FIG. 3.
Enhanced secretion of prostaglandins by R. rickettsii-infected EC. The levels of PGE2 and 6-keto-PGF1α in culture supernatants collected from uninfected controls and infected cells (Rr) at the indicated times were measured by an enzyme-linked immunosorbent assay. Also shown is a comparison of the effects of host cell interactions with viable (Rr) and heat-inactivated (Rr heated) or formalin-fixed (Rr FF) rickettsiae. Data points represent accumulated PG concentrations as means ± standard errors from at least three independent experiments. *, significant increase (P ≤ 0.05) in comparison to the baseline control level.