Z O O E C O . O R GZ O O E C O . O R GA defined mixture of recombinant antigens from several Borrelia genospecies improves serodiagnosis of Lyme disease
Soutschek, E., Krämer, B., Wassenberg, D., Hechtfischer, A.
MIKROGEN GmbH, Fraunhoferstr. 20, 82152 Martinsried
E-mail: soutschek@mikrogen.de
The use of recombinant Borrelia antigens in standardized test systems like ELISA (recomWell) and Westernblot (recomBlot) is well documented. The immunodominant antigens p100/p83, p58, p41, p39, OspA, OspC, Osp17/p18, internal flagellin fragments or VLSE are well characterized and can be used in serological applications. Beside choosing the right antigen combination, assay procedure (e. g. stringency of buffers, incubation time) and test interpretation are decisive for high specificity and sensitivity.
One major drawback of conventional assay procedures based on bacterial lysates of selected strains is the variable gene expression and the lack of standardization therefore. Also the heterogenous immune response against different Borrelia burgdorferi subtypes remains unsolved. The sequence variability of the outer surface proteins like OspA and OspC is the main cause for this finding. Aim of this investigation was to produce by genetechnological means immunodominant antigens of different Borrelia genospecies and serotypes and test them with clinically defined patient sera. In particular OspC antigens of seven Borrelia garinii strains (PBr, PTrob, PBi, PHei, TN, T25, 20047) and one representative strain each of Borrelia afzelii (PKo) and Borrelia burgdorferi sensu stricto (B31) were serologically characterized. Sera of Lyme Borreliosis patients, especially of patients with neuroborreliosis, often react only with antigens of one selected Borrelia garinii strain. It is notable that the IgG response is more strain specific than the IgM response. The results of these investigations finally lead to an improved combination of recombinant Borrelia antigens from several genospecies for serodiagnosis. By improving the sensitivity of serological testing the reduction of possibly false negative assay results is most important for the patients.