Fig. 4.

Inducible nitric oxide synthase (iNOS) induction by p66⁺ versus Δp66 B. burgdorferi. Ea.hy926 endothelial cells were incubated with either p66⁺ or Δp66 B. burgdorferi at an MOI of 10 or with no bacteria. After 1 or 3 h, the cell layers were washed and lysed, and iNOS protein levels in cell lysates were measured using a commercially available ELISA kit. The values are the means plus standard deviations (error bars) of three replicate samples from a single representative experiment. At the 3-h time point, comparing the value for Δp66 B. burgdorferi-infected cells to the value for p66⁺ B. burgdorferi-infected cells yielded a P value of <0.02, and comparing the value for Δp66 B. burgdorferi-infected cells to the value for the uninfected control at the 3-h time point yielded a P value of 0.03. At 1 h, there were no significant differences, and there was no significant difference between the uninfected and the p66⁺B. burgdorferi-infected cell samples at 3 h.