[Evaluation and utility of the E-test and Neo-Sensitabs methods in studying fluconazole yeast susceptibility]

Standardized broth dilution methods are cumbersome for routine use in a clinical laboratory to study antifungal yeast susceptibility. Recently, the CLSI has standardized a disk diffusion method faster and more suitable to study fluconazole and voriconazole susceptibility. The objectives of the present study were to determine: a) the suitability of the Neo-Sensitabs tablets to study fluconazole susceptibility; b) whether Mueller-Hinton agar with methylene blue (MHAG-AM) could be used in the E-test method; and c) the interaction of the methylene blue with RPMI medium. A total of 84 blood stream yeast isolates were used (25 C. albicans, 7 C. parapsilosis, 10 C. tropicalis, 12 C. glabrata, 7 C. krusei, 4 C. lusitaniae and 19 C. neoformans). The methylene blue makes sharper inhibition zones both in MHAG-AM and RPMI media. With fluconazole Neo-Sensitabs tablets, the lowest percentage of very major errors was found in MHAG-AM and the greatest in RPMIG. In both diffusion methods and culture media, the very major errors were found in C. albicans, C. tropicalis (only with Neo-Sensitabs) and C. glabrata. The percentage of fluconazole-resistant strains was lower in the media that contained glucose (2%). Neo-Sensitabs tablets are a reliable alternative to the dilution methods to detect fluconazole susceptibility. In the case of resistance, more studies are required; nevertheless, inhibition zone > or =17 mm should be applied to define fluconazole resistance.

Single-nucleotide polymorphisms in the epsilon-globin gene for differentiating primate infraorders

Molecular methods are being used to enforce wildlife conservation laws by identifying the species or the geographic origin of an unknown sample. However, the promising use of single-nucleotide polymorphisms (SNPs) in this field is still widely unexplored. In the present work, we have developed a reliable and easy method based on single-base extension technology for the scoring of 3 SNPs in the epsilon-globin gene that successfully identifies the primate infraorder a sample belongs to. Since primates are of high conservation concern and different infraorders are distributed in specific parts of the world, this method will serve for an initial potentially automated screening of the taxonomy and geographic origin of an unknown primate sample arriving at customs.

Pharmacological inhibition and silencing of classical IKK-NF-κB pathway by siRNA sensitizes cancer cells to doxorubicin

2059

Background: The IKK/NF-κB pathway (IKK1, IKK2 and NEMO; p65, p50, p52, c-Rel, RelB) is involved in chemoresistance. NF-κB is activable by either a classical or an alternative Ipathway. Here we studied whether NF-κB inhibitors sensitized cells to doxorubicin (dox), and assessed the role of individual IKK or NF-κB subunits by RNA interference [ small interfering RNA (siRNA)] on doxorubicin sensitization. Methods: We used BT474 and MDA-MB453 cells (breast) and HeLa cells (cervix). NF-κB inhibitors were bortezomib (Velcade, a proteasome inhibitor, which inhibits NF-κB by promoting accumulation of the inhibitory Iκ B-α) and a NEMO-Binding-Peptide (NBP, which prevents IKK proteins from complexing). NF-κB DNA binding activity was measured by EMSA. Western blot was used to assess nuclear translocation of individual NF-κB subunits (Iκ B-α, p65, c-Rel, RelB, p50 and p52). BT474 and MDA-MB453 cells were cultured with dox with/without NF-κB inhibitors and viability was assayed by MTT. siRNA was used to transiently down-regulate subunits that act preferentially on the classical NF-κ B (p65, p52, c-Rel, or NEMO) or on the alternative pathway (RelB) in HeLa cells. Chemosensitivity of transfected and control cells to dox was measured by MTT. Results: Dox increased NF-κB activity in BT474 and HeLa cells, as assayed by EMSA and/or by showing Iκ B-α degradation and phosphorylation of p65. Pretreatment of BT474 cells with bortezomib followed by dox resulted in a 30% reduction in cell viability compared to dox alone. Moreover, a 40% higher dox sensitivity was observed when cells were pretreated with a NEMO-Binding-Peptide. Similar data were obtained in MDA-MB453 cells. Transient down-regulation of key members of the classical IKK- NF-κB pathway (p65, p52, c-Rel and NEMO) by siRNA in HeLa cells lead to a 30% increase in dox cytotoxicity. In contrast, silencing of RelB, a key subunit of the alternative pathway, had no effect on dox cytotoxicity under our assay conditions. Conclusions: NF-κB inhibition sensitized cells to dox, implying directly p65, p52, c-Rel and NEMO subunits in chemoresistance, but not RelB. These findings suggest that selective inhibition of the classical IKK-NF-κB pathway is sufficient to improve dox antitumor effects.

