[Heterogeneity of canine immune responses to Borrelia burgdorferi in a line immunoassay comprising recombinant VlsE and C 6 peptide].

OBJECTIVE: The study aimed to investigate the distribution of specific immune responses (IgG) to Borrelia burgdorferi using a line immunoassay with recombinant VlsE (variable major protein-like sequence, expressed) protein and synthetic C peptide among other antigens. We compared the immune responses to VlsE protein and C6 peptide, because both antigens have been considered specific for a Borrelia infection.

MATERIALS AND METHODS: A total of 1355 blood samples from dogs suspected of Borrelia infection were analysed. The line immunoassay employed nine antigens.

RESULTS: A total of 64.4% of all samples tested negative, 16.4% were positive for an infection and 17.4% were positive for vaccination. Band patterns specific for both infection and vaccination were observed in 1.2% of the dogs. The bands that most frequently tested positive were p100 (24.3%), p31/OspA (18.5%), C6 (16.3%) and VlsE (13.9%). A total of 236 dogs (17.4% of the population) had antibodies to VlsE and/or C6 peptide. In 73.3% of these dogs, results for VlsE and C6 peptide were consistent, whereas this was not the case for 26.7% of these animals.

CONCLUSION AND CLINICAL RELEVANCE: Testing using a line immunoassay allows for qualitative analyses of different immune responses to various antigens used as probes. In our study, >  26% of the dogs displayed discrepant results with regard to VlsE and C6 , the two antigens considered specific for Borrelia burgdorferi infection. To confirm or rule out infection, the results of several band patterns, thought to be specific for infection, need to be taken into consideration.