Ablation of lysozyme M-positive cells prevents aircraft noise-induced vascular damage without improving cerebral side effects.

Aircraft noise induces vascular and cerebral inflammation and oxidative stress causing hypertension and cardiovascular/cerebral dysfunction. With the present studies, we sought to determine the role of myeloid cells in the vascular vs. cerebral consequences of exposure to aircraft noise. Toxin-mediated ablation of lysozyme M+ (LysM+) myeloid cells was performed in LysMCreiDTR mice carrying a cre-inducible diphtheria toxin receptor. In the last 4d of toxin treatment, the animals were exposed to noise at maximum and mean sound pressure levels of 85 and 72 dB(A), respectively. Flow cytometry analysis revealed accumulation of CD45+, CD11b+, F4/80+, and Ly6G-Ly6C+ cells in the aortas of noise-exposed mice, which was prevented by LysM+ cell ablation in the periphery, whereas brain infiltrates were even exacerbated upon ablation. Aircraft noise-induced increases in blood pressure and endothelial dysfunction of the aorta and retinal/mesenteric arterioles were almost completely normalized by ablation. Correspondingly, reactive oxygen species in the aorta, heart, and retinal/mesenteric vessels were attenuated in ablated noise-exposed mice, while microglial activation and abundance in the brain was greatly increased. Expression of phagocytic NADPH oxidase (NOX-2) and vascular cell adhesion molecule-1 (VCAM-1) mRNA in the aorta was reduced, while NFκB signaling appeared to be activated in the brain upon ablation. In sum, we show dissociation of cerebral and peripheral inflammatory reactions in response to aircraft noise after LysM+ cell ablation, wherein peripheral myeloid inflammatory cells represent a dominant part of the pathomechanism for noise stress-induced cardiovascular effects and their central nervous counterparts, microglia, as key mediators in stress responses.

[State of local immunity in herpetic stomatitis patients].

It was set by us, that at intensifying of herpetic stomatititis of mucous membrane of oral cavity for patients the deficit of lysozyme and antibodies of class is marked A in the mixed saliva. At what the degree of expressed of the exposed violations of local immunity correlated with frequency of relapses of viral infection and its duration.

Intestinal lysozyme releases Nod2 ligand(s) to promote the intestinal mucosal adjuvant activity of cholera toxin.

Commensal bacteria boost serum IgG production in response to oral immunization with antigen and cholera toxin (CT) in a manner that depends on Nod2 (nucleotide-binding oligomerization domain-containing protein 2). In this study, we examined the role of intestinal lysozyme (Lyz1) in adjuvant activity of CT. We found that Lyz1 released Nod2 ligand(s) from bacteria. Lyz1 deficiency reduced the level of circulating Nod2 ligand in mice. Lyz1 deficiency also reduced the production of IgG and T-cellspecific cytokines after oral immunization in mice. Supplementing Lyz1-deficient mice with MDP restored IgG production. Furthermore, overexpression of Lyz1 in intestinal epithelium boosted the antigen-specific IgG response induced by CT. Collectively, our results indicate that Lyz1 plays an important role in mediating the immune regulatory effect of commensal bacteria through the release of Nod2 ligand(s).

LYG1 Deficiency Attenuates the Severity of Acute Graft-Versus-Host Disease via Skewing Allogeneic T Cells Polarization Towards Treg Cells.

Acute graft-versus-host disease (aGVHD) is a lethal complication after allogeneic hematopoietic stem cell transplantation. The mechanism involves the recognition of host antigens by donor-derived T cells which induces augmented response of alloreactive T cells. In this study, we characterized the role of a previously identified novel classical secretory protein with antitumor function-LYG1 (Lysozyme G-like 1), in aGVHD. LYG1 deficiency reduced the activation of CD4+ T cells and Th1 ratio, but increased Treg ratio in vitro by MLR assay. By using major MHC mismatched aGVHD model, LYG1 deficiency in donor T cells or CD4+ T cells attenuated aGVHD severity, inhibited CD4+ T cells activation and IFN-γ expression, promoted FoxP3 expression, suppressed CXCL9 and CXCL10 expression, restrained allogeneic CD4+ T cells infiltrating in target organs. The function of LYG1 in aGVHD was also confirmed using haploidentical transplant model. Furthermore, administration of recombinant human LYG1 protein intraperitoneally aggravated aGVHD by promoting IFN-γ production and inhibiting FoxP3 expression. The effect of rhLYG1 could partially be abrogated with the absence of IFN-γ. Furthermore, LYG1 deficiency in donor T cells preserved graft-versus-tumor response. In summary, our results indicate LYG1 regulates aGVHD by the alloreactivity of CD4+ T cells and the balance of Th1 and Treg differentiation of allogeneic CD4+ T cells, targeting LYG1 maybe a novel therapeutic strategy for preventing aGVHD.

