ENZYME-LINKED-IMMUNOSORBENT-ASSAY AND IMMUNOBLOT ANALYSIS FOR DETECTION OF ANTIBODIES TO BORRELIA-BURGDORFERI IN DOGS - THE IMPACT OF SERUMABSORPTION WITH HOMOLOGOUS AND HETEROLOGOUS BACTERIAE

Sera from 665 apparently healthy dogs were examined for antibodies to the Lyme disease spirochete Borrelia (B.) burgdorferi by using an ELIS A with a whole cell sonicate of B. burgdorferi sensu stricto reference strain B31 (ATCC 35210) as antigen. To discover false positive reacti ons due to the unsatisfactory specificity of conventional enzyme-linke d immunosorbent assays for B. burgdorferi, sera were absorbed in paral lel with both B. burgdorferi and a heterologous sorbent consisting of whole cells of Escherichia coli, Salmonella typhimurium. and eight ser ovars of Leptospira interrogans. The difference between optical densit ies obtained in the ELISA after serum absorption with the heterologous sorbent and the B. burgdorferi sorbent was defined as a new value, '' ODdiff'', for ELISA reactivity specific for B. burgdorferi. ELISA resu lts were confirmed by immunoblot studies. By testing unabsorbed sera, 48 of 665 serum samples (7.2%) were considered ELISA positive. 37 of t hese 48 sera (77.1%) were apparently false positive: here a similar re duction of ELISA reactivity was obtained after absorption with B. burg dorferi antigen and with the heterologous sorbent (ODdiff similar to 0 ). None of these 37 sera gave immunoblot patterns characteristic for c anine B. burgdorferi infection.