufficient for diagnosis. All positive and low positive or negative serum samples with a good clinical history should be examined by immunoblotting. A higher percentage of modified ELISA positive than low positive results were confirmed. There are significant differences between European and American immunoblotting patterns. Local results show similarity to American results, highlighting the need for a local Borrelia isolate.

Simultaneous use of serum IgG and IgM for risk scoring of suspected early Lyme borreliosis: graphical and bivariate analyses

The laboratory diagnosis of early disseminated Lyme borreliosis (LB) rests on IgM and IgG antibodies in serum. The purpose of this study was to refine the statistical interpretation of IgM and IgG by combining the diagnostic evidence provided by the two immunoglobulins and exploiting the whole range of the quantitative variation in test values. ELISA assays based on purified flagella antigen were performed on sera from 815 healthy Danish blood donors as negative controls and 117 consecutive patients with confirmed neuroborreliosis (NB). A logistic regression model combining the standardized units of the IgM and IgG ELISA assays was constructed and the resulting disease risks graphically evaluated by receiver operating characteristic and 'predictiveness' curves. The combined model improves the discrimination between NB patients and blood donors. Hence, it is possible to report a predicted risk of disease graded for each individual patient, as is theoretically preferable. The predictiveness curve, when adapted to the local pretest probability of LB, allows high-risk and low-risk thresholds to be defined instead of cut-offs based on the laboratory characteristics only, and it allows the extent of under- and over-treatment to be assessed. It is shown that an example patient with low ELISA results in IgM and IgG, considered negative by the conventional cut-off, has a relatively high risk of belonging to the truly diseased population and a low risk of being false positive. Using a 20% high-risk threshold for advising the clinician to consider treatment, the sensitivity of the assay is increased from 76% to 85%, while the specificity is maintained at around 95%.

Place des méthodes biologiques dans le diagnostic des manifestations de la borréliose de Lyme

Lyme borreliosis (LB) is a multisystemic infection transmitted by ticks. Its diagnosis is based on clinical and biological criteria. These criteria could be different in Europe than in the USA, because of the existence of multiples strains of borrelia in Europe. In primary stage of LB, the diagnosis is often clinical. In the secondary stage, LB diagnosis is established with an Elisa serology confirmed by a Western blot. The interpretation criteria of these laboratory tests should follow European recommendations (EUCALB). LB with neurological involvement should be confirmed by screening for intrathecal synthesis of borrelia antibodies in CSF. LB with rheumatologic expression could be confirmed by screening for borrelia in joint fluid by PCR. There is no strong marker of activity of the disease. Follow-up for LB is difficult, because antibodies may persist for years and LB does not confer immunization.

Tick-borne encephalopathies : epidemiology, diagnosis, treatment and prevention

Tick-borne encephalopathies constitute a broad range of infectious diseases affecting the brain and other parts of the CNS. The causative agents are both viral and bacterial. This review focuses on the current most important tick-borne human diseases: tick-borne encephalitis (TBE; including Powassan encephalitis) and Lyme borreliosis. Rocky Mountain spotted fever (RMSF) and Colorado tick fever (CTF), less common tick-borne diseases associated with encephalopathy, are also discussed. TBE is the most important flaviviral infection of the CNS in Europe and Russia, with 10 000-12 000 people diagnosed annually. The lethality of TBE in Europe is 0.5% and a post-encephalitic syndrome is seen in over 40% of affected patients, often producing a pronounced impairment in quality of life. There is no specific treatment for TBE. Two vaccines are available to prevent infection. Although these have a good protection rate and good efficacy, there are few data on long-term immunity. Lyme borreliosis is the most prevalent tick-borne disease in Europe and North America, with >50 000 cases annually. Localised early disease can be treated with oral phenoxymethylpenicillin (penicillin V), doxycycline or amoxicillin. The later manifestations of meningitis, arthritis or acrodermatitis can be treated with oral doxycycline, oral amoxicillin or intravenous ceftriaxone; intravenous benzylpenicillin (penicillin G) or cefotaxime can be used as alternatives. The current use of vaccines against Lyme borreliosis in North America is under discussion, as the LYMErix vaccine has been withdrawn from the market because of possible adverse effects, for example, arthritis. RMSF and CTF appear only in North America. RMSF is an important rickettsial disease and is effectively treated with doxycycline. There is no treatment or preventative measure available for CTF.

