NADase as a target molecule of in vivo suppression of the toxicity in the invasive M-1 group A Streptococcal isolates

<p>Abstract</p> <p>Background</p> <p>NAD-glycohydrolase (NADase) secreted by M-1 group A streptococcal (GAS) isolates are suspected as one of the virulence factors to cause severe invasive disease including streptococcal toxic shock-like syndrome (STSS). M-1 GAS strains were divided into three groups based on NADase activity: high activity, low activity and no activity in our previous report.</p> <p>Results</p> <p>The representative high activity isolates taken from STSS patients showed higher virulence compared with isolates from the low activity group, when used to infect mice. The knockout mutant of the <it>nga </it>gene, which encodes NADase also showed reduced virulence in a mouse infection study. The cloned <it>nga </it>gene was able to significantly complement the lost virulence. In addition, the solution containing purified recombinant IFS, which is an inhibitor of NADase, partially rescued mice infected with <it>S. pyogenes</it>.</p> <p>Conclusions</p> <p>These results indicate that NADase is important for the virulence of <it>S. pyogenes </it>in vivo and is the potential target to suppress the virulence.</p

Pulmonary resection for metachronous metastatic gastric cancer diagnosed using multi-detector computed tomography: Report of five cases

Introduction As pulmonary resection for metastatic gastric cancer has been rarely reported on, the role of metastasectomy remains unclear in such settings. We reviewed the clinicopathological characteristics and surgical outcomes of patients with metachronous pulmonary metastasis from gastric cancer (MPMGC) diagnosed using multi-detector computed tomography (MDCT) who underwent pulmonary resection. Presentation of case From September 2002 to May 2018, five patients underwent pulmonary resection for MPMGC at Shizuoka Cancer Center. All patients received curative resection for initial gastric cancer. Three patients received adjuvant chemotherapy. The median age at pulmonary resection was 70 years. The median disease-free interval between initial gastrectomy and MPMGC diagnosis was 41 months. The first site of recurrence was the lung in all patients. All patients were diagnosed as having primary lung cancer using MDCT before pulmonary resection and fit the surgical indication for primary lung cancer. Lobectomy was performed in three patients, while wedge resection was performed in two. The median overall survival following pulmonary resection was 79 (range, 18–89) months. Two patients experienced recurrence. While one showed recurrence in the mediastinal lymph node, in the other it was observed in the remnant lung; the latter underwent repeated pulmonary resection followed by systemic chemotherapy. Four patients survived for longer than 4 years after pulmonary resection. Conclusions Of the five patients with MPMGC diagnosed using MDCT who underwent pulmonary resection, long-term survival was achieved after pulmonary resection in four. Thus, pulmonary resection may be considered for those diagnosed with lung nodules after surgery for gastric cancer, and who fit the surgical indication for primary lung cancer

Relevance of the two-component sensor protein CiaH to acid and oxidative stress responses in Streptococcus pyogenes

BACKGROUND: The production of virulence proteins depends on environmental factors, and two-component regulatory systems are involved in sensing these factors. We previously established knockout strains in all suspected two-component regulatory sensor proteins of the emm1 clinical strain of S. pyogenes and examined their relevance to acid stimuli in a natural atmosphere. In the present study, their relevance to acid stimuli was re-examined in an atmosphere containing 5% CO(2). RESULTS: The spy1236 (which is identical to ciaH(py)) sensor knockout strain showed significant growth reduction compared with the parental strain in broth at pH 6.0, suggesting that the Spy1236 (CiaH(py)) two-component sensor protein is involved in acid response of S. pyogenes. CiaH is also conserved in Streptococcus pneumoniae, and it has been reported that deletion of the gene for its cognate response regulator (ciaR(pn)) made the pneumococcal strains more sensitive to oxidative stress. In this report, we show that the spy1236 knockout mutant of S. pyogenes is more sensitive to oxidative stress than the parental strain. CONCLUSIONS: These results suggest that the two-component sensor protein CiaH is involved in stress responses in S. pyogenes

Clindamycin-Induced CovS-Mediated Regulation of the Production of Virulent Exoproteins Streptolysin O, NAD Glycohydrolase, and Streptokinase in Streptococcus pyogenes▿

The administration of high-dose clindamycin (CLI) along with penicillin is recommended for the treatment of streptococcal toxic shock syndrome. However, the prevalence of CLI-resistant Streptococcus pyogenes strains is increasing worldwide, and the effect of CLI on CLI-resistant S. pyogenes strains remains unknown. We aimed to evaluate the effect of CLI on the in vitro production of three major virulent exoproteins, namely, streptolysin O (Slo), NAD glycohydrolase (Nga), and streptokinase (Ska), by CLI-resistant S. pyogenes strains. After the incubation of M1 serotype CLI-resistant S. pyogenes D2TY in the presence of 1 μg/ml CLI, the amounts of Slo, Nga, and Ska and the levels of slo, nga, and ska mRNA in the supernatant were analyzed by Northern blotting and Western blotting, respectively. The results of both assays showed that the production of Slo, Nga, and Ska was higher with CLI treatment than without CLI treatment. We evaluated the role of the sensor kinase CovS, which is involved in the two-component system of S. pyogenes, in the CLI-induced production of these three exoproteins. Northern blotting analysis revealed that CLI induced the expression of covS mRNA in wild-type strain D2TY. Furthermore, both Northern blotting and Western blotting analyses showed that CLI decreased the levels of expression of Slo, Nga, and Ska in isogenic covS mutant D2TYcovS. These results suggest that CLI increases the production of three virulent exoproteins in CLI-resistant S. pyogenes strains via the action of CovS