Lysozyme M deficiency leads to an increased susceptibility to Streptococcus pneumoniae-induced otitis media.

BACKGROUND: Lysozyme is an antimicrobial innate immune molecule degrading peptidoglycan of the bacterial cell wall. Lysozyme shows the ubiquitous expression in wide varieties of species and tissues including the tubotympanum of mammals. We aim to investigate the effects of lysozyme depletion on pneumococcal clearance from the middle ear cavity. METHODS: Immunohistochemistry was performed to localize lysozyme in the Eustachian tube. Lysozyme expression was compared between the wild type and the lysozyme M-/- mice using real time quantitative RT-PCR and western blotting. Muramidase activity and bactericidal activity of lysozyme was measured using a lysoplate radial diffusion assay and a liquid broth assay, respectively. To determine if depletion of lysozyme M increases a susceptibility to pneumococal otitis media, 50 CFU of S. pneumoniae 6B were transtympanically inoculated to the middle ear and viable bacteria were counted at day 3 and 7 with clinical grading of middle ear inflammation. RESULTS: Immunolabeling revealed that localization of lysozyme M and lysozyme P is specific to some/particular cell types of the Eustachian tube. Lysozyme P of lysozyme M-/- mice was mainly expressed in the submucosal gland but not in the tubal epithelium. Although lysozyme M-/- mice showed compensatory up-regulation of lysozyme P, lysozyme M depletion resulted in a decrease in both muramidase and antimicrobial activities. Deficiency in lysozyme M led to an increased susceptibility to middle ear infection with S. pneumoniae 6B and resulted in severe middle ear inflammation, compared to wild type mice. CONCLUSION: The results suggest that lysozyme M plays an important role in protecting the middle ear from invading pathogens, particularly in the early phase. We suggest a possibility of the exogenous lysozyme as an adjuvant therapeutic agent for otitis media, but further studies are necessary.

Decreased clearance of Pseudomonas aeruginosa from airways of mice deficient in lysozyme M.

Lysozyme is a ubiquitous and abundant, cationic, antimicrobial polypeptide of leukocytes and epithelia, but its biological function in host defense is largely unexplored. To ascertain the role of lysozyme during bacterial infection of murine airways, we exposed the airways of lysozyme M-deficient (lys M-/-) mice to the pulmonary pathogen Pseudomonas aeruginosa and examined the host's response to infection. Despite partial compensation as a result of the appearance of lysozyme P in the infected airways of lys M-/- mice, these lys M-/- mice showed decreased clearance of P. aeruginosa compared with their lys M+/- or lys M+/+ littermates. Lysozyme contributes to optimal clearance of P. aeruginosa from the murine airways.

Immune status during fracture of lower jaw.

Immune status during fracture of lower jaw is a very important factor of pathogenesis. Immune depression is developing shortly after the trauma and it turns out to be a bad prognostic sign, during which the risk of developing the bone wound complications and traumatic osteomyelitis increase, and in case of absence of such complications we are faced with significant extension of a term of healing of bone wounds. We have carried out immune studies in 20 patients with lower jaw fractures. To study SlgA and lysozyme activity we took saliva and studied percentage of T- and B-lymphocytes (and their sub-populations) in blood by the use of micro method. Immunoglobulins were defined by the method of radial immuno diffusion; we determined the interferon system by in vitro stimulation of leucocytes; neutrophilic phagocyte activity was studied by the method of Kost U.A. and Stepko M.I. According to the obtained results, during fractures of lower jaw sharp decrease of interferon system and significant decrease of phagocyte activity was observed. Likewise was decreased lysozyme and SlgA indices, which refer to the depression of immune status of mouth cavity. From the cell immunity indices the decrease of T-activators and T-helpers and reduction of immunoregulation index should be emphasized. Quantity of B-lymphocytes was decreased by 10%. With the practical point of view the obtained results refer, alongside with carrying out the surgical, orthopedic and anti-microbial treatments, to the urgency of application of activators of phagocytosis, interferon and lysozyme immunomodulators. With the view of correction of cell immunity it is necessary to correct factors of T-lymphocytes and to increase activity of SigA and lysozyme, as the factors determining local resistance. The results obtained by us are rather important with the view of both immunology and applied, practical medicine. It enables us to lead the substantiated immune therapy, which will be harmonized with other etiotropic anti microbial therapy and will help us to improve significantly the results of anti-inflammation therapy and to decrease cases of purulent complications.

Composition of cartilage from lysozyme-deficient rabbits.

