** ND = not done. Figure 2 Borrelia burgdorferi flaB DNA copies per mg tissue weight (means ± standard deviations) in PCR-positive Tariquidar concentration Tissues summarized in Tables find more 2 and 3 , including sub-inoculation site (subIN), heart base (HB), ventricular muscle (VM), quadriceps muscle
(Quad) and tibiotarsus (Tibio) from C3H mice inoculated with wild-type (white bars) compared to arp null Δarp3 B. burgdoferi (black bars) at day 14 (a), day 28 (b) and day 42 (c) of infection. (*, P ≤ 0.05) ND: not determined. A confirmatory experiment was performed in which groups of 4 C3H mice were inoculated with 106 wild-type or Δarp3 spirochetes, and then necropsied on day 28 to verify the difference in tissue spirochete burdens in heart base, ventricular muscle, quadriceps muscle, and tibiotarsal tissue. Tissues were not collected for histopathology. In wild-type infected mice, 4/4 inoculation sites and 3/4 urinary bladders SYN-117 order were culture-positive, and 3/3 inoculation sites (one sample contaminated) and 0/4 urinary
bladders were culture-positive in Δarp3 infected mice. Spirochete burdens were significantly lower (P ≤ 0.05) in tissues of Δarp3 infected mice compared to wild-type infected mice, including sub-inoculation site (139 ± 266 SD vs. 1,761 ± 1,682 SD), heart base (45 ± 54 SD vs. 2,333 ± 1,400 SD), ventricular muscle (28 ± 26 SD vs 448 ± 276 SD), and quadriceps muscle (15 ± 23 SD vs 367 + 291 SD). Spirochete burdens were also lower in tibiotarsus tissue of Δarp3 infected mice (13 ± 11 SD vs 16,171 ± 29,765 SD), but differences were not statistically different (P = 0.16). Based upon these observations, it was determined that both C3H-scid mice as well as C3H mice infected with Δarp3 had lower spirochete burdens in tissues. Sera from C3H mice that were confirmed to be culture-positive at 60 days of infection with wild-type or Δarp3 spirochetes PtdIns(3,4)P2 were determined to be appropriately sero-reactive against recombinant
Arp antigen (Arp seropositive or seronegative, respectively). Serum antibody titers from Δarp3 infected mice were equivalent to antibody titers in mice infected with wild-type infected mice when tested against B. burgdorferi lysate antigen (≥1:24,300), and antibody titers to recombinant Arp antigen were verified to be either negative (Δarp3) or positive (Δarp3 + lp28-1G), with titers equivalent to Arp titers in wild-type immune sera (1:2,700). Larval ticks were fed upon the before-mentioned wild-type or Δarp3 infected C3H mice 3 days before necropsy at day 42. Replete ticks were allowed to molt and harden into nymphs, and then tested by Q-PCR for flaB and arp DNA. Among ticks that fed upon wild-type infected mice, 30/30 were PCR positive for both flaB and arp, with 53,950 mean ± 84,668 SD flaB copy numbers per tick.