[Table: see text]

[In vitro activity of voriconazole against yeast and algae isolates according to new resistance pattern cut-off points]

Voriconazole is a second-generation triazole derived from fluconazole but with greater potency and spectrum of activity, showing good in vitro activity against Candida, Cryptococcus and Aspergillus species, and other filamentous and dimorphic fungi. It can be administered orally or intravenously. It was initially approved in 2002 by the U.S. Food and Drug Administration as a treatment option for invasive aspergillosis and Fusarium and S. apiospermum infections showing resistance or intolerance to other antifungals; later on, it also received approval in the United States and Europe as a treatment option for esophageal candidiasis; candida infection in non-neutropenic patients; disseminated candidiasis of skin, abdomen, kidney and bladder; and injuries. Recently, the Clinical Laboratory Standard Institute established some provisional break points for voriconazole, classifying isolates with an MIC<or=1 mg/l as susceptible, those with a 2 mg/l MIC as susceptible-dose dependent, and those with an MIC>or=4 mg/l as resistant. In line with these new data, we performed a systematic review of literature on in vitro activity of voriconazole against yeast and algae isolates, and compared it to that of fluconazole and itraconazole. The review included a total of 27,340 yeast isolates, 24,177 of Candida species, 2,726 of Cryptococcus species, 453 of other species, and 104 Prototheca. The yeast isolates resistant to voriconazole is approximately 1%, and 71% of fluconazole-resistant isolates are susceptible to voriconazole.

Reduced expression of the TrkB receptor in Huntington's disease mouse models and in human brain

Deficits of neurotrophic support caused by reduced levels of brain-derived neurotrophic factor (BDNF) have been implicated in the selective vulnerability of striatal neurones in Huntington's disease (HD). Therapeutic strategies based on BDNF administration have been proposed to slow or prevent the disease progression. However, the effectiveness of BDNF may depend on the proper expression of its receptor TrkB. In this study, we analysed the expression of TrkB in several HD models and in postmortem HD brains. We found a specific reduction of TrkB receptors in transgenic exon-1 and full-length knock-in HD mouse models and also in the motor cortex and caudate nucleus of HD brains. Our findings also demonstrated that continuous expression of mutant huntingtin is required to down-regulate TrkB levels. This was shown by findings in an inducible HD mouse model showing rescue of TrkB by turning off mutant huntingtin expression. Interestingly, the length of the polyglutamine tract in huntingtin appears to modulate the reduction of TrkB. Finally, to analyse the effect of BDNF in TrkB we compared TrkB expression in mutant huntingtin R6/1 and double mutant (R6/1 : BDNF+/-) mice. Similar TrkB expression was found in both transgenic mice suggesting that reduced TrkB is not a direct consequence of decreased BDNF. Therefore, taken together our findings identify TrkB as an additional component that potentially might contribute to the altered neurotrophic support in HD.

