||Borrelia burgdorferi IgG ELISA (recombinant).
|# of Samples
||1 x 96 Assays.
||The recombinant Borrelia burgdorferi IgG-ELISA is intended for the qualitative determination of IgG class antibodies against Borrelia burgdorferi in human serum or plasma (citrate) offering increased diagnostic specificity and sensitivity by employing immunodominant antigens. In combination with the recombinant IgM ELISA each clinical phase of Lyme disease - from Erythma chronicum migrans over Bannwarth-Syndrom up to Lyme arthritis - may be detected even in borderland cases providing unerring results and diagnostic aid for the clinical staff.
||Spirochetes are motile bacteria with a periplasmatic axial filament. All pathogenic species belong to the family Treponemataceae, which includes the three genera: Treponema, Borrelia, and Leptospira. The Treponemae are extremely long, flexible, filamentous cells that are usually held in a characteristic spiral, or coiled-spring shape. Borreliae are the largest Treponemataceae with very coarse and irregular spirals. Borrelia burgdorferi, the causative agent of Lyme disease, is transmitted mainly by ticks but probably also by other blood-sucking insects. Habitats are the wooded, humid and temperate regions of North America, Europe, North Africa, Australia and Japan; foresters, farmers, and anybody entering infested forests may be affected.
The degree of contamination of ticks amounts to 3-60% dependent on seasonal and regional differences; up to 30% of the population may be infected (about 1500 cases annually in USA, several hundred in Europe).
Because of its multisystemic character, unequivocal diagnosis of Lyme disease is difficult. Only early detection permits efficient control by antibiotics, since in the chronic phase borreliae are nearly inaccessible.
The presence of bacteria resp. infection may be identified by
Microscopy: Giemsa or Wright-stained blood smears.
PCR Serology: Detection of antibodies by IF, ELISA, immunoblotting.
|Principles of the assay
||The major constituent of B.burgdorferi flagella is flagellin (41 kDa, p41). Whereas the lipoprotein OspC (22 kDa, p22) within the outer membrane of the spirochete induces an early antibody formation in the ECM-phase of Lyme disease, the species-specific markers p100, p18 and VlsE are especially reliable for detecting the IgG response and they are responsible for the high sensitivity. P41i is included in the presented antigens to avoid cross reactivity with antibodies of syphilitic sera.
The Borrelia burgdorferi IgG-ELISA contains the recombinant epitope OspC of the phylum B31 (B. sensu stricto), 20047 and T25 (B. garinii), p100, and p18 of the phylum PKo (B. afzelii) and p41i of the phylum PBi (B. garinii).
Microtiter strip wells are precoated with recombinant Borrelia burgdorferi antigens. Diluted patient specimens and ready to use controls are added to these wells and antibodies recognizing the immobilized B. burgdorferi antigen bind during the first incubation. After washing the wells to remove all unbound sample and control material horseradish peroxidase labelled anti-human IgG conjugate is added. During a second incubation this conjugate binds to the captured antibodies, and the excess unbound conjugate is removed by a further wash step. The immune complex formed by the bound conjugate is visualized with TMB Substrate Solution which gives a blue reaction product, the intensity of which is proportional to the amount of B. burgdorferi-specific IgG antibody in the patient specimen. Sulphuric acid is added to each well to stop the reaction. This produces a yellow endpoint colour. Absorbance at 450 nm is read using an ELISA microwell plate reader.
|Storage and Stability
||The reagents are stable up to the expiry date stated on the label when stored at 2-8°C.
|Limitations of the Test
||Bacterial contamination or repeated freeze-thaw cycles of the specimen may affect the absorbance values. Diagnosis of an infectious disease should not be established on the basis of a single test result. A precise diagnosis should take into consideration clinical history, symptomatology as well as serological data. In immunosuppremized patients and newborns serological data only have restricted value.
A neg. result (IgG or IgM) cannot exclude an infection with B. burgdorferi. Especially in the early phase of infection there is the possibility that none or no detection quantities of the antibodies do exist. In the case of infection or a grey zone result we recommend a further sample after 2-3 weeks. A positive result of IgG does not always mean that an acute infection exists because the antibodies of a previous infection can persist. The use of recombinant antigens avoid extensively cross reactions with the following antibodies: Treponema pallidum, Leptospira, Borrelia recurrentis. Antibodies of a lues-infection to p41i were occasionally determinated. Therefore a lues-infection should be excluded.
||Johnson R.C., Schmid G.P., Hyde F.W., Steigerwaldt A.G., Brenner D.J.(1984) Borrelia burgdorferi sp.nov.:etiologic agent of Lyme disease.Int J Syst Bacteriol 34,496-497AsbrinkE., Hovmark A.(1988) Early and late cutaneous manifestations of Ixodes-born borreliosis (erythema migrans borreliosis, Lyme Borreliose).Ann NY Acad Sci 539,4-15Karlson M., Hovind-Hougan K., Svenungsen B., Stiernsted G.(1990) Cultivation and characterization of Spirochetes from cerebrospinal fluid of patients with Lyme borreliosis. J Clin Microbiol 28, 473-479Preac-Mursicd V.,Wilske B., Schierz G. (1986) Eurpean Borrelia Burgdorferi isolated from human and ticks:Culture conditions and antibiotic susceptibility.Zbl Bakt Hyg A 263,112-118Wilske B., Preac-Mursic V.,Fuchs R., Schierz G.(1990) Diagnostik der Lyme Borreliose.Diagnose und Labor,Laboratoriumsblätter 40,24-36Wilske B. (2003) Diagnosis of Lyme Borreliosis in Europe. Vector-Borne and Zoonotic Diseases 3 (4), 215 ? 227Jauris-Heipke S. et al. (1990): Osp17, a novel immunodominant outer surface protein of Borrelia afzelli: recombinant expression in Escherichia coli and its use as a diagnostic antigen for serodiagnosis of Lyme borreliosis. Med Microbiol Immunol 187, 213 ? 219Schulte-Spechtel U. et al. (2003) Signifikant Improvement of the Recombinant Borrelia-Specific Immunoglobulin G Immunoblot Test by Addition of VlsE and a DbpA Homologue Derived from Borrelia garinii for Diagnosis of Early Neuroborreliosis. J. Clin Mircrobiol 41, 1299 ? 1303Eicken C. et al. (2002) Crystal Structure of Lyme Disease Variable Surface Antigen VlsE of Borrelia burgdorferi. J. Biol Chem 277, 21691 ? 21696Wang D., Botkin D.J. and Norris S.J.(2003) Characterisation of the vls antigenic variation loci of the Lyme disease spirochaetes Borrelia garinii Ip90 and Borrelia afzelii ACAI. Mol Microbiol 47 (5), 1407 ? 1417Ohnishi J. et al. (2003) Genetic Variation at the vlsE Locus of Borrelia burgdorferi within Ticks and Mice over the Course of a Single Transmission Cycle. J. Bacteriol 185, 4432 - 4441.