Expression of immunomodulatory genes in human monocytes induced by voriconazole in the presence of Aspergillus fumigatus

We assessed the effect of voriconazole (VRC) on the expression and release of selected cytokines and chemokines in the THP-1 human monocytic cell line in response to Aspergillus fumigatus hyphal fragments (HF) by cDNA microarray analysis, reverse transcriptase (RT) PCR, and enzyme-linked immunosorbent assay. Stimulation of THP-1 cells by HF alone caused a significant up-regulation of CCL4 (MIP1B) and CCL16, while CCL2 (MCP1) was down-regulated. By comparison, in the presence of VRC, a large number of genes such as CCL3 (MIP1A), CCL4 (MIP1B), CCL5 (RANTES), CCL7 (MCP3), CCL11 (EOTAXIN), CCL15 (MIP1Delta), CXCL6, and CXCL13 were strongly up-regulated in THP-1 cells challenged by HF, whereas CCL20 (MIP3A) and CCL21 (MIP2) were down-regulated. Among five genes differentially expressed in THP-1 cells, IL12A, IL12B, and IL-16 were down-regulated whereas IL-11 and TGFB1 were significantly up-regulated in the presence of VRC. The inflammation-related genes IFNgamma, IL1R1, and TNFA were also up-regulated in THP-1 cells exposed to HF only in the presence of VRC. RT-PCR of four selected genes validated the results of microarrays. The release of interleukin 1beta (IL-1beta) and IL-12 was significantly increased from monocytes stimulated either by HF alone (P < 0.05) or in the presence of VRC (P < 0.01 and P < 0.05, respectively). In contrast, tumor necrosis factor alpha release from monocytes was enhanced only in the presence of VRC (P < 0.01). The chemokines monocyte chemoattractant protein 1 and macrophage inflammatory protein 1beta were decreased under both conditions (P < 0.01). These results demonstrate that in the presence of VRC, HF induces a more pronounced profile of gene expression in THP-1 cells than HF alone, potentially leading to more-efficient host resistance to A. fumigatus.

Effects of lipid formulations of amphotericin B on activity of human monocytes against Aspergillus fumigatus

The immunomodulatory effects of liposomal amphotericin B (LAMB), amphotericin B lipid complex, and amphotericin B colloidal dispersion (ABCD) on antifungal activity of human monocytes (MNCs), an important component of antifungal host defense, against Aspergillus fumigatus were compared to those of deoxycholate amphotericin B (DAMB). MNCs from healthy volunteers were incubated with 1 or 5 microg/ml DAMB and 5 or 25 microg/ml lipid formulations for 22 h. Drug-pretreated or untreated MNCs were then washed and assayed for the following: (i) activity against A. fumigatus hyphae by XTT assay at MNC:hypha ratios of 10:1 and 20:1; (ii) production of superoxide anion (O2-) from MNCs in response to hyphae by cytochrome c reduction; (iii) production of hydrogen peroxide (H2O2) and H2O2-dependent intracellular intermediates (DIIs), such as OH- and HOCl, from MNCs in response to A. fumigatus culture supernatant by flow cytometric measurement of dihydrorhodamine-1,2,3 oxidation. With the exception of 1 microg/ml DAMB and 5 mug/ml LAMB or ABCD at 10:1, all amphotericin B formulations at both concentrations and MNC:hypha ratios enhanced MNC-induced damage of A. fumigatus hyphae compared to results with untreated cells (P < 0.01). While MNC O2- production upon hyphal challenge, an early event in oxidative burst, was not affected by the drugs, production of H2O2 and DIIs, late events, were significantly increased by all four drugs (P < 0.01). At clinically relevant concentrations, both conventional amphotericin B and its lipid formulations enhance antihyphal activity of MNCs against A. fumigatus in association with significant augmentation of H2O2 and DIIs but not O2-, further demonstrating the immunomodulatory antifungal activities of these agents.

Differential expression of cytokines and chemokines in human monocytes induced by lipid formulations of amphotericin B