Peptide-based OspC enzyme-linked immunosorbent assay for serodiagnosis of Lyme borreliosis

Sera from 210 patients with Lyme borreliosis (LB) were studied by an enzyme-linked immunosorbent assay (ELISA) based on a synthetic peptide (pepC10) comprising the C-terminal 10-amino-acid residues of OspC of Borrelia burgdorferi. We found that 36.3 and 45.0% of the serum samples from patients with erythema migrans (EM) and neuroborreliosis (NB), respectively, displayed immunoglobulin M (IgM) anti-pepC10 reactivities, while these samples rarely (</=8%) displayed IgG antibody reactivities. Sera from patients with acrodermatitis chronica atrophicans did not contain anti-pepC10 antibodies. The diagnostic performance of this newly developed peptide ELISA was compared with those of an ELISA based on the full-length recombinant OspC protein (rOspC) and a commercially available ELISA based on the B. burgdorferi flagellum (Fla). The sensitivity of the IgM pepC10 ELISA was slightly lower (P < 0.04) than that of the rOspC ELISA for EM patients (36.3 versus 43.8%), while there was no difference for NB patients (45.0 versus 48.0%). However, the optical density values obtained by the pepC10 ELISA were generally higher than those obtained by the rOspC ELISA, leading to a significantly better quantitative discrimination between seropositive patients with NB and controls (P < 0.008). The specificity of the pepC10 ELISA was similar to those of the rOspC ELISA and the Fla ELISA for relevant controls including patients with syphilis and mononucleosis. Although the overall diagnostic sensitivity of the Fla ELISA was superior, 8.8 and 12.0% of the EM and NB patients, respectively, were antibody positive only by the pepC10 ELISA. Thus, use of a diagnostic test for LB based on the detection of IgM antibodies to pepC10 and Fla has increased sensitivity for the diagnosis of early LB.

Enzyme-linked immunosorbent assay using recombinant OspC and the internal 14-kDa flagellin fragment for serodiagnosis of early Lyme disease

The outer surface protein C (OspC) and the internal 14-kDa flagellin fragment of strain GeHo of Borrelia burgdorferi sensu stricto were expressed as recombinant proteins in Escherichia coli and were purified for use in an immunoglobulin M (IgM) enzyme-linked immunosorbent assay (OspC-14-kDa antigen ELISA). No hint at disturbing protein-protein interferences, which might influence the availability of immunoreactive epitopes, was found when the recombinant antigens were combined in the ELISA. The recombinant OspC-14-kDa antigen ELISA was compared to a commercial IgM ELISA that used a detergent cell extract from Borrelia afzelii PKo as the antigen. According to the manufacturer's information, the cell extract contains, in addition to other antigens, the following diagnostically relevant antigens: the 100-kDa (synonyms, 93- and 83-kDa antigens), 41-kDa, OspA, OspC, and 17-kDa antigens. The specificity was adjusted to 95% on the basis of data for 154 healthy controls. On testing of 104 serum samples from patients with erythema migrans (EM), the sensitivity of the recombinant ELISA (46%) for IgM antibodies was similar to that of the commercial ELISA (45%). However, when 42 serum samples from patients with polyclonal B-cell stimulation due to an Epstein-Barr virus infection were tested, false-positive reactions were significantly less frequent in the recombinant ELISA (10%) than in the whole-cell-extract ELISA (23%). OspC displays sequence heterogeneity of up to 40% according to the genomospecies. However, when the reactions of serum specimens from controls and EM patients with OspC from representative strains of B. burgdorferi sensu stricto (strain GeHo) and B. afzelii (strain PKo) were compared in an ELISA, almost no differences in specificity and sensitivity were seen. This demonstrates that the sera predominantly recognize the common epitopes of OspC tested in this study. In conclusion, we suggest that the OspC-14-kDa antigens ELISA is a suitable test for the detection of an IgM response in early Lyme disease.

Immunoblot reactivity of polyclonal and monoclonal antibodies with periplasmic flagellar proteins FlaA1 and FlaB of porcine Serpulina species

