[Mechanism of interaction of tumor necrosis factor (TNF-alpha) of macroorganism with the Salmonella enterica cells (ser. Typhimurium)].

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.

Mycobacterium tuberculosis-susceptible I/St mice develop severe disease following infection with taxonomically distant bacteria, Salmonella enterica and Chlamydia pneumoniae.

Mice of I/St strain develop severe lung inflammation and die shortly following infection with virulent mycobacteria. To find out whether tuberculosis (TB)-susceptible I/St mice are susceptible to other intracellular bacteria, we investigated two different taxonomically distant pathogens, Chlamydia pneumoniae and Salmonella enterica serovar Typhimurium. Comparison of I/St and TB-resistant A/Sn mice (both Nramp1(r)) demonstrated that the former are more susceptible to both salmonella and chlamydia, displaying a significantly shortened survival time following challenge. Lung pathology develops more rapidly in I/St compared to A/Sn mice following infection with chlamydia, despite their similar ability to control bacterial multiplication. Following infection with salmonella, substantial ( approximately 3 log) but very short (second day post-infection) interstrain differences in bacterial loads were observed, accompanied by higher levels of interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha in the peritoneal cavities of I/St mice. I/St macrophages were more permissive for salmonella growth during the first 24 h following infection in vitro. Because the prominent differences in survival time did not correlate with permanent differences in bacterial multiplication, we suggest that both infections trigger fatal pathological processes whose dynamics depend strongly upon the host genetics.

[The role of tumor necrosis factor-alfa in the interaction between the macro- and microorganism].

The authors present a review containing their own and literature data on the role of cytokine TNF-alfa in infectious process on the part of the macro- and microorganism, paying special attention to the latter. The paper contains data from literature concerning the mechanism of the interaction between cytokine and eukaryotic cells and experimental data on direct interaction between cytokine and bacterial cells in vitro and in vivo.

[Influence of tumor necrosis factor on the growth of vegetative and nonculturable forms of Salmonella]. / Vliianie factora nekroza opukholi na razmnozhenie vegetativnykh i nekul'tiviruemykh form sal'monell.

The growth rate of the vegetative forms and the recultivation rate of the uncultivable forms of Salmonella isogenous strains, one of these strains carrying mutation in gene pqi, were studied. The multiplication rate of the vegetative and uncultivable forms of Salmonella control strain in the spleen of infected animals at the initial stages of the infectious process was shown (in vivo) to be considerably accelerated after the preliminary incubation of the culture with cytokine (tumor necrosis factor). The multiplication rate, in vivo and in vitro, of Salmonella vegetative and uncultivable forms with mutation in gene pqi did not change after the incubation of the cells with cytokine, which is indicative of an important role played by the product of this gene in the process of the interaction of bacteria with cytokines. The full nucleotide sequence Salmonella gene pqi was determined.