Alteration of endogenous corticosteroids and catecholamines in allergen-induced eosinophilic inflammation in Brown Norway rats

Although various types of stress activate a pituitary adrenal response, the alteration of endogenous corticosteroids and catecholamines during asthma remains unclear. The aim of this study was to assess changes in endogenous corticosteroid and catecholamine levels in allergic eosinophilic inflammation in rats, using metabolic cages. Brown Norway rats (female, 6 weeks old) were sensitized with intraperitoneal injections of ovalbumin on days 0 and 2 and challenged with either an aerosol of ovalbumin or saline for 30 min on day 21. Levels of urinary 11- hydroxycorticosteroid (OHCS), a primary metabolite of corticosterone; epinephrine and norepinephrine were determined in pooled samples taken 0–24 h before and 8–32 h after the challenge. Serum adrenocorticotropic hormone, corticosterone levels and cell counts in bronchoalveolar lavage fluid were assessed 32–36 h after the challenge, as well as lung eosinophil peroxidase activity, an indirect index of eosinophil infiltration. The numbers of total cells and eosinophils in bronchoalveolar lavage fluid and lung eosinophil peroxidase activity were significantly increased in the ovalbumin-challenged rats compared with the saline-challenged rats. While urinary OHCS and serum corticosterone levels were significantly increased after challenge in the ovalbumin-challenged rats, compared with the saline-challenged rats (2.1 ± 0.1 ×10−1 vs 1.7 ± 0.1 x 10−1 mg/g creatinine, P < 0.05 and 482 ± 49 vs 348 ± 19 ng/mL, P < 0.02, respectively), serum adrenocorticotropic hormone levels did not differ between the two groups. Urinary epinephrine and norepinephrine excretion also did not differ between the two groups. It is concluded that endogenous corticosterone, but not catecholamine, increases as a pathophysiologic adrenal response, possibly to protect lung during allergic eosinophilic inflammation

Induction of systemic and mucosal antibody responses in mice immunized intranasally with aluminium-non-adsorbed diphtheria toxoid together with recombinant cholera toxin B subunit as an adjuvant. Vaccine 18:743–751

Abstract Nasal mucosal immunization is very attractive for vaccination to prevent various bacterial and viral infectious diseases because of induction of systemic and mucosal immune responses. The aim of the present study was to investigate the possibility of changing the immunization procedure of diphtheria toxoid (DT) from intramuscular or subcutaneous injection to intranasal administration. Intranasal immunization with aluminium-non-adsorbed diphtheria toxoid (nDT) together with recombinant cholera toxin B subunit (rCTB, 10 mg) induced, at a concentration of 5 Lf, high levels of serum DT-speci®c IgG antibody responses and high or moderate levels of the speci®c IgA antibody responses in all mice and only a slight level of the speci®c IgE antibody responses in some mice. Furthermore, suciently high diphtheria antitoxin titres more than 0.1 international units (IU) ml À1 were obtained from mice which showed high levels of serum DT-speci®c IgG antibody responses. Under the same experimental conditions, induction of signi®cant levels of mucosal DT-speci®c IgA antibody responses occurred in the nasal cavity, the lung, the saliva and vaginal secretions and the small and large intestines of all mice, although there were dierent titres between individual mice. Similar results were also obtained with rCTB-speci®c serum IgG and IgA and mucosal IgA antibody responses; serum rCTB-speci®c IgE antibody titres were not detected. These results show that intranasal administration of nDT with rCTB must be a very useful means for vaccination against diphtheria.

Small Amino Acid Changes in the V3 Loop of Human Immunodeficiency Virus Type 2 Determines the Coreceptor Usage for CXCR4 and CCR5

AbstractHIV-2 GH-1 is a molecular clone derived from an AIDS patient from Ghana. In contrast to the prototypic molecular clone ROD, GH-1 exhibits a narrow range of target cell specificity. By an infectious assay using HeLa-CD4 cells stably transfected with an HIV-1 LTR-β-galactosidase reporter gene and transiently expressing various cloned chemokine receptors, we have examined the coreceptor usage of GH-1. In contrast to ROD, which uses principally CXCR4, GH-1 was found to use mainly if not exclusively CCR5 but not CXCR4. The distinct coreceptor usage of these two molecular clones allowed us to further map the region of gp120 that is important for the coreceptor specificity. By constructing a series of chimeric viruses between GH-1 and ROD, we have demonstrated that the C-terminal half of the V3 loop region of gp120 determines the differential coreceptor usage between GH-1 and ROD, and only a few amino acid differences in this region appear to be able to shift the specificity between CCR5 and CXCR4. Notably, the shift in the coreceptor usage from CCR5 to CXCR4 is associated with an increase in the net positive charge in the V3 region