Enhancement of interleukin-8-induced chemotactic response and reactive oxygen species production in HL-60 cells expressing CXCR1.

Neutrophils play a pivotal role in immunity against infection by ingesting and killing invading microbes. Neutrophils isolated from human peripheral blood have been used for a number of studies conducted for evaluation of immunomodulating drugs, cytokines, and microbe products. Human promyelocytic leukemia cells, HL-60, have been extensively studied because they can differentiate into neutrophil-like cells by addition of all-trans retinoic acid or dimethyl sulfoxide. For a system that would always allow experimental use of granulocytic cells in a uniformly activated state, we have established HL-60 cell lines with increased migratory activity by transducing the CXC chemokine receptor 1 (CXCR1) gene. When these cell lines were primed with CXC chemokine ligand 8 (IL-8), a slight increase in reactive oxygen species production induced by phorbol myristate acetate (PMA) or zymosan A stimuli was observed. A significance increase in migratory activity was noticed when the HL-60 cells transduced CXCR1 were stimulated with IL-8 in the Boyden chamber method. The gene-transduced HL-60 cell lines may be used as a substitute for neutrophils in screening the effects of various immunomodulating drugs on the migratory activity induced by IL-8.

Suppression of phosphorylation of extracellular-signal-regulated kinase and p38 mitogen-activated protein kinase in polymorphonuclear leukocytes by the proton pump inhibitor lansoprazole.

Lansoprazole (LPZ) is a proton pump inhibitor that suppresses gastric secretion and exerts anti-inflammatory effects on immune cells. Recently, LPZ has been used for the treatment of peptic ulcer and gastritis, which can be caused by Helicobacter pylori, due to its potent acid-suppressive effects. We focused the aim to the anti-inflammatory effects on the over-activation of neutrophils, and investigated the effects of LPZ on the signal transduction of the mitogen-activated protein kinase (MAPK) family. LPZ slightly phosphorylated p38 MAPK of neutrophils at a concentration of 10 microg/ml , but did not phosphorylate extracellular-signal regulated kinase (ERK) 1/2. Pretreatment of neutrophils with (1-5 microg/ml ) LPZ strongly attenuated the phorbol-12-myristate-13-acetate-stimulated phosphorylation of ERK1/2, and LPZ slightly suppressed the lipopolysaccharide (LPS)- and N-formylmethionylleucylphenylalanine-stimulated phosphorylation of p38. ERK1/2 produces the mitochondrial anti-apoptotic proteins, and the signaling pathway from LPS and N-formylmethionylleucylphenylalanine to p38 is the main pathway for reactive oxygen species production. The mechanism of anti-inflammatory effect of LPZ on hyper-activated neutrophils is suggested to be the suppression of signal transduction of ERK1/2 and p38 MAPK.

Influences of aflatoxin B1 on reactive oxygen species generation and chemotaxis of human polymorphonuclear leukocytes.

The effects of aflatoxin (AF), a hepatotoxic agent and the strongest carcinogen in nature, on polymorphonuclear leukocyte (PMN) chemotaxis and chemiluminescence (CL) were studied. Luminol-dependent CL activity, which reflects the production of reactive oxygen species (ROS) from PMNs, was up-regulated to approximately 150% when PMNs were treated with 0.05 ng/ml of AFB1 upon stimulation with N-formyl-methionine-leucine-phenylalanine (fMLP) or zymosan. On the other hand, PMN CL activity was down-regulated to approximately 25% of the control when PMNs were treated with 50 ng/ml of AFB1 upon stimulation with zymosan. The effect of AFB1 on PMN chemotaxis was also investigated using the Boyden chamber method. The chemotactic ability of PMNs when interleukin (IL)-8 was used as a chemoattractant was inhibited in a dose-dependent manner at AFB1 concentrations of >10 ng/ml. In reverse transcriptase (RT)-PCR analysis, gene expression levels of CXC chemokine receptor (CXCR)1/2, whose ligands are IL-8, granulocyte chemotactic protein (GCP)-2, neutrophil attractant-activation protein (NAP)-2, and epithelial neutrophil-activating protein (ENA)-78, which regulate PMN chemotaxis, were also down-regulated in a dose-dependent manner by 50 ng/ml AFB1. mRNA expression levels of CXCR1/2 were down-regulated to approximately 85% of that in the controls when PMNs were treated with 100 ng/ml AFB1. These results suggest that a high concentration of AFB1 reduces the chemotactic ability of PMNs via the CXCR1/2 cascade indirectly.