The periplasmic-flagellum (PF) proteins of Triton X-100-soluble and Triton X-100-insoluble sodium dodecyl sulfate-treated fractions from reference and field strains of Serpulina hyodysenteriae, Serpulina innocens, and Serpulina pilosicoli were characterized by Western blotting with a rabbit polyclonal antibody (PAb) specific for the 44-kDa PF sheath protein of S. hyodysenteriae (Z. Li, F. Dumas, D. Dubreuil, and M. Jacques, J. Bacteriol. 175:8000-8007, 1993) and a murine monoclonal antibody (MAb), designated 7G2, specific for the PF core FlaB proteins of S. hyodysenteriae. The MAb 7G2 reacted with a conserved epitope present in the 37-, 34-, and 32-kDa PF core FlaB proteins of all Serpulina species. This suggested that the core FlaB proteins are conserved among porcine Serpulina species. An immunoreactive band of approximately 44 kDa was present with all S. hyodysenteriae, S. innocens, and S. pilosicoli strains that were reacted with the PAb. The specificities of the PAb and the MAb for the FlaA1 and FlaB proteins of Serpulina species were confirmed by N-terminal amino acid sequencing of 44- and 37-kDa proteins, respectively, of S. hyodysenteriae and S. pilosicoli. Results from this study provide further evidence that the 44-kDa protein FlaA1 and the 37-, 34-, and 32-kDa FlaB proteins are conserved among porcine Serpulina species.

Immunoblot interpretation criteria for serodiagnosis of early Lyme disease

We monitored the antibody responses of 55 treated patients with early Lyme disease and physician-documented erythema migrans. Six sequential serum samples were obtained from patients before, during, and until one year after antibiotic therapy and analyzed by in-house enzyme-linked immunosorbent (ELISA) and immunoblot assays. An immunoblot procedure utilizing a gradient gel and an image analysis system was developed. A relational database management system was used to analyze the results and provide criteria for early disease immunoblot interpretation. Recommended criteria for the immunoglobulin M (IgM) immunoblot are the recognition of two of three proteins (24, 39, and 41 kDa). The recommended criteria for a positive IgG immunoblot are the recognition of two of five proteins (20, 24 [> 19 intensity units], 35, 39, and 88 kDa). Alternatively, if band intensity cannot be measured, the 22-kDa protein can be substituted for the 24-kDa protein with only a small decrease in sensitivity. Monoclonal antibodies were used to identify all these proteins except the 35-kDa protein. With the proposed immunoblot interpretations, the sequential serum samples were examined. At visit 1, the day of diagnosis and initiation of treatment, 54.5% of the serum samples were either IgM or IgG positive. The peak antibody response, with 80% of the serum samples positive, occurred at visit 2, 8 to 12 days into treatment. The sensitivities of the IgM and IgG immunoblot for detecting patients that were seropositive into the study period were 58.5 and 54.6%, respectively, at visit 1 and 100% at visit 2. Twenty percent of the patients remained seronegative throughout the study. The specificities of the IgM and IgG immunoblots were 92 to 94% and 93 to 96%, respectively. The IgM immunoblot and ELISA were similar in sensitivities, whereas the IgG immunoblot had greater sensitivity than the IgG ELISA (P = 0.006).

Comparison of four immunoserologic assays for detection of antibodies to Borrelia burgdorferi in patients with culture-positive erythema migrans

In view of the significant sequelae associated with Lyme borreliosis, there is a need for timely and accurate diagnosis of erythema migrans (EM). Although Borrelia burgdorferi can be cultured from biopsies of EM lesions, immunodiagnostic testing is more widely available. Four immunoserologic methods were studied by using the sera of 51 patients with EM lesions that were culture positive for B. burgdorferi. Nineteen patients had single primary lesions, and thirty-two had multiple secondary lesions. At the time of biopsy, 40 patients, 8 with primary lesions and all patients with secondary lesions, were seropositive by an immunoglobulin M (IgM) indirect fluorescent-antibody (IgM IFA) test (Bion Enterprises). Twenty-three patients were seropositive by a whole-cell fluorescence enzyme immunoassay (EIA) (BioWhittaker, Inc.), twenty-two were positive by immunoblotting (ViroStat, Inc.), and one was positive by a P39 recombinant EIA (P39 EIA) (General Biometrics, Inc.). Sera from various patient control groups were tested: rheumatoid arthritis (n = 19), infectious mononucleosis (n = 20), systemic lupus (n = 22), syphilis (n = 13), streptococcal sequelae (n = 20), and healthy subjects (n = 16). None of these sera reacted with the IgM IFA test or P39 EIA. Fifteen reacted with the fluorescence EIA. We conclude that the IgM IFA test is an effective and reliable assay for the diagnosis of EM, particularly for patients with secondary lesions. Immunoblot, fluorescence EIA, and P39 EIA lack the sensitivity to reliably diagnose EM.

