DEPs Induce Local Ige Class Switching Independent of Their Ability to Stimulate iBALT de Novo Formation

BACKGROUND

Diesel exhaust particles (DEPs) are leading to a general increase in atopic diseases worldwide. However, it is still unknown whether DEPs induce systemic B-cell IgE class switching in secondary lymphoid organs or locally in the lungs in inducible bronchus-associated lymphoid tissue (iBALT). The aim of this work was to identify the exact site of DEP-mediated B-cell IgE class switching and pro-allergic antibody production.

METHODS

We immunized BALB/c mice with different OVA doses (0.3 and 30 µg) intranasally in the presence and absence of two types of DEPs, SRM1650B and SRM2786. We used low (30 µg) and high (150 µg) DEP doses.

RESULTS

Only a high DEP dose induced IgE production, regardless of the particle type. Local IgE class switching was stimulated upon treatment with both types of particles with both low and high OVA doses. Despite the similar ability of the two standard DEPs to stimulate IgE production, their ability to induce iBALT formation and growth was markedly different upon co-administration with low OVA doses.

CONCLUSIONS

DEP-induced local IgE class switching takes place in preexisting iBALTs independent of de novo iBALT formation, at least in the case of SRM1650B co-administered with low OVA doses.

Early IgE Production Is Linked with Extrafollicular B- and T-Cell Activation in Low-Dose Allergy Model

Despite its paramount importance, the predominant association of early IgE production with harmless antigens, via germinal-center B- and T-cell subpopulations or extrafollicular activation, remains unresolved. The aim of this work was to clarify whether the reinforced IgE production following the subcutaneous immunization of BALB/c mice with low antigen doses in withers adipose tissue might be linked with intensified extrafollicular or germinal-center responses. The mice were immunized three times a week for 4 weeks in the withers region, which is enriched in subcutaneous fat and tissue-associated B cells, with high and low OVA doses and via the intraperitoneal route for comparison. During long-term immunization with both low and high antigen doses in the withers region, but not via the intraperitoneal route, we observed a significant accumulation of B220-CD1d-CD5-CD19+ B-2 extrafollicular plasmablasts in the subcutaneous fat and regional lymph nodes but not in the intraperitoneal fat. Only low antigen doses induced a significant accumulation of CXCR4+ CXCR5- CD4+ extrafollicular T helpers in the withers adipose tissue but not in the regional lymph nodes or abdominal fat. Only in subcutaneous fat was there a combination of extrafollicular helper accumulation. In conclusion, extrafollicular B- and T-cell activation are necessary for early IgE class switching.

[Comparative characteristics of root formation and mineralization features in the permanent teeth according to cone beam computed tomography data]

AIM

Studying features of root formation and mineralization in permanent teeth of children and adults.

MATERIAL AND METHODS

The root formation features were studied in 2800 children's permanent teeth aged 6-15 in Moscow and Moscow region; cone beam computed tomography was performed according to the orthodontic indications. CBCT method was also used to study the apical foramen diameter, width of the permanent teeth periodontal fissure, perform clinical examination and treatment of youngsters and young people (aged 12-25, n=180) with pulpitis (K04.03), apical periodontitis (K04.5) and uncompleted processes of hard tissues mineralization and hard tissues with different degrees of maturation; as well as groups of adults (aged 30-50, n=170) with pulpitis (K04.03) and apical periodontitis (K04.5) in permanent teeth with completed processes of hard tissues mineralization.

RESULTS

CBCT is objective for visualizing teeth of both jaws which allows determining root formation stages in children's permanent teeth and high precision during one examination visit. Teeth Youngster's and young peopl's teeth have expressed anatomical and structural features during 5-6 years after root formation completion: apical foramen diameter of 0.71±0.004 mm, periodontal fissure width of 1.01±0.004 mm, hard tissues density in apical part of root is 12282.71 units HU, which is different from analogous readings in people over 25 where they make 0.61±0.004 mm (p<0.05); 0.71±0.003 mm (p<0.05); 1428.6±0.89 units HU (p<0.05) respectively.