Costal and auricular cartilage obtained from mutant rabbits exhibiting lysozyme deficiency has been found to be identical to similar tissue from control animals in a variety of biochemical parameters. These data seriously question the putative role of lysozyme as a structural component of cartilage.

The role in flagellar rod assembly of the N-terminal domain of Salmonella FlgJ, a flagellum-specific muramidase.

The C-terminal half of the Salmonella flagellar protein FlgJ has peptidoglycan hydrolyzing activity and it has been suggested that it is a flagellum-specific muramidase which locally digests the peptidoglycan layer to permit assembly of the rod structure to proceed through the periplasmic space. It was also suggested that FlgJ might be involved in rod formation itself, although there was no direct evidence for this. We purified basal body structures from SJW1437(flgJ) transformed with plasmids encoding various mutant FlgJ proteins and found that these basal bodies possessed the periplasmic P ring but lacked the outer membrane L ring; they also lacked a hook at their distal end. All of these mutant FlgJ proteins had an altered or missing C-terminal domain but had at least the first 151 amino acid residues of the N-terminal domain. Immunoblotting analysis of fractionated cell extracts revealed that a rod/hook export class protein, FlgD, was exported to the periplasm but not to the culture supernatant in these mutants. FlgJ was shown to physically interact with several proteins, and especially FliE and FlgB, which are believed to reside at the cell-proximal end of the rod. On the basis of these results, we conclude that the N-terminal 151 amino acid residues of FlgJ are directly involved in rod formation and that the muramidase activity of FlgJ, though needed for formation of the L ring and subsequent events such as hook formation, is not essential for rod or P ring formation. In contrast, muramidase activity alone does not support rod assembly.

Comparison of the microbicidal and muramidase activities of mouse lysozyme M and P.

Lysozyme is one of the most abundant antimicrobial proteins in the airspaces of the lung. Mice express two lysozyme genes, lysozyme M and P, but only the M enzyme is detected in abundance in lung tissues. Disruption of the lysozyme M locus significantly increased bacterial burden and mortality following intratracheal infection with a Gram-negative bacterium. Unexpectedly, significant lysozyme enzyme activity (muramidase activity) was detected in the airspaces of uninfected lysozyme M-/- mice, amounting to 25% of the activity in wild-type mice. Muramidase activity in lysozyme M-/- mice was associated with increased lysozyme P mRNA and protein in lung tissue and bronchoalveolar lavage fluid respectively. The muramidase activity of recombinant lysozyme P was less than that of recombinant M lysozyme. Recombinant P lysozyme was also less effective in killing selected Gram-negative bacteria, requiring higher concentrations than lysozyme M to achieve the same level of killing. The lower antimicrobial activity of P lysozyme, coupled with incomplete compensation by P lysozyme in lysozyme M-/- mice, probably accounts for the increased susceptibility of null mice to infection. Recombinant lysozyme M and P were equally effective in killing selected Gram-positive organisms. This outcome suggests that disruption of both M and P loci would significantly increase susceptibility to airway infections, particularly those associated with colonization by Gram-positive organisms.

Escherichia coli detection by GFP-labeled lysozyme-inactivated T4 bacteriophage.

Escherichia coli has been used as an indicator of the fecal contamination of water and food, identifying potential health hazards. In this study, an E. coli-specific bacteriophage, T4, was used to detect E. coli bacteria. The T4 phage small outer capsid (SOC) protein was used to present green fluorescent protein (GFP), an easily detectable marker protein, on the phage capsid. To inactivate phage lytic activity, we used the T4e(-) phage, which does not produce the lysozyme responsible for host cell lysis. Infection of E. coli K12 cells with the GFP-labeled T4e(-) phage (T4e(-)/GFP) enabled the visualization and distinction of E. coli K12 cells from T4 phage-insensitive cells, Pseudomonas aeruginosa. Prolonged incubation of E. coli K12 cells with the T4e(-)/GFP phage did not lead to cell lysis. Propagation of T4e(-)/GFP in host cells increased the intensity of green fluorescence, making the distinction of E. coli cells from other cells simple and effective. This method enables the rapid, conclusive quantitation of E. coli cells within an hour.

[Lysozyme activity in the saliva of industrial workers exposed to fluorine compounds]. / Badania aktywnosci lizozymu w slinie pracowników przemyslu narazonych na dzialanie zwiazków fluoru.

The authors performed investigations in Phosphoric Fertilizers Works in Gdansk to find out whether or not the work environment contaminated by fluorine compounds affects the activity of lysozome--the protective enzyme of saliva. In some in vitro experiments lysozome activity in exposed workers' saliva was found to be significantly lowered, as opposed to that in unexposed workers. In vivo experiments did not indicate any effects of work conditions on the activity of this enzyme. The obtained results, in vivo and in vitro, do not demonstrate any clear effects of work environment in the Phosphoric Fertilizers Works in Gdansk, upon lysozome activity in workers' saliva.

