Inhibition of Rickettsia conorii growth by recombinant tumor necrosis factor alpha: enhancement of inhibition by gamma interferon.
Purified human recombinant tumor necrosis factor alpha (rTNF-alpha) inhibited the growth of Rickettsia conorii (Casablanca strain) in HEp-2 cell culture. The effect was observed when the cells were pretreated with rTNF-alpha or when rTNF-alpha was added after adsorption of the rickettsiae. The inhibitory effect of rTNF-alpha on rickettsial growth was enhanced by gamma interferon. Cycloheximide had no effect on inhibition of the rickettsial yield, suggesting that de novo protein synthesis is not required for the inhibitory effect of rTNF-alpha. The addition of tryptophan partially abolished the inhibitory effect of rTNF-alpha and rTNF-alpha plus gamma interferon.
Manor
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Faculty of Health Sciences-Soroka Medical Center, Ben-Gurion University of the Negev, Beer Sheva, Israel.
Sarov
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D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology*; D011994:Recombinant Proteins; D012281:Rickettsia / Q000254:growth & development*; D012282:Rickettsia Infections / Q000276:immunology; D014364:Tryptophan / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D014364:Tryptophan