The goal of this work was to elucidate the mechanism of direct interaction of bacterial cells with tumor necrosis factor (TNF-alpha; cytokine). It was shown earlier that this interaction facilitated activation of bacterial growth and recultivation of non-cultivated forms in vitro and in vivo. It was shown in experiments with mice deficient in the genes encoding eucaryotic TNF-alpha receptors and infected with salmonella that addition of exogenous TNF-alpha to suspension of infection cells caused a one-day acceleration in the infection start (bacteria planting from spleen) in both knockouted and control mice relative to the same animals infected with the same bacteria without cytokine. Thus, bacteria are able to interact with cytokine even in the absence of eucaryotic receptors. Specificity of the bacterium-cytokine interaction and bacterial protein EF-Tu mediating direct interaction of bacteria with cytokine were identified using the method of immobilization of recombinant protein TNF-alpha-spacer-CSD on cellulose.
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