Figure 6: Lipid priming is protective against bacterial colonization of ticks.

(a–h) Five replicates of 1 × 10⁵ ISE6 cells were transfected with siRNA molecules targeting components of the I. scapularis immune system. (a,c,e,g) Silencing efficiency or (b,d,f,h) A. phagocytophilum load was measured for the components of the (a–d) IMD, (e–f) Toll and (g–h) JAK-STAT pathways. Transfected cells were incubated with 1 ng of indicated lipids for 6 h and infected with A. phagocytophilum at MOI 50. Bacterial burden was quantified and normalized against β-actin. Data are represented as the mean±standard errors of the means (SEM). Analysis of variance (ANOVA)-Dunnet; Student’s t-test. *P<0.05. NS, not significant. (−), non-stimulated. Data are representative of 5 biological replicates and two technical replicates. (i) D. andersoni ticks were mock- or lipid-injected (1 ng). Ticks were allowed to feed in individual group patches on a splenectomized, acute, A. marginale-infected calf for six days. Midguts from individual ticks were assessed for A. marginale infection levels by quantitative reverse transcriptase–PCR. Bacterial burden was quantified and normalized against β-actin. Samples represent the mean of 15-20 individual ticks±s.e.m. ANOVA-Dunnet. *P<0.05. NS, not significant. (−), non-primed. See also Supplementary Fig. 6 and Supplementary Tables 2 and 3.