Recombinant immunoblot in the serodiagnosis of Lyme borreliosis. Comparison with indirect immunofluorescence and enzyme-linked immunosorbent assay

A recombinant immunoblot was developed for detection of IgM and IgG antibodies in patients with Lyme borreliosis. The recombinant antigens were the chromosomal-encoded Borrelia burgdorferi proteins p100, the flagellin and an internal flagellin fragment thereof as well as the plasmid-encoded outer surface proteins A (OspA) and C (OspC). A panel of 144 sera from patients with Lyme borreliosis (erythema migrans, n = 31; neuroborreliosis state II, n = 60; Lyme arthritis, n = 24 and acrodermatitis chronica atrophicans, n = 19) have been investigated and the results have been compared to the immunofluorescence absorption test (IFA-ABS) and to two different enzyme-linked immunosorbent assays [the flagellin ELISA and a newly developed ELISA (OGP-ELISA)]. The two ELISAs were comparable in sensitivity, whereas the IFA-ABS was less sensitive for IgM antibody but equally sensitive for IgG antibody detection. Immunoblot analysis revealed that IgG antibodies are mainly reactive with p100 and the internal flagellin fragment (sensitivity 51% and 32%, respectively) and rarely with OspC (14%). All patients with late Lyme borreliosis had IgG antibodies against the p100. IgM antibodies were predominantly directed against OspC (43%) and in a lower extent against the internal flagellin fragment and p100 (15% and 13%, respectively). The complete flagellin was not useful due to a high number of unspecific reactions with control sera and the OspA was only exceptionally reactive in Lyme borreliosis patients. The sensitivity of IgM antibody detection could be increased in cases with early Lyme borreliosis from 46% to 65% when the OspC blot was performed in addition to the flagellin ELISA, or from 56% to 65% when performed in addition to the OGP-ELISA. The recombinant blot is, therefore, a valuable diagnostic test to increase sensitivity of early antibody detection and is regarded as a valuable confirmatory test also in late disease.

Cross-reactivity between B. burgdorferi and other spirochetes affects specificity of serotests for detection of antibodies to the Lyme disease agent in dogs

Western immunoblots, the kinetics-based enzyme-linked immunosorbent assay (KELA), and the microagglutination test were used to evaluate cross-reactivity among antibodies to serovars of Leptospira interrogans (leptospiral serovars), and B. burgdorferi from naturally infected dogs, and to Serpulina (Treponema) hyodysenteriae from vaccinated rabbits. Whole-cell lysates from Borrelia spp., leptospiral serovars, and Serpulina spp. were used for SDS-PAGE, western blots, and KELA. Crossreactivity occurred between the antibodies to B. burgdorferi and leptospiral serovars when tested on the heterologous antigens. Antibodies to leptospiral serovars tended to cross-react more strongly with antigens of B. burgdorferi spp. than did antibodies to B. burgdorferi when tested against antigens of leptospiral serovars. The antibodies against B. burgdorferi showed a lesser degree of cross-reactivity to the antigens of S. hyodysenteriae and S. innocens than they did to leptospiral serovars. We conclude that cross-reactivity occurs between B. burgdorferi and leptospiral serovars. Validation and interpretation of ELISA tests for detection of antibody activity to whole cell lysates of the Lyme agent must take this cross-reactivity into consideration. Conversely, dogs infected with the Lyme agent do not show significant cross-reactivity in the microagglutination test for antibody to the leptospiral serovars.

Immunological and molecular polymorphisms of OspC, an immunodominant major outer surface protein of Borrelia burgdorferi

The gene of the immunodominant major protein pC of Borrelia burgdorferi was previously cloned and sequenced (R. Fuchs, S. Jauris, F. Lottspeich, V. Preac-Mursic, B. Wilske, and E. Soutschek, Mol. Microbiol. 6:503-509, 1992). pC is abundantly expressed on the outer surface of B. burgdorferi, as demonstrated by immunoelectron microscopy with monoclonal antibody L22 1F8. Accordingly, pC is renamed OspC, by analogy to the outer surface proteins OspA and OspB. Western immunoblot analysis of 45 B. burgdorferi isolates with monoclonal antibodies revealed that OspC is immunologically heterogeneous. Partial sequence analysis of the ospC gene confirmed the protein heterogeneity at the genetic level. We found that the degree of identity between the ospC partial sequences of five strains representing different OspA serotypes was only 63.3 to 85.4%. Immunological heterogeneity was also observed among representatives of the three newly designated genospecies of B. burgdorferi sensu lato, B. burgdorferi sensu stricto, B. garinii, and group VS461. Heterogeneity was confirmed for B. garinii at the genetic level. The ospC gene was also cloned from strains that did not express OspC, and antibody-reactive OspC was expressed in Escherichia coli. In addition, OspC-expressing variants were obtained from a nonexpressing strain by plating single colonies on solid medium. These findings confirm that the ospC gene is also present in nonexpressing strains. Because OspC is an immunodominant protein for the early immune response in Lyme borreliosis and was effective as a vaccine in an animal model, the immunological and molecular polymorphisms of ospC and OspC have important implications for the development of diagnostic reagents and vaccines.