The immunomodulatory effects of liposomal amphotericin B (LAMB), amphotericin B lipid complex (ABLC), and amphotericin B colloidal dispersion (ABCD) on mRNA and protein profiles of five cytokines and chemokines expressed by human monocyte-enriched mononuclear leukocytes (MNCs) were comprehensively evaluated by semiquantitative reverse transcription-PCR and enzyme-linked immunosorbent assays; they were compared to those of deoxycholate amphotericin B (DAMB). mRNAs of interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1ra), tumor necrosis factor alpha (TNF-alpha), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 1beta (MIP-1beta) were assessed after treatment of MNCs with each drug for 0.5, 2, 6, and 22 h. The cytokine protein profiles were obtained after incubation of MNCs with the drugs for 2 h (TNF-alpha) or 6 h (all the others). In the mRNA studies, DAMB resulted in an early increase of inflammatory cytokines or chemokines IL-1beta, TNF-alpha, MCP-1, and MIP-1beta (2 to 6 h) and in a late increase of anti-inflammatory IL-1ra (22 h). ABCD showed a general similar trend of inflammatory gene up-regulation. LAMB and ABLC decreased or did not affect IL-1beta and TNF-alpha, whereas ABLC additionally decreased MIP-1beta. In protein measurement studies, DAMB and ABCD up-regulated production of IL-1beta (P < 0.05), decreased the IL-1ra/IL-1beta ratio, and up-regulated the production of MCP-1 and MIP-1beta. In comparison, LAMB and ABLC down-regulated or did not affect the production of these cytokines/chemokines compared to untreated MNCs; furthermore, ABLC tended to increase the IL-1ra/IL-1beta ratio. These studies demonstrate that amphotericin B formulations differentially affect gene expression and release of an array of proinflammatory and anti-inflammatory cytokines that potentially may explain the differences in infusion-related reactions and dose-dependent nephrotoxicity as well as modulation of the host immune response to invasive fungal infections.

Antifungal activities of posaconazole and granulocyte-macrophage colony-stimulating factor ex vivo and in mice with disseminated infection due to Scedosporium prolificans

Invasive infection due to Scedosporium prolificans is characterized by drug resistance and a high rate of mortality. The effects of posaconazole (POS), an investigational antifungal triazole, murine granulocyte-macrophage colony-stimulating factor (GM-CSF), and their combination against S. prolificans were evaluated ex vivo and in a newly developed murine model of disseminated infection due to this organism. When POS was combined with polymorphonuclear leukocytes from untreated or GM-CSF-treated mice (P < 0.01) ex vivo, it had increased activity in terms of the percentage of hyphal damage. Immunocompetent BALB/c mice were infected with 4 x 10(4) conidia of S. prolificans via the lateral tail vein. At 24 h postinfection the mice were treated with GM-CSF (5 microg/kg of body weight/day subcutaneously), POS (50 mg/kg/day by gavage), both agents, or saline only. Half of the brain, lung, liver, and kidney from each animal were cultured; and the other half of each organ was processed for histopathology. The mean survival times were 7.0 +/- 0.3 days for the controls, 7.4 +/- 0.4 days for POS-treated mice, 8.0 +/- 0.3 days for GM-CSF-treated mice (P = 0.08 compared with the results for the controls), and 7.3 +/- 0.3 days for POS-GM-CSF-treated mice. Fungal burdens (determined as the numbers of CFU per gram of tissue) were found in descending orders of magnitude in the kidneys, brains, livers, and lungs. The burdens were significantly reduced in the brains of GM-CSF-treated mice (P < 0.05) and the livers of POS-treated mice (P < 0.05). The numbers of lesions in the organs closely corresponded to the fungal burdens. GM-CSF tended to prolong survival (P = 0.08 compared with the results for the controls). While the combination of POS and GM-CSF showed enhanced activity ex vivo, it did not increase the activities of the two agents against this highly refractory filamentous fungus in mice.

Targeting exposed RNA regions in crystals of the small ribosomal subunits at medium resolution

Within the framework of ribosomal crystallography, the small subunits are being analyzed, using crystals diffracting to 3 A resolution. The medium resolution electron density map of this subunit, obtained by multiple isomorphous replacement, show recognizable morphologies, strikingly similar to the functional active conformer of the small ribosomal subunit. It contains elongated dense features, traceable as RNA chains as well as globular regions into which the structures determined for isolated ribosomal proteins, or other known structural motifs were fitted. To facilitate unbiased map interpretation, metal clusters are being covalently attached either to the surface of the subunits or to DNA oligomers complementary to exposed ribosomal RNA. Two surface cysteines and the 3' end of the 16S ribosomal RNA have been localized. Targeting several additional RNA regions shed light on their relative exposure and confirmed previous studies concerning their functional relevance.

Ribosomal gene disruption in the extreme thermophile Thermus thermophilus HB8. Generation of a mutant lacking ribosomal protein S17

S17 is a primary rRNA-binding protein which has been implicated in ribosome assembly and translational fidelity. We describe the generation and biochemical characterization of an S17 minus ribosomal mutant, a ribosomal protein-lacking mutant obtained in Thermus thermophilus HB8. The S17 mutant was obtained by insertional inactivation of the target gene with the kanamycin adenyl transferase (kat) gene, making use of a Thermus-Escherichia shuttle vector and the natural ability of Thermus to transform. In the final construct used to transform Thermus cells, the S17 coding region was replaced with the kat gene cloned in-frame with the first three amino acids of S17. Hence, in vivo transcription of the kat gene was under the control of the ribosomal operon promoter. As in Escherichia coli, the Thermus S17 mutant exhibited a temperature-sensitive phenotype. Two-dimensional PAGE, Western blot, and ELISA confirmed the absence of S17 from the mutant ribosomes. Sucrose-gradient profiles of mutant cells showed a clear separation and normal proportions of 50S and 30S subunits and a normal ratio between them. In addition, the S17 mutant showed the presence of a 20S peak representing assembly-defective particles. The successful re-incorporation of protein S17 into the mutant ribosomes was demonstrated when reconstitution with isolated S17 was performed at 60 degrees C.

