Leptospira spp.  vaccinal antibodies do not react with Borrelia burgdorferi peptides used in the AccuPlex 4. 
We attempted to determine if Leptospira spp.  antibodies induced by vaccination would cross-react with Borrelia burgdorferi antigens used in a commercial automated immunofluorescent assay (AccuPlex 4 BioCD; Antech).  Staff- and student-owned dogs ( n = 31) were recruited at a veterinary teaching hospital in a B. burgdorferi nonendemic area.  The dogs were randomized and administered 1 of 4 commercial Leptospira spp.  vaccines that contained serovars Canicola, Grippotyphosa, Icterohaemorrhagiae, and Pomona, then booster vaccinated 3 wk later.  Blood was collected on weeks 0, 3, 4, 8, and 12.  After confirming that maximal Leptospira spp.  titers occurred on week 4, aliquots of sera from week 4 were shipped frozen for analysis of B. burgdorferi antibodies against OspA, OspC, OspF, P39, and SLP with the AccuPlex system.  Week 4 sera from all 31 dogs had a titer of 1:100 for at least 1 Leptospira spp.  serovar.  Titers of 1:800 or greater were detected against multiple serovars in 27 dogs.  None of the samples contained antibodies against the B. burgdorferi OspA, OspC, OspF, P39, and SLP peptides used in the commercial assay.  The B. burgdorferi peptides used in the AccuPlex system do not recognize naturally occurring Leptospira spp.  antibodies or those induced by the commercial Leptospira spp.  vaccines administered in our study.