Antibodies against specific proteins of and immobilizing activity against three strains of Borrelia burgdorferi sensu lato can be found in symptomatic but not in infected asymptomatic dogs

In an area where Lyme disease is endemic in The Netherlands all dogs had po sitive titers by whole-cell enzyme-linked immunosorbent assay and appeared to be naturally infected by Borrelia burgdorferi sensu late. To compare the antibody responses of symptomatic dogs and asymptomatic controls, we perfo rmed Western blots and in vitro immobilization assays to study antibody-dep endent bactericidal activity, Strains from three different genospecies were employed as the antigen source: B, burgdorferi strain B31, Borrelia garini i strain A87S, and Borrelia afzelii strain pKo, Antibodies against flagelli n (p41) and p39 for three strains were found in sera from both symptomatic and asymptomatic dogs and were therefore considered to be markers of exposu re, Antibodies against p56 and p30 of strain B31, against p75, p58, p50, Os pC, and p<19 of strain A87S, and against p56, p54, p35, OspB, p31, p26, and p<19 of strain pKo were found significantly more frequently in sera from s ymptomatic dogs younger than 8 years when the first symptoms were observed than in those from age-matched controls (P < 0.01), These antibodies were n ot found in preclinical sera and appeared during development of disease. An tibodies against OspA of strains B31 and A87S were only seen in acute-phase and convalescent sera from three dogs that recovered from disease. Incubat ion with 25% normal canine serum did not result in the immobilization of st rains B31 and pKo, but partial immobilization of strain A87S (61% +/- 24%; [standard deviation] at 5 h) occurred, Seven of 15 sera from symptomatic do gs but none of the sera from II asymptomatic dogs had antibody-dependent im mobilizing activity against one of the strains, Consecutive sera from one o f these dogs immobilized two different strains. Antibody-mediated bacterici dal serum was not seen before onset of disease, was strongest in the acute phase of disease, and fluctuated during chronic disease. From seven out of eight symptomatic dogs Borrelia DNA was amplified by PCR; in three of them the bactericidal activity was directed against one of the genospecies ampli fied from that dog; however, four PCR-positive dogs lacked bactericidal act ivity, In conclusion, dogs with symptomatic canine borreliosis have more-ex tensive antibody reactivity against Borrelia, as shown by both Western blot ting and immobilization assays.