Protein synthesis in HeLa or Henle 407 cells infected with Shigella dysenteriae 1, Shigella flexneri 2a, or Salmonella typhimurium W118

The incorporation of [14C]leucine into protein was studied in two mammalian cell lines which had been infected with strains of Shigella dysenteriae 1, Shigella flexneri 2a, or Salmonella typhimurium W118. These cell lines differed in susceptibility to the effects of exogenously applied Shiga cytotoxin. All invasive shigella strains (which synthesize this toxin to a greater or lesser degree) were found to inhibit protein synthesis in both cell lines with equal efficiency. Leucine accumulation continued in these cells, but the labeled amino acid was preferentially incorporated into bacterial protein. S. typhimurium W118, which has not been shown to elaborate a Shiga-like toxin, had little effect on protein synthesis in infected host cells.