In Mice, Tuberculosis Progression Is Associated with Intensive Inflammatory Response and the Accumulation of Gr-1dim Cells in the Lungs

Infection with Mycobacterium tuberculosis (Mtb) results in different clinical outcomes ranging from asymptomatic containment to rapidly progressing tuberculosis (TB). The mechanisms controlling TB progression in immunologically-competent hosts remain unclear.To address these mechanisms, we analyzed TB progression in a panel of genetically heterogeneous (A/SnxI/St) F2 mice, originating from TB-highly-susceptible I/St and more resistant A/Sn mice. In F2 mice the rates of TB progression differed. In mice that did not reach terminal stage of infection, TB progression did not correlate with lung Mtb loads. Nor was TB progression correlated with lung expression of factors involved in antibacterial immunity, such as iNOS, IFN-gamma, or IL-12p40. The major characteristics of progressing TB was high lung expression of the inflammation-related factors IL-1beta, IL-6, IL-11 (p<0.0003); CCL3, CCL4, CXCL2 (p<0.002); MMP-8 (p<0.0001). The major predictors of TB progression were high expressions of IL-1beta and IL-11. TNF-alpha had both protective and harmful effects. Factors associated with TB progression were expressed mainly by macrophages (F4-80(+) cells) and granulocytes (Gr-1(hi)/Ly-6G(hi) cells). Macrophages and granulocytes from I/St and A/Sn parental strains exhibited intrinsic differences in the expression of inflammatory factors, suggesting that genetically determined peculiarities of phagocytes transcriptional response could account for the peculiarities of gene expression in the infected lungs. Another characteristic feature of progressing TB was the accumulation in the infected lungs of Gr-1(dim) cells that could contribute to TB progression.In a population of immunocompetent hosts, the outcome of TB depends on quantitatively- and genetically-controlled differences in the intensity of inflammatory responses, rather than being a direct consequence of mycobacterial colonization. Local accumulation of Gr-1(dim) cells is a newly identified feature of progressing TB. High expression of IL-1beta and IL-11 are potential risk factors for TB progression and possible targets for TB immunomodulation

CONTROL OF THE ADHESION QUALITY OF NIRESIST INSERTION IN CASTINGS OF DIESEL ENGINES FORCER

The results of researches of an ultrasonic quality testing of pistons of diesel engines in casting are submitted. It is shown, that special focusing transducers should carry out for the testing. Accuracy of the testing is not worse than 0,5 % from the area of niresist insert

THE RESULTS OF USING OF INDICATORS OF THE HIGH-TEST CAST IRON OF TYPE ICH STRUCTURE IN CONDITIONS OF PRODUCT

The results of development of the indicator of highstrength pig-iron are submitted in the report. The indicator using allows to carry out the testing of the pig-iron structure in conditions of manufacture without additional preparation of the casting surface

REGULATION OF IMMUNE RESPONSE AGAINST MYCOBACTERIUM TUBERCULOSIS BY THE POPULATION OF REGULATORY DENDRITIC CELLS

On the background of a high level of genetic susceptibility to tuberculosis infection (TB), granulomatous reactions in the lung  tissue fail to effectively isolate infection foci and rather result in  diffuse pathology, confluence of granulomata and  formation of  necrotic zones. Uncontrolled inflammation severely affect breathing  function of the lung. Thus, effective disease control requires a good  balance between protective and pathogenic immune responses.  Immature regulatory dendritic cells (DCreg) and regulatory T  lymphocytes (Treg) represent a pool of important cellular regulators  of inflammation. Earlier we have demonstrated that stromal lung  cells support development of CD11b+CD11clowCD103– DCreg from  their bone marrowderived precursors in in vitro cultures. In addition,  significantly larger population size and more rapid  development of the lung CD4+Foxp3+ Treg cells characterize TB- resistant B6 mice compare to their TB-susceptible I/St counterparts.  Here, we report that adoptive transfer of DCreg cells into TB-infected I/St mice is capable to enlarge the population of Treg cells in the  lungs. This, in turn, attenuates lung pathology, decreases  mycobacterial multiplication and diminishes lung infiltration with  neutrophils, i.e., selectively restricts the population of cell largely  responsible for TB pathogenesis. The key difference in lung  pathology between DCreg recipients and control animals was the  lack of tissue-destructive foci and necrotic zones in the former  group. Meanwhile, the groups of mice did not differ in production of  regulatory (IL-10 and TGF-β) and key inflammatory (IFNγ and IL-6)  cytokines by lung cells. The latter result suggests that contact rather  than secretory mechanisms underlie moderate attenuation of  the TB process in the lungs of mice with an elevated lung Treg level,  given that plethora of such mechanisms were described for Treg  functioning. Although therapeutic effects were relatively weak, our  results indicate that cell therapy approaches are applicable to  regulation of lung tissue inflammation during TB course

B6 and I/St mice differ in numbers (<i>P</i>< 0.05-0.01 at different time points, Student’s <i>t</i>-test) of regulatory (A) and activated (B) CD4⁺ T cells in mediastinal, lung-draining lymph nodes throughout the course of infection.