Structural and functional studies on the overproduced L11 protein from Thermus thermophilus

The L11 ribosomal protein from Thermus thermophilus (TthL11) has been overproduced and purified to homogeneity using a two-step purification protocol. The overproduced protein carries a similar methylation pattern at Lys-3 as does its homolog from Escherichia coli. Chymotrypsin digested only a small part of the TthL11 protein and did not cleave TthL11 into two peptides, as in the case of EcoL11, but produced only a single N-terminal peptide. Tryptic digestion of TthL11 also produced an N-terminal peptide, in contrast to the C-terminal peptide obtained with L11 from Bacillus stearothermophilus. The recombinant protein forms a specific complex with a 55-nt 23S rRNA fragment known to interact with members of the L11 family from several organisms. Cooperative binding of TthL11 and thiostrepton to 23S rRNA leads to an increased protection of TthL11 from tryptic digestion. The similar structural and biochemical properties as well as the significant homology between L11 from E. coli and B. stearothermophilus with the corresponding protein from Thermus thermophilus indicate an evolutionarily conserved protein important for ribosome function.

Purification and partial characterization of a tripeptidase from Pediococcus pentosaceus K9.2

A tripeptidase was purified from the cytoplasm of Pediococcus pentosaceus K9.2 by anion-exchange chromatography, gel filtration chromatography, and high-performance liquid chromatography. The molecular mass of the enzyme was estimated by gel filtration at 100,000 Da. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified peptidase showed one protein band of 45,000 Da. Optimal enzyme activity was obtained at pH 7.0 and at 50 degrees C. The peptidase hydrolyzed all tripeptides tested. Cleavage was not observed with dipeptides, oligopeptides, or amino acid-p-nitroanilide derivatives. Strong inhibition of activity was caused by EDTA, 1,10-phenanthroline, dithiothreitol, and beta-mercaptoethanol, whereas phenylmethylsulfonyl fluoride and sulfur-reactive reagents had no effect on peptidase activity. Mg2+, Mn2+, and Ca2+ stimulated the hydrolyzing activity of the enzyme. The 20 N-terminal amino acids of the tripeptidase from P. pentosaceus had 84% identity with those from the corresponding N-terminal region of the tripeptidase from Lactococcus lactis subsp. cremoris Wg2.

Human parvovirus B19: immunity of Greek females and prenatal investigation of hydrops fetalis

Sera from 308 healthy Greek females of reproductive age were examined for specific IgG antibodies to human parvovirus B19 by recombinant-Elisa to determine the immunity rates of this part of population to parvovirus B19. Also paired maternal sera and amniotic fluids from nine pregnancies with hydrops fetalis were investigated for specific IgG and IgM antibodies and parvovirus DNA by polymerase chain reaction and southern hybridization analysis. The latter study was conducted to find out the participation of parvovirus B19 infection in hydrops fetalis cases in Greece. The overall prevalence of IgG antibodies in healthy Greek females was at a rate of 57.8% rising with age. One case of hydrops fetalis out of the nine examined, was diagnosed prenatally as parvovirus B19 maternal-fetal infection. It was a twin pregnancy with one fetus hydropic and the other growth retarded. Premature birth of liveborn infants was followed by neonatal death, 48 h after delivery. The contribution of parvovirus B19 in cases of non-immune hydrops fetalis was at 11% in this part of the world.

Prenatal diagnosis of fetal cytomegalovirus infection in seropositive pregnant women

Thirty two pregnant women, immune to human cytomegalovirus (HCMV) before conception, were examined with a combination of amniocentesis, and blood sampling for fetal HCMV infection. The pregnant women had no history of recurrent infection and they all had normal ultrasonographic findings. Maternal sera and amniotic fluids were examined for anti-HCMV antibodies and viral DNA by enzyme immunoassay and polymerase chain reaction (PCR). All maternal sera were negative for viral DNA and IgM anti-HCMV antibodies. However, HCMV DNA was detected in the amniotic fluid of four pregnant women. These four cases were considered as fetal HCMV infections. Three of them were followed up after birth. The three neonates appeared clinically normal at birth, but HCMV DNA was detected in their urine specimens and in two of them in the cord blood sera. Although the neonates were asymptomatic at birth, the possibility of developing sequelae later on, cannot be excluded. The results show that HCMV recurrent maternal infection is silent and difficult to be suspected and diagnosed. They also show that fetal HCMV infection is not rare among pre-immune pregnant women.