CONCLUSION

CBCT is a useful tool for visualization of dental roots allowing precise definition of root developmental stage in permanent teeth in children by one diagnostic imaging procedure.

Coherent Stokes and anti-Stokes high-order components generation by biharmonic pumping via stimulated low-frequency Raman scattering

In this Letter, we report on experimental effective coherent multiple Stokes and anti-Stokes high-order components generation by Stokes pulse injection at the process of stimulated low-frequency Raman scattering. This process can be used for effective generation the tunable spectral comb consisting of several equidistant spectral lines separated by a constant frequency spacing of several GHz.

Study of Immunomodulatory Effects of Extracellular HSP70 in a Mouse Model of Allergic Airway Inflammation

Immunostimulatory properties of extracellular heat shock proteins 70 kDa (HSP70) became interesting for investigators a long time ago. However, in recent years a series of works showing a significant relation of the immunostimulating effects of recombinant HSP70 to contamination of the protein samples with bacterial endotoxins (lipopolysaccharide, LPS) has been published. The authors showed that intensive elimination of LPS from the protein samples resulted in inversion of immunostimulating effects of HSP70 to immunosuppressive activity of the protein. Nevertheless, at present the conception of immunostimulating, proinflammatory action of extracellular HSP70 is the most common. In this work, we studied immunomodulatory effects of exogenous HSP70 in a mouse model of allergic inflammation of airways. We also analyzed the dynamics of the level of the extracellular pool of HSP70 in the site of inflammation. The results demonstrated a considerable content of extracellular HSP70 in bronchoalveolar lavages with dynamics reflecting the stages of development of the induced inflammation. Oropharyngeal injection of exogenous HSP70 in the acute phase of allergic inflammation of airways resulted in significant suppression of the inflammatory process, which conforms to published data demonstrating an immunosuppressive activity of the extracellular pool of HSP70.

[Modulating Effect of Extracellular HSP70 on Generation of Reactive Oxigen Species in Populations of Phagocytes]

Reactive oxygen species (ROS) produced by phagocytic cells of the innate immune system play an important role in the first line of defense protecting the host from pathogens. The NADPH oxidase multi-subunit complex is the main source of ROS in all types of the phagocytes. Formation of the membrane-associated enzyme complex and its activity are dependent on many different factors controlling both intensification and suppression of the ROS production rate. However, the evidences are emerging in recent years indicating existence of poorly studied mechanisms of restriction of ROS generation level in phagocytes directed at protection of host tissues in the sites of inflammation from destruction caused by the oxygen free radicals. Our previous data and results of other authors demonstrate that a mechanism of the limitation of ROS production by phagocytes may by connected with immunomodulating activity of extracellular pool. of HSP70. In the present work, we used inhibitors of NADPH oxidase and in vitro cultures of different phagocytes to study a possible relationship between down-regulating effect of exogenous HSP70 on ROS generation and the interaction of the protein with the enzyme subunits. Our results confirmed the literature data concerning the ability of extracellular HSP70 to modulate NADPH oxidase activity and demonstrated for the first time an inhibitory effect of the protein on intracellular ROS generation in phagocytes.

[Dynamics of indicators of the "skin window" and change in body reactivity upon trauma]

The dynamics of indicators of the "skin window" was studied in 118 patients with fractures of the bones. The dynamics of changes of the indicators was found to correspond to severity of the trauma. The picture of dermocytograms in patients with complications was different as compared with that of patients without complications. The method can be used for the estimation of reactivity of the organism in clinical practice.

[Dynamics of indicators of dermocytograms and reparative capacity of the body in burns]

The investigation of dermocytograms by a modified method of the "skin window" in 101 patients with different square surfaces of deep burns has shown that the dynamics of mononuclear content is dependent on the injury degree. Lower parameters of mononuclear content in dermocytograms during the course of treatment correspond to the disturbance of reparative capacities of the organism in groups of patients with the complicated course of the disease. The "skin window" test can be used for the treatment since it shows the degree of the burn trauma dynamics and character of its course, facilitates the prognosis of complications.