Diphtheria Toxin Pretreatment of Mice Prior to Borrelia Infection

Lyophilized diphtheria toxin (DTx) from Corynebacterium diphtheriae (1 mg; EMD Millipore) was resuspended in filter-sterilized PBS and stored at −80 °C. Mice were injected intraperitoneally with 1 µg of DTx in 50 µL PBS, or with PBS alone, for two consecutive days prior to infection with B. burgdorferi. Groups consisted of BALB/c DEREG mice administered DTx in PBS with or without subsequent infection, BALB/c DEREG mice administered PBS prior to infection, and wild-type BALB/c mice administered DTx in PBS prior to infection. Mice were weighed immediately before administration of DTx and then regularly thereafter for the duration of the studies. Mice were anesthetized with isoflurane prior to all injections.