[Lysozyme in atopic dermatitis]. / Lizozym w atopowym zapaleniu skóry.

The aim of the present study was to determine the levels of lysozyme in serum and saliva in 10 patients with atopic dermatitis (AD). A significantly decreased lysozyme levels in saliva compared to controls (p less than 0.01) were showed, whereas no differences were found in lysozyme activity in serum of patients and controls. The reduced levels in saliva can hardly be explained. The decreased levels of lysozyme in external fluids may be one explanation for the well-known predisposition for AD patients to an increased susceptibility to many cutaneous infections.

[Lysozyme level and rheological properties of the sputum in patients with chronic bronchitis]. / Soderzhanie lizotsima i reologicheskie svoistva mokroty u bol'nykh khronicheskim bronkhitom.

The authors presented some data on the lysozyme content and adhesion features of the sputum in 31 patients: 19 patients with chronic obstructive bronchitis and 12 patients with chronic bronchitis against a background of bronchial asthma. Marked reverse correlation between the lysozyme content and sputum adhesion values (r = -0.79) was found. With the subsiding of exacerbation and remission occurrence the lysozyme content increased and a sputum adhesion value reduced. In the exacerbation phase the mean lysozyme content in the sputum was 3.6 +/- 0.1 mg/mg of protein, and in remission occurrence 6.9 +/- 0.2 mg/mg of protein. The adhesion value was 0.6 X 10(4) +/- 0.22 X 10(4) N/m2 and 0.32 X 10(4) +/- 0.01 X 10(4) N/m2, respectively. The time course of the lisozyme content in the sputum of patients with chronic bronchitis can be used as a prognostic factor to assess remission occurrence rates and the nature of change of rheological features of the sputum.

[Factors of protracted and recurrent course of chronic erosions of the stomach]. / Faktory zatiazhnogo i retsidiviruiushchego techeniia u bol'nykh s khronicheskimi éroziiami zheludka.

A study was made of the disease pathogenesis in 58 patients with recurrent chronic erosions of the gastric mucosa. It has been established that an important role in the relapses of the pathological process is played by pathological microflora, disturbances in humoral immunity and local microcirculation, and long existence of the zone of fibrinoid necrosis.

[Humoral nonspecific immunity in patients with post-burn cicatrical strictures of the esophagus]. / Gumoral'naia nespetsificheskaia zashchita u bol'nykh s posleozhogovoi rubtsovoi strikturoi pishchevoda.

The authors have studied the significance of factors of the humoral non-specific defense (HND) in 37 patients with cicatricial constrictions of the oesophagus and stomach. The data obtained were used for choosing the optimum terms for gastrostoma and oesophagoplasty. In 14 patients treatment with lysozyme was performed due to decreased indices of HND.

[Indicators of nonspecific resistance of the body of patients with stomach cancer subjected to different methods of preoperative care]. / Pokazateli nespetsificheskoi rezistentnosti organizma u bol'nykh rakom zheludka pri raznoi metodike predoperatsionnoi podgotovki.

An analysis of observation of 102 patients with gastric cancer has shown the application of anabolic steroid drugs in combination with plastic and energetic substrates, vitamins and biostimulators to result in increased indices of non-specific resistance in the preoperative period. The operative trauma against this background results in considerably less depression of resistance mechanisms than in the group of patients with the traditional preoperative management. It is followed by a less amount of early complications and lethality after operation.

Characterization of expression, activity and role in antibacterial immunity of Anopheles gambiae lysozyme c-1.

There are eight lysozyme genes in the Anopheles gambiae genome. Transcripts of one of these genes, LYSC-1, increased in Anopheles gambiae cell line 4a3B by 24 h after exposure to heat-killed Micrococcus luteus. Lysozyme activity was also identified in conditioned media from the cell line from which the protein was purified to homogeneity using ion exchange and gel filtration. Mass spectrometric analysis of the purified protein showed 100% identity to lysozyme c-1. Purified lysozyme c-1 was tested against non-mosquito-derived as well as culturable bacteria isolated from mosquito midguts. Lysozyme c-1 had negligible effects on the growth of most mosquito-derived bacteria in vitro but did inhibit the growth of M. luteus. Although Lys c-1 did not directly kill most bacteria, knockdown of LYSC-1 resulted in significant mortality in mosquitoes subjected to hemocoelic infections with Escherichia coli but not M. luteus thus suggesting that this protein plays an important role in antibacterial defense against selected bacteria.