The hematopoietic stromal microenvironment promotes retrovirus-mediated gene transfer into hematopoietic stem cells

In this study we report on the establishment of novel conditions which permit efficient retrovirus-mediated gene transfer of human adenosine deaminase (ADA) into murine hematopoietic progenitors. Using Southern blot analysis and an ADA probe, we demonstrated that prestimulation of bone marrow cells over an in vitro culture of adherent stromal cell layers (ACLs) for two days provides favorable conditions for gene transfer in the absence of exogenous growth factors. In bone marrow transplant recipients reconstituted with retrovirally-marked cells, ADA was detected in spleen, thymus and bone marrow cells of the recipients eight months after transplantation. These observations were also seen in transplants of embryonal hematopoietic stem cells. By using different incubation protocols, it was found that the developmental fate of hematopoietic stem cells varied with the presence of exogenous growth factors or an ACL in the prestimulation phase. Polyclonal hematopoiesis with multiple clones appearing simultaneously was revealed in mice reconstituted with growth factor-stimulated cells four months after transplantation. This was detected by multiple integration patterns of ADA integration into the genomes of individual colony forming units-spleen (CFU-S) in transplantation recipient mice. In contrast, two to five months after transplantation, polyclonal hematopoiesis was not observed in mice reconstituted with cells infected in the absence of growth factors. It appears that utilization of the bone marrow microenvironment through the use of an ACL results in a narrower spectrum of integration patterns, suggesting that a type of oligoclonal or monoclonal hematopoiesis is occurring. These studies demonstrate that an ACL provides novel conditions for successful gene transfer and stable integration of the vector into the genome. Use of an ACL may be advantageous for successful hematopoietic stem cell gene therapy.

Rapid Prescreening for Antiviral Agents against HIV-1 Based on Their Inhibitory Activity in Site-Directed Immunoassays. II. Porphyrins Reacting with the V3 Loop of gp120

Recent observations that haernin inhibited the replication of the human immunodeficiency virus (HIV-1) and the reaction between the HIV-1 envelope glycoprotein gp120 and antibodies specific for the V3 hypervariable loop of this glycoprotein were an enticement to determine whether or not additional porphyrins had similar activities. Several porphyrin derivatives, particularly meso-tetra (4-carboxyphenyl) porphine, were more potent inhibitors of HIV-1 replication than haernin. They blocked the binding of homologous antibodies to synthetic peptides corresponding to V3 hypervariable loops of 21 distinct HIV-1 isolates, and inhibited the replication in lymphocytic (MT-2) and promonocyte (U937) cell lines of several HIV-1 isolates, tested (IIIB, RF, SF-2, and MN). Compounds with inhibitory activity had a tetrapyrrole ring and, carboxyl or sulphonate groups. However, antiviral activity depended on minor structural difference's between distinct derivatives endowed with these two features. Metalloporphyrins had a drastically reduced antiviral activity in comparison with the corresponding porphyrins. An understanding of the relationship between the structure of porphyrins and their antiviral effects, perceptible from the results presented, is expected to lead to the design of additional derivatives with more potent antiviral activity and to unravelling of molecular details involved in the association between the V3 loop of gp120 and antiviral compounds targeted to this loop.

Functional analysis of Csk and CHK kinases in breast cancer cells

In this report, we analyzed the expression and kinase activities of Csk and CHK kinases in normal breast tissues and breast tumors and their involvement in HRG-mediated signaling in breast cancer cells. Csk expression and kinase activity were abundant in normal human breast tissues, breast carcinomas, and breast cancer cell lines, whereas CHK expression was negative in normal breast tissues and low in some breast tumors and in the MCF-7 breast cancer cell line. CHK kinase activity was not detected in human breast carcinoma tissues (12 of 12) or in the MCF-7 breast cancer cell line (due to the low level of CHK protein expression), but was significantly induced upon heregulin (HRG) stimulation. We have previously shown that CHK associates with the ErbB-2/neu receptor upon HRG stimulation via its SH2 domain and that it down-regulates the ErbB-2/neu-activated Src kinases. Our new findings demonstrate that Csk has no effect on ErbB-2/neu-activated Src kinases upon HRG treatment and that its kinase activity is not modulated by HRG. CHK significantly inhibited in vitro cell growth, transformation, and invasion induced upon HRG stimulation. In addition, tumor growth of wt CHK-transfected MCF-7 cells was significantly inhibited in nude mice. Furthermore, CHK down-regulated c-Src and Lyn protein expression and kinase activity, and the entry into mitosis was delayed in the wt CHK-transfected MCF-7 cells upon HRG treatment. These results indicate that CHK, but not Csk, is involved in HRG-mediated signaling pathways, down-regulates ErbB-2/neu-activated Src kinases, and inhibits invasion and transformation of breast cancer cells upon HRG stimulation. These findings strongly suggest that CHK is a novel negative growth regulator of HRG-mediated ErbB-2/neu and Src family kinase signaling pathways in breast cancer cells.

Duck "beak atrophy and dwarfism syndrome" disease complex: Interplay of novel goose parvovirus-related virus and duck circovirus?

As a newly emerged infectious disease, duck "beak atrophy and dwarfism syndrome (BADS)" disease has caused huge economic losses to waterfowl industry in China since 2015. Novel goose parvovirus-related virus (NGPV) is believed the main pathogen of BADS disease; however, BADS is rarely reproduced by infecting ducks with NGPV alone. As avian circovirus infection causes clinical symptoms similar to BADS, duck circovirus (DuCV) is suspected the minor pathogen of BADS disease. In this study, an investigation was carried out to determine the coinfection of NGPV and DuCV in duck embryos and in ducks with BADS disease. According to our study, the coinfection of emerging NGPV and DuCV was prevalent in East China (Shandong, Jiangsu and Anhui province) and could be vertical transmitted, indicating their cooperative roles in duck BADS disease.

Association between attention deficit hyperactivity disorder and the DXS7 locus

Attention deficit hyperactivity disorder (ADHD) is a prevalent disorder in children. The etiology of this disease is not clear. Genetics studies have suggested the involvement of the dopamine DRD-4 receptor gene and dopamine transporter gene (DAT1). Clinical studies have shown that monoamine oxidase-B (MAO-B) inhibitors are effective in the treatment of ADHD. These findings suggest that monoamine oxidase (MAO) genes might be involved in the origin of ADHD. In the present work, the DXS7 locus of chromosome X, which is closely linked to MAO genes, was selected as a marker to study the possible association between ADHD and MAO genes in the Chinese population. Haplotype-based haplotype relative risk (HHRR) and the transmission disequilibrium test (TDT) methods were employed to analyze the association and the linkage disequilibrium, respectively. Significant association (X(2) = 15.86; 1 df; P < 0.001) and linkage (X(2) = 14.88; 1 df; P < 0.001) were detected between the 157-bp allele of the DXS7 locus and the DSM-III-R-diagnosed ADHD (N = 72) in trios composed of father, mother, and affected offspring. The data suggested that ADHD was associated and in linkage with DXS7 locus.

Percutaneous laser ablation for treatment of locally recurrent papillary thyroid carcinoma <15 mm

AIM

To evaluate the efficacy and safety of ultrasound-guided percutaneous laser ablation (PLA) for recurrent papillary thyroid carcinomas (PTC) <15 mm in the neck.

MATERIALS AND METHODS

A retrospective study was conducted in 21 patients with 27 recurrent PTC lesions who underwent PLA. The extent of ablation was assessed by contrast-enhanced ultrasonography (