Intrathecal synthesis of anti-Borrelia burgdorferi antibodies in neuroborreliosis: a study with special emphasis on oligoclonal IgM antibody bands

Pre- and post-treatment (up to 3-26 months after antibiotic therapy) humoral immune responses were investigated in five neuroborreliosis patients. Anti-Borrelia (B.) burgdorferi IgG and IgM antibodies in CSF and serum were quantitated by capture ELISA. Agarose gel isoelectric focusing (AIF) and protein blotting were used to detect oligoclonal IgG and IgM bands as well as oligoclonal anti-B. burgdorferi IgG and IgM antibodies. These latter components were visualized by transfer to antigen-coated membranes (immunoblot) and immunoenzymatic staining. By ELISA, intrathecal anti-B. burgdorferi IgG and IgM antibody synthesis was detected in all initial specimens and continued 3-26 months after antibiotic therapy in four and three cases, respectively. AIF with protein blotting showed oligoclonal bands of total IgG as well as total IgM in the initial CSF specimens of all patients and persistence of such components occurred in four and five cases, respectively. By AIF and immunoblot, oligoclonal anti-B. burgdorferi IgG and IgM antibody bands could be detected in the CSF of every patient. IgG antibody bands were present in all initial CSF samples. The first specimen of one patient was negative for IgM antibody bands but such components appeared 3 weeks later. Oligoclonal CSF anti-B. burgdorferi IgG antibody components persisted over the entire follow-up periods in all but one case where they disappeared 6 weeks after treatment. The oligoclonal IgM antibodies in CSF vanished in two cases (after being present up to 4 and 11 months after antibiotic therapy) while they persisted over the entire (3-6 months after antibiotic therapy) follow-up periods in three cases. The specificity of the IgM antibody immunoblot technique was corroborated by control experiments, including antibody absorption studies and use of 41 kDa flagellar antigen.

Comparison of whole-cell antibodies and an antigenic flagellar epitope of Borrelia burgdorferi in serologic tests for diagnosis of Lyme borreliosis

A recombinant protein (p41-G) of an antigenic region of flagellin was used in a standard and amplified enzyme-linked immunosorbent assay (ELISA) to detect antibodies to Borrelia burgdorferi, the causative agent of Lyme borreliosis. Comparable sensitivities (88 to 94%) were noted when sera from 17 persons who had erythema migrans and antibodies to whole-cell B. burgdorferi were tested against the p41-G antigen. In tests of a second study group of 36 persons who had erythema migrans but no detectable antibodies to whole-cell B. burgdorferi, 3 (8%) were positive when the p41-G antigen was used. Assay specificity likewise increased when the p41-G fragment was included in an ELISA with human sera containing treponemal antibodies. Recombinant flagellar proteins of B. burgdorferi, such as the p41-G antigen, can be used in an ELISA and may help confirm Lyme borreliosis during early stages of infection and improve specificity.

Prognostic B-cell epitopes on the flagellar protein of Borrelia burgdorferi

Overlapping decapeptides based on the flagellin sequence of Borrelia burgdorferi B31 (G. S. Gassmann, M. Kramer, U. B. Göbel, and R. Wallich, Nucleic Acids Res. 17:3590, 1989) were used to identify immunologically reactive regions of flagellin. Five serum specimens from patients with late manifestations of Lyme disease and borrelia-specific monoclonal antibody H9724 reacted with an epitope in the central region of the flagellar protein (amino acids 205 to 226), which is heterologous to the amino acid sequences of other bacterial flagellins. This epitope was not recognized by human sera with antibodies to Treponema pallidum, sera of healthy individuals, or sera from patients with stage I or II of Lyme disease.

Ovalbumin blocking improves sensitivity and specificity of immunoglobulin M immunoblotting for serodiagnosis of patients with erythema migrans

To improve the serodiagnosis of erythema migrans, we evaluated how sensitivity and specificity of immunoblotting are influenced by antigen concentration and blocking conditions. We found that an antigen concentration of 0.5 micrograms per lane in concert with ovalbumin blocking of the nitrocellulose provided the best results. In this case, 81% of the erythema migrans had positive immunoglobulin M tests, whereas only 33% were positive in a flagellum enzyme-linked immunosorbent assay (ELISA) and 28% were positive in a sonicate ELISA.