<p>B6 and I/St mice differ in numbers (<i>P</i>< 0.05-0.01 at different time points, Student’s <i>t</i>-test) of regulatory (A) and activated (B) CD4⁺ T cells in mediastinal, lung-draining lymph nodes throughout the course of infection.</p

Capacity of Lung Stroma to Educate Dendritic Cells Inhibiting Mycobacteria-Specific T-Cell Response Depends upon Genetic Susceptibility to Tuberculosis

<div><p>The balance between activation and inhibition of local immune responses in affected tissues during prolonged chronic infections is important for host protection. There is ample evidence that regulatory, tolerogenic dendritic cells (DC) are developed and present in tissues and inhibit overwhelming inflammatory reactions. Also, it was firmly established that stromal microenvironment of many organs is able to induce development of immature regulatory DC (DCreg), an essential element of a general immune regulatory network. However, direct experimental data demonstrating inhibition of immune responses by stroma-instructed immature DCreg in infectious models are scarce, and virtually nothing is known about functioning of this axis of immunity during tuberculosis (TB) infection. In this study, we demonstrate that lung stromal cells are capable of supporting the development in culture of immature CD11b⁺CD11c^lowCD103^- DCreg from lineage-negative (lin^-) bone marrow precursors. DCreg developed on lung stroma isolated from mice of genetically TB-hyper-susceptible I/St and relatively resistant B6 inbred strains inhibited proliferative response of mycobacteria-specific CD4⁺ T-cell lines a dose-dependent manner. Importantly, the inhibitory activity of B6 DCreg was substantially higher than that of I/St Dcreg. Moreover, when the donors of stromal cells were chronically infected with virulent mycobacteria, the capacity to instruct inhibitory DCreg was retained in B6, but further diminished in I/St stromal cells. DCreg-provided suppression was mediated by a few soluble mediators, including PGE₂, NO and IL-10. The content of CD4⁺Foxp3⁺ Treg cells in the mediastinal, lung-draining lymph nodes at the advanced stages of chronic infection did not change in I/St, but increased 2-fold in B6 mice, and lung pathology was much more pronounced in the former mice. Taken together, these data provide genetic evidence that the capacity to maintain populations of regulatory cells during <i>M. tuberculosis</i> infection is a part of the host protective strategy.</p> </div

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 (∼ 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)-α 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

DCreg developed on lung stroma from naïve (N) TB-resistant (A) B6 mice are more potent inhibitors of T cell response than their counterparts from TB-susceptible (B) I/St mice (<i>P</i><0.01, ANOVA).

<p>Inhibitory activity of DCreg developed on stromal cells from infected (Inf) animals was almost fully retained in B6 (A), but significantly (<i>P</i><0.05, ANOVA) dropped in I/St mice (B). Mean triplicate CFU counts ± SD from 4 independent experiments and per cent of inhibition are displayed.</p

Soluble mediators of DCreg suppressor activity.

<p>(A) - B6 DCreg with blocked PGE₂ production are less inhibitory compared to control cells (25-40% decrease in inhibition depending on the content of DCreg in culture, P<0.05, ANOVA), but still retain suppressor activity. (B) - Both B6 and I/St cell-free supernatants possessed inhibitory activity regarding T cell proliferation, but in I/St this activity is weaker (P<0.01, ANOVA). (C) - NO production: similar nitrite levels in B6 and I/St co-cultures with lung stroma from naïve mice and opposite shifts in the presence of infected stroma – slight decrease in I/St, but 2-fold increase in B6 cultures, resulting in 3-fold (<i>P</i><0.01, ANOVA) differences. (D) - The content of IL-10 is significantly (P=0.04, Student’s <i>t</i>-test) higher in B6 compared to I/St supernatants developed on infected stroma. Mean triplicate CFU counts ± SD from 3 independent experiments are displayed.</p

3 mo post aerosol infection with ~100 <i>M. tuberculosis</i> H37Rv CFU I/St mice display substantially more severe infectious course compared to B6 mice.

<p>(A) -1 log difference in lung CFU counts (N=5, P<0.001, ANOVA, 1 experiment of 3 similar); (B) – more prominent gross pathology of the lung and greater splenomegaly; (C) – granulomata with necrotizing centers (arrows) are present in the lungs of I/St but not of B6 mice (X25).</p