Frequency and distribution of chromosome abnormalities in human spermatozoa

This study reviews the frequency and distribution of numerical and structural chromosomal abnormalities in spermatozoa from normal men obtained by the human-hamster system and by multicolor-FISH analysis on decondensed sperm nuclei. Results from large sperm karyotyping series analyzed by chromosome banding techniques and results from multicolor FISH in sperm nuclei (of at least 10(4) spermatozoa per donor and per probe) were reviewed in order to establish baseline values of the sperm chromosome abnormalities in normal men. In karyotyping studies, the mean disomy frequency in human sperm is 0.03% for each of the autosomes, and 0.11% for the sex chromosomes, lower than those reported in sperm nuclei by FISH studies using a similar methodology (0.09% and 0.26%, respectively). Both types of studies coincide in that chromosome 21 and sex chromosomes have a greater tendency to suffer segregation errors than the rest of the autosomes. The mean incidence of diploidy, only available from multicolor FISH in sperm nuclei, is 0.19%. Inter-donor differences observed for disomy and diploidy frequencies among FISH studies of decondensed sperm nuclei using a similar methodology could reflect real differences among normal men, but they could also reflect the subjective application of the scoring criteria among laboratories. The mean frequency of structural aberrations in sperm karyotypes is 6.6%, including all chromosome types of abnormalities. Chromosome 9 shows a high susceptibility to be broken and 50% of the breakpoints are located in 9q, between the centromere and the 9qh+ region. Structural chromosome aberrations for chromosomes 1 and 9 have also been analyzed in human sperm nuclei by multicolor FISH. Unfortunately, this assay does not allow to determine the specific type of structural aberrations observed in sperm nuclei. An association between advancing donor age and increased frequency of numerical and structural chromosome abnormalities has been reported in spermatozoa of normal men.

[Activity of voriconazole against yeasts isolated from blood culture determined by two methods]

The in vitro activity of voriconazole has been determined by two methods: the reference M27-A2 and the marketed Sensititre YeastOne microdilution colorimetric method. The agreement (+/-2 dilutions) and correlation between methods as well as the percentage of errors has been determined. A total of 144 yeasts (47 Candida albicans, 52 C. parapsilosis, 13 C. tropicalis, 10 C. krusei, 9 C. glabrata, 2 C. guilliermondii, 1 C. colliculosa, 1 C. dubliniensis, 2 Trichosporum asahii, 1 T. mucoide, 1 Trichosporum spp., 1 Kloakera apis, 2 Pichia ohmeri, and 2 Rhodotorula glutinis) isolated from blood culture between October 2002 and May 2005 were assayed. Voriconazole has shown good in vitro activity. The rate of voriconazole-susceptible (MIC < or =1 mg/l) strains was 97% and the MIC90 0.25 mg/l by the two methods. The overall percentage of agreement between methods was 86% (range 44.23-100%) and the Pearson's coefficient of correlation was 0.961. Categorical agreement was strain dependent and ranged from 84.6% for emergent yeasts to 100% for the other species tested except for C. glabrata (66.6%). No major or very major errors were found, the percentage of minor errors being 1.38%. Only one C. tropicalis and one C. glabrata strain were resistant (MIC > or =4 mg/l) to voriconazole (1.38%) by the reference method. The colorimetric method identified the voriconazole-resistant C. tropicalis strain, and classified the C. glabrata as susceptible-dose dependent. The colorimetric method is a potential alternative method for testing the susceptibility of yeast in a clinical laboratory and identifies the susceptible strains (100% agreement) very well. Nevertheless, further studies including more voriconazole-resistant strains are required to determine the ability of the method to identify resistance, which is the goal of susceptibility tests.

Circulating IL-18 concentration is associated with insulin sensitivity and glucose tolerance through increased fat-free mass

AIMS/HYPOTHESIS

Knowledge of the factors which simultaneously contribute to insulin-resistance-related inflammation may contribute to early therapeutic targeting. IL-18 has recently been described as one of the factors which, in addition to insulin resistance, may also contribute to atherosclerosis. However, the source of IL-18 is not well characterised.

MATERIALS AND METHODS

We aimed to study body composition (bioelectric impedance), glucose tolerance (OGTT) and insulin sensitivity (minimal model method) in relation to serum IL-18 (ELISA) concentration in 144 otherwise healthy men aged 51.9+/-12.5 years.

RESULTS

In contrast to previous observations in women, circulating IL-18 was not significantly associated with BMI (r=0.12, p=0.1) or WHR (r=0.08, p=0.3). IL-18 was also not associated with absolute or percent fat mass (bioelectric impedance, p>0.20) but, interestingly, it was significantly linked to fat-free mass (p=0.03). Serum IL-18 increased with each quartile of fat-free mass, corresponding to values of < or = 64.2; >64.2 to < or = 71.6; >71.6 to < or = 80.9; and > or = 80.9 kg (ANOVA, p<0.0001). IL-18 was more closely associated with postload glucose during an OGTT (p=0.04) rather than with fasting glucose (p=0.1). HbA1c (p=0.03), HDL-cholesterol (p=0.04) and serum triglycerides (p=0.03) and parameters of systemic inflammation (C-reactive protein, p=0.02) were also significantly associated with circulating IL-18. Insulin sensitivity (minimal model analysis) was linked to circulating IL-18 (p=0.01). In a multiple linear regression analysis this relationship remained significant after controlling for BMI, age and glucose tolerance status. In another model, both fat-free mass and insulin sensitivity contributed to 10% of IL-18 variance.

CONCLUSIONS/INTERPRETATION

Fat mass does not seem to influence circulating IL-18, as initially proposed. In contrast, the fat-free mass compartment (a well-known confounder in the evaluation of insulin sensitivity) may significantly contribute to the relationship between IL-18 and insulin action.

Long-Term Expression of Erythropoietin from Myoblasts Immobilized in Biocompatible and Neovascularized Microcapsules

The present paper investigates the long-term functionality of an ex vivo gene therapy approach based on cell microencapsulation for the continuous delivery of erythropoietin (EPO) without implementation of immunosuppressive protocols. Polymer microcapsules (0.5 ml) loaded with EPO-secreting C(2)C(12) myoblasts and releasing 15,490 +/- 600 IU EPO/24 h were implanted in the peritoneum and subcutaneous tissue of syngeneic and allogeneic mice. High and constant hematocrit levels were maintained for more than 100 days in all implanted mice. Capsules retrieved from the peritoneum were free-floating or forming small capsule clusters, and we detected only a weak fibroblast outgrowth in capsules adhered to organs, whereas capsules explanted from the subcutaneous region appeared altogether as a richly vascularized structure with no signs of major host reaction. Interestingly, the functionality of capsules implanted in the allogeneic mice persisted until day 210 after implantation. These results highlight the feasibility of cell encapsulation technology for the long-term delivery of EPO independent of the method of administration and the mouse strain.

Brain-derived neurotrophic factor modulates dopaminergic deficits in a transgenic mouse model of Huntington's disease

Dysfunction of dopaminergic neurons may contribute to motor impairment in Huntington's disease. Here, we study the role of brain-derived neurotrophic factor (BDNF) in alterations of the nigrostriatal system associated with transgenics carrying mutant huntingtin. Using huntingtin-BDNF+/- double-mutant mice, we analyzed the effects of reducing the levels of BDNF expression in a model of Huntington's disease (R6/1). When compared with R6/1 mice, these mice exhibit an increased number of aggregates in the substantia nigra pars compacta. In addition, reduction of BDNF expression exacerbates the dopaminergic neuronal dysfunction seen in mutant huntingtin mice, such as the decrease in retrograde labelling of dopaminergic neurons and striatal dopamine content. However, mutant huntingtin mice with normal or lowered BDNF expression show the same decrease in the anterograde transport, number of dopaminergic neurons and nigral volume. In addition, reduced BDNF expression causes decreased dopamine receptor expression in mutant huntingtin mice. Examination of changes in locomotor activity induced by dopamine receptor agonists revealed that, in comparison with R6/1 mice, the double mutant mice exhibit lower activity in response to amphetamine, but not to apomorphine. In conclusion, these findings demonstrate that the decreased BDNF expression observed in Huntington's disease exacerbates dopaminergic neuronal dysfunction, which may participate in the motor disturbances associated with this neurodegenerative disorder.

Brain-derived neurotrophic factor regulates the onset and severity of motor dysfunction associated with enkephalinergic neuronal degeneration in Huntington's disease

The mechanism that controls the selective vulnerability of striatal neurons in Huntington's disease is unclear. Brain-derived neurotrophic factor (BDNF) protects striatal neurons and is regulated by Huntingtin through the interaction with the neuron-restrictive silencer factor. Here, we demonstrate that the downregulation of BDNF by mutant Huntingtin depends on the length and levels of expression of the CAG repeats in cell cultures. To analyze the functional effects of these changes in BDNF in Huntington's disease, we disrupted the expression of bdnf in a transgenic mouse model by cross-mating bdnf(+/ -) mice with R6/1 mice. Thus, we compared transgenic mice for mutant Huntingtin with different levels of BDNF. Using this double mutant mouse line, we show that the deficit of endogenous BDNF modulates the pathology of Huntington's disease. The decreased levels of this neurotrophin advance the onset of motor dysfunctions and produce more severe uncoordinated movements. This behavioral pathology correlates with the loss of striatal dopamine and cAMP-regulated phosphoprotein-32-positive projection neurons. In particular, the insufficient levels of BDNF cause specific degeneration of the enkephalinergic striatal projection neurons, which are the most affected cells in Huntington's disease. This neuronal dysfunction can specifically be restored by administration of exogenous BDNF. Therefore, the decrease in BDNF levels plays a key role in the specific pathology observed in Huntington's disease by inducing dysfunction of striatal enkephalinergic neurons that produce severe motor dysfunctions. Hence, administration of exogenous BDNF may delay or stop illness progression.

First metacarpal lengthening following traumatic amputation of the thumb: long-term follow-up

Thumb amputation is a relatively frequent injury in industrial accidents, producing a significant effect on hand function. The long-term results of 18 first metacarpal elongations in patients who had had a non-replantable thumb amputation at the metacarpophalangeal level are reported. Lengthening was performed using a unilateral external fixator. After a learning curve with a high complication rate and prolonged treatment, good functional results were obtained after some technical modifications, with eight patients returning to their previous occupation, and the rest requiring a change in their job.

Induction of GABAergic phenotype in a neural stem cell line for transplantation in an excitotoxic model of Huntington's disease

The implementation of cell replacement therapies for Huntington's disease using multipotent neural stem cells (NSCs) requires the specific differentiation into gamma-aminobutyric acid (GABA) neuronal subtype before transplantation. Here we present an efficient culture procedure that induces stable GABAergic neurons from the immortalized striatal neural stem cell line ST14A. This process requires sequential retinoic acid treatment and KCl depolarization. Initial addition of 10 microM retinoic acid increased cell survival and promoted neuronal differentiation. Subsequent stimulation with 40 mM KCl induced specific differentiation into GABAergic neurons, yielding 74% of total cultured cells. KCl-evoked Ca(2+) influx reduced cell proliferation and nestin expression, and induced neurite outgrowth and GABAergic markers as well as GABA contents, release, and uptake. Characterization of the integration, survival, and phenotype of these predifferentiated GABAergic neurons following transplantation into the adult brain in a model of Huntington's disease revealed long-term survival in quinolinate-lesioned striata. Under these conditions, cells maintained their GABAergic phenotype and elaborated neurite processes with synaptic contacts with endogenous neurons. In conclusion, we have generated a homogeneous population of functional GABAergic neurons from a neural stem cell line, which survive and maintain their acquired fate in vivo. These data may lend support to the possibility of cell replacement therapies for Huntington's disease using neural stem cells.

Stabilization of human pancreatic ribonuclease through mutation at its N-terminal edge

Enzyme stability can be an important parameter in the design of recombinant toxins because unstable proteins are often degraded before they can reach their cellular target. There is great interest in the design of human pancreatic ribonuclease variants that could be cytotoxic against tumoral cells. To this end, some residues in the protein need to be substituted, but this may result in a loss of stability. Previous papers have reported the production of N- and C-terminal human pancreatic ribonuclease variants with increased thermal stability. Here, we investigated the contribution of the different amino acid changes at the N-terminus of the protein to its thermostability increase. We show that this increase correlates with the helical propensity of the first alpha-helix of the protein. On the other hand, deletion of the four last residues of the protein does not affect its thermal stability. These results set the basis for the design of a human pancreatic ribonuclease template on which amino acid substitutions can be made that could render the enzyme cytotoxic, without an important loss in its stability.

Anti-infectious properties of the human milk fat globule membrane

Secretory immunoglobulin A (sIgA), the predominant antibody fraction of human milk, represents a major protective factor against neonatal infection. Until now, sIgA had been identified only in the humoral fraction of human milk. For bovine milk an association between sIgA and the milk fat globule (MFG) membranes has been demonstrated. The aim of our study was to assess whether sIgA is associated with the MFG membranes in human milk. Using anti-sIgA-agglutinated human MFG and immune fluorescence microscopy, we demonstrated that sIgA is, in fact, associated with human MFG. Subsequently, by electrophoretic separation of human MFG membranes and Western blotting, we demonstrated specific sIgA bands, suggesting that sIgA is truly an integral part of the human MFG membrane. This may be of physiological relevance, as undigested and functional human MFG are found in the stools of the newborn.

[Recovery of lung function after laparoscopic cholecystectomy: the role of postoperative pain]

OBJECTIVES

Lung function has been shown to deteriorate after laparoscopic cholecystectomy (LC). The present study evaluated 1) the rate of recovery after LC, and 2) the pathogenic role of postoperative pain in functional deterioration.

DESIGN

Lung function was measured 24 hours before LC, upon hospital discharge (48-72 h after LC), and 10 days later. All patients received metamizol after LC until discharge (2 g every 6 h i.v.). Half the patients (analgesia group) received tramadol (150 mg i.m.) 30 minutes before lung function testing on the day of hospital discharge. The remaining patients constituted the control group.

PATIENTS

Twenty healthy subjects (53 4 years old) undergoing LC for gall bladder removal. All signed informed consent forms. Measures and outcomes: Patient characteristics and preoperative lung function results were similar in both groups. LC duration and postoperative course were also similar in both groups. All were discharged without complications within 72 hours after LC. Lung function upon discharge (FVC, FEV1, TLC, PaO2 and AaPO2) had deteriorated in both groups (p<0.001). Deterioration was less marked in the analgesia group (p < 0.05). Ten days later, lung function had normalized for all subjects.

CONCLUSIONS

These results indicate that after LC, 1) lung function is still abnormal when the patient is discharged from hospital, 2) lung function has fully recovered within 10 days, and 3) postoperative pain contributes significantly to temporary deterioration in lung function.

[Choose science! in a historical perspective: changing views on girls' education and the sciences, 1650-1880]

According to recent historiography on women/gender and science, the uneasy relationship between women and the exact sciences only arose when in the last quarter of the nineteenth century secondary education for girls was organised and structured in opposition to boys' education, stressing the importance of a 'modern' curriculum. Before that moment women had taken part in the popular science culture as visitors of public lectures, as amateur and rather more professional scientists and as writers of best selling books on botany, chemistry or physics. This thesis, as argued most convincingly by Patricia Phillips in her book The Scientific Lady (1990), is tested for the Netherlands. Part I deals with recent literature on the history of gender and science. Part II explores the extent to which women had access to eighteenth-century science culture in the Netherlands, and the traces this left on early nineteenth-century education for girls. The author shows that the educational reformer Barbara van Meerten-Schilperoort did indeed pay quite some attention to the 'sciences' in her curriculum proposal as well as in her publications. This confirms the thesis that only when women gained access to formal education in girls' schools next to the state regulated boys' schools for secondary education, were the exact sciences labelled 'masculine', and contrasted with the 'feminine' humanities, in part as a reflection of the respective curricula.

Calmodulin binds to K-Ras, but not to H- or N-Ras, and modulates its downstream signaling

Activation of Ras induces a variety of cellular responses depending on the specific effector activated and the intensity and amplitude of this activation. We have previously shown that calmodulin is an essential molecule in the down-regulation of the Ras/Raf/MEK/extracellularly regulated kinase (ERK) pathway in cultured fibroblasts and that this is due at least in part to an inhibitory effect of calmodulin on Ras activation. Here we show that inhibition of calmodulin synergizes with diverse stimuli (epidermal growth factor, platelet-derived growth factor, bombesin, or fetal bovine serum) to induce ERK activation. Moreover, even in the absence of any added stimuli, activation of Ras by calmodulin inhibition was observed. To identify the calmodulin-binding protein involved in this process, calmodulin affinity chromatography was performed. We show that Ras and Raf from cellular lysates were able to bind to calmodulin. Furthermore, Ras binding to calmodulin was favored in lysates with large amounts of GTP-bound Ras, and it was Raf independent. Interestingly, only one of the Ras isoforms, K-RasB, was able to bind to calmodulin. Furthermore, calmodulin inhibition preferentially activated K-Ras. Interaction between calmodulin and K-RasB is direct and is inhibited by the calmodulin kinase II calmodulin-binding domain. Thus, GTP-bound K-RasB is a calmodulin-binding protein, and we suggest that this binding may be a key element in the modulation of Ras signaling.

Expression of the Pasteurella multocida ompH gene is negatively regulated by the Fur protein

The fur gene of Pasteurella multocida has been cloned by complementation of an Escherichia coli fur mutant. The P. multocida fur gene, which encodes a predicted protein of 147 amino acids, displaying the highest identity (89%) with the same protein of Haemophilus influenzae, is negatively regulated by its own product. By construction of a P. multocida fur mutant, it has been demonstrated that the ompH gene, encoding a major structural protein of the outer membrane, presenting high antigenicity power, is negatively regulated by iron and glucose. Furthermore, wild-type and fur-defective cells of P. multocida show the same level of virulence.

Induction of potent human immunodeficiency virus type 1-specific T-cell-restricted immunity by genetically modified dendritic cells

A novel technology combining replication- and integration-defective human immunodeficiency virus type 1 (HIV-1) vectors with genetically modified dendritic cells was developed in order to induce T-cell immunity. We introduced the vector into dendritic cells as a plasmid DNA using polyethylenimine as the gene delivery system, thereby circumventing the problem of obtaining viral vector expression in the absence of integration. Genetically modified dendritic cells (GMDC) presented viral epitopes efficiently, secreted interleukin 12, and primed both CD4(+) and CD8(+) HIV-specific T cells capable of producing gamma interferon and exerting potent HIV-1-specific cytotoxicity in vitro. In nonhuman primates, subcutaneously injected GMDC migrated into the draining lymph node at an unprecedentedly high rate and expressed the plasmid DNA. The animals presented a vigorous HIV-specific effector cytotoxic-T-lymphocyte (CTL) response as early as 3 weeks after a single immunization, which later developed into a memory CTL response. Interestingly, antibodies did not accompany these CTL responses, indicating that GMDC can induce a pure Th1 type of immune response. Successful induction of a broad and long-lasting HIV-specific cellular immunity is expected to control virus replication in infected individuals.