[Transferability of vanA gene from vancomycin-resistant Enterococcus faecalis in the digestive tract of specific pathogen-free mice].

We evaluated the transferability of vanA gene from vancomycin-resistant Enterococcus faecalis (VREF) to vancomycin-sensitive E. faecalis (VSEF) in vitro and in vivo. In vitro conjugal transfer experiment by filter mating, the vanA gene of VREF was transferable at the high frequency to VSEF and a mutant strain which cured vanA gene of VREF. In vivo studies in the digestive tract of specific pathogen-free mice pretreated with oral antibiotics, transconjugants were also detected from the feces of a mouse at the lower frequency. However, the colonization of transconjugants was transient. The vanA gene in the donor and the transconjugant strain was confirmed by using a polymerase chain reaction method. These results suggest that VSEF colonizing in the human digestive tract might be developed to VREF by transferring of the vanA gene.

Evaluation of TREM1 gene expression in circulating polymorphonuclear leukocytes and its inverse correlation with the severity of pathophysiological conditions in patients with acute bacterial infections.

During bacterial infection, activated polymorphonuclear leukocytes (PMNs) often cause inflammation and organ dysfunction in severely ill patients. Gene expression was analyzed in circulating PMNs isolated from these patients to determine the distinct expression profile. We focused on immunomodulatory genes, such as those for pattern recognition receptors, inflammatory cytokines, PMN surface antigens, and myeloid cell receptors in PMNs. Gene expression in 23 patients (12 with pneumonia and 11 with sepsis) were analyzed using quantitative real-time polymerase chain reaction. The mRNA levels of TLR2 (20/23 cases) and CD14 (18/23 cases) were upregulated in the PMNs of patients when compared with healthy subjects. The mRNA expression levels of TLR4 (16/23 cases) and IL6 (16/23 cases) were downregulated in patients' PMNs, and of TNFA (16/23 cases) were upregulated in these cells. Although mRNA levels of IL8RA (15/23 cases) were downregulated in PMNs, MAC-1 mRNA levels (14/23 cases) were upregulated in the same cells. Copies of the TREM1 transcript were 0.7- to 2.1-fold higher in patients with moderate pneumonia than in the healthy subjects; the average fold change was 1.1. The mRNA levels were 0.3-fold lower in the patients with severe pneumonia and sepsis than in the healthy subjects. In conclusion, the downregulation of TREM1 expression in PMNs is associated with the severity of the pathophysiological conditions and may be used as a surrogate marker of acute bacterial infections.

[Effect of oral administration of ß-D-glucan from Aureobasidium pullulans ADK-34 on Candida and MRSA infections in immunosuppressed mice].

UNLABELLED: We examined the effect of the oral administration of ß-D-glucan derived from Aureobasidium pullulans ADK-34 (AP-FBG) on Candida albicans or methicillin-resistant Staphylococcus aureus (MRSA) infection in immunosuppressed mice. Mice pretreated with cyclophosphamide (CY) were intraperitoneally administered AP-FBG for 4 days and then infected with 6×10(4) C. albicans cells. In a preliminary experiment, the survival time of the Candida-infected mice treated with AP-FBG was clearly prolonged. Similarly, the effect of the oral administration of AP-FBG was examined. Mice were orally given 2.5% AP-FBG in feed for 42 days from 14 days prior to 2×10(4) C. albicans cells infection. The survival time of mice treated with AP-FBG was significantly prolonged and the viable cell count in the kidneys of the survivors was significantly decreased at 30 days after infection. The effects of the oral administration of AP-FBG on intestinal MRSA infection were also examined. Mice were given 2.5% AP-FBG orally in feed for 30 days before and after oral MRSA infection and treated with CY 12 days after the infection. The number of viable MRSA cells or the IgA production in feces did not significantly change, while AP-FBG administration seemed to relieve temporally the loss of body weight of mice. CONCLUSIONS: These results suggest that oral pre-administration of AP-FBG promoted resistance of CY-treated mice to C. albicans and lessened the weight reduction of CY-mice infected by MRSA.

Recurrent Helicobacter cinaedi cellulitis and bacteremia in a patient with systemic lupus erythematosus.

A 31-year-old woman who had developed systemic lupus erythematosus at 17 years of age was admitted to the hospital for suspected cellulitis in the lower extremities. A blood culture performed upon admission to the hospital detected Helicobacter cinaedi (H. cinaedi), which was also isolated in blood and fecal cultures obtained on the 42nd hospital day. Bacterial translocation of H. cinaedi present in the intestines may have led to the development of recurrent bacteremia and cellulitis. In cases such as this, appropriate antibiotics therapy might be needed for more than one month. Moreover, H. cinaedi, a cause of emerging infections, requires a long period of time to grow; therefore it is important to extend the culture duration when the presence of this bacterium is suspected.

A D-octapeptide drug efflux pump inhibitor acts synergistically with azoles in a murine oral candidiasis infection model.

Clinical management of patients undergoing treatment of oropharyngeal candidiasis with azole antifungals can be impaired by azole resistance. High-level azole resistance is often caused by the overexpression of Candida albicans efflux pump Cdr1p. Inhibition of this pump therefore represents a target for combination therapies that reverse azole resistance. We assessed the therapeutic potential of the D-octapeptide derivative RC21v3, a Cdr1p inhibitor, in the treatment of murine oral candidiasis caused by either the azole-resistant C. albicans clinical isolate MML611 or its azole-susceptible parental strain MML610. RC21v3, fluconazole (FLC), or a combination of both drugs were administered orally to immunosuppressed ICR mice at 3, 24, and 27 h after oral inoculation with C. albicans. FLC protected the mice inoculated with MML610 from oral candidiasis, but was only partially effective in MML611-infected mice. The co-application of RC21v3 (0.02 µmol per dose) potentiated the therapeutic performance of FLC for mice infected with either strain. It caused a statistically significant decrease in C. albicans cfu isolated from the oral cavity of the infected mice and reduced oral lesions. RC21v3 also enhanced the therapeutic activity of itraconazole against MML611 infection. These results indicate that RC21v3 in combination with azoles has potential as a therapy against azole-resistant oral candidiasis.

Efficacy of intravenous itraconazole against invasive pulmonary aspergillosis in neutropenic mice.

The efficacy of itraconazole (ITZ) solubilized in hydroxypropyl-beta-cyclodextrin (ITZ-IV) was examined in a murine model of invasive pulmonary aspergillosis (IPA). Immunosuppressed mice were infected by the intratracheal inoculation of Aspergillus fumigatus conidia (2 x 10(6) conidia/mouse). Their body weight rapidly decreased and they died within 6 days after infection. Intravenous administration of various doses of ITZ-IV was started 24 h after infection and was continued once a day for 4 days. ITZ-IV at daily doses of 10, 20, or 40 mg/kg was as effective as the intraperitoneal administration of amphotericin B (AMPH) at a dosage of 1 mg/kg daily in improving survival. ITZ-IV (20 mg/kg per day), as well as AMPH (1 mg/kg per day) significantly lowered the fungal burden in the pulmonary tissues. Histological improvement was seen within 2 days after the beginning of administration of ITZ-IV (20 mg/kg per day). In mice intravenously given a single dose of ITZ-IV (20 mg/kg), the blood level and pulmonary tissue level of ITZ plus its active metabolites, mainly hydroxyitraconazole (OH-ITZ), decreased gradually after the injection, but after 4 h their concentration was still between 1.4 microg/ml (ITZ) and 1.9 microg/ml (OH-ITZ), concentrations that were approximately 10 to 20 times greater than the minimum inhibitory concentration (MIC) of ITZ for challenging the strain of A. fumigatus (0.16 microg/ml). These results support the clinical usefulness of ITZ-IV for the treatment of IPA in immunocompromised patients.

Protection of mice from lethal endogenous Candida albicans infection by immunization with Candida membrane antigen.

The protective effects of immunization with Candida membrane antigen (CMA) on a systemic infection originating from intestinally colonized Candida albicans were examined. The colonization of orally inoculated C. albicans in the intestinal tract was established in BALB/c mice that had been concomitantly treated with oral doses of antibacterial drugs. In these animals, a systemic dissemination of C. albicans with fatal outcome was induced by a repeated dosing of prednisolone. In this endogenous infection model, the effects of immunization by CMA on the infection were examined. CMA-immunized mice showed a longer lifespan than unimmunized mice. The protective effect of CMA immunization in immunosuppressed mice was also measured by a decrease in body weight loss after treatment with prednisolone and in the number of viable Candida cells in the target organs, the kidneys and livers. However, the CFU of C. albicans in the intestinal tract was not significantly lowered. These results suggest that CMA immunization inhibited the dissemination of systemic Candida infection from the intestinal tract induced by treatment with prednisolone.

Opsonic activity assessment of human intravenous immunoglobulin preparations against drug-resistant bacteria.

We have used the ability of opsonized bacteria to stimulate luminol-enhanced chemiluminescence (CL) of human polymorphonuclear leukocytes (PMN) to examine the opsonic capabilities of commercially available human intravenous immunoglobulin (i.v.Ig) preparations. The method was tested against 14 strains of drug-resistant gram-positive bacteria (including methicillin-resistant Staphylococcus aureus, hetero-vancomycin-resistant S. aureus, vancomycin-resistant enterococci, penicillin-resistant Streptococcus pneumoniae), and 23 strains of gram-negative bacteria (including extended-spectrum beta-lactamase-producing bacteria, metallo-beta-lactamase-producing bacteria, beta-lactamase-negative ampicillin-resistant Haemophilus influenzae). An Fc-intact i.v.Ig preparation treated with polyethylene glycol (PEG) was evaluated for opsonization effectiveness against these bacteria in vitro. The opsonization of these organisms was enhanced by an Fc-intact i.v.Ig, and the opsonic activity was dose dependent. A pepsin-treated i.v.Ig preparation exhibited poor opsonic activity for all bacteria tested. These results suggest that Fc-intact i.v.Ig, which augments opsonic activity against various drug-resistant bacteria, will be a useful addition to the treatment of severe bacterial infections in immunocompromised patients with impaired serum opsonic capacity.

Production of anti-Candida antibodies in mice with gut colonization of Candida albicans.

BACKGROUND: Production of antibodies that are specific for allergens is an important pathological process in inflammatory allergic diseases. These contain the antibodies against antigens of Candida albicans, one of the normal microbial flora in an intestinal tract. We studied the effects of the prednisolone administration on the production of anti-Candida antibodies in the gastrointestinally C. albicans-colonized mice. METHODS AND MATERIALS: BALB/c mice, treated with antibacterial antibiotics to decontaminate indigenous intestinal bacterial flora, were inoculated intragastrically with C. albicans. The mice, in which C. albicans grows intestinally, were administered prednisolone to induce temporary immunosuppression. The Candida growth in their intestinal tract and their antibody response to Candida were examined. RESULTS: Antibiotic treatment allowed establishment of C. albicans gastrointestinal colonization, but did not cause subsequent systemic dissemination of C. albicans in all the animals. When these animals received an additional treatment with prednisolone, they showed a significantly higher population of C. albicans in their feces than those of animals treated with antibiotics alone, and the organisms were recovered even from their kidney. This systemic dissemination by C. albicans appeared to be temporal, because all the mice survived without any symptoms for more than 2 months. Examination of the serum titers of total immunoglobulin (Ig)E antibodies and specific IgE and IgG antibodies against Candida antigens demonstrated that titers of total IgE increased, partially by day 14 and clearly at day 27, in prednisolone-treated Candida-colonized mice. Without prednisolone treatment, an increment of the serum titer was scarcely observed. By day 27, corresponding to the increase of total IgE, the anti-Candida IgE and IgG titer increased in mice of the prednisolone-treated group. CONCLUSION: Administration of prednisolone to Candida-colonized mice can induce production of the IgG, IgE antibodies against Candida antigens, perhaps through temporal systemic dissemination of Candida from the intestinal tract.