Phospholipase A activity associated with the growth of Rickettsia prowazekii in L929 cells

Publisher Website
Google Scholar
Abstract
Cultured L929 cells infected with Rickettsia prowazekii had a greatly increased rate of hydrolysis of fatty acid from the oleic acid-radiolabeled phospholipids of the host cell membranes. The incorporation of fatty acid into phospholipid in an infected cell was only moderately inhibited relative to a mock-infected cell. Thus, even if the release of fatty acid from phospholipid represented a steady state between hydrolysis and resynthesis of phospholipids, the increase in release of fatty acid was due principally to increased phospholipase A activity. The increased rate of hydrolysis did not occur only late in the rickettsial infection; this activity began early in infection and continued throughout the course of infection. The addition of tetracycline or chloramphenicol (antibodies which inhibit rickettsial protein synthesis) to the infected cells caused a rapid and total abatement of this increased rate of phospholipid hydrolysis. In contrast, high concentrations of penicillin affected the morphology of the intracellular rickettsiae, but did not inhibit the phospholipase activity. The phospholipase A activity clearly damages the host cell during the rickettsial infection and may represent the activity by which R. prowazekii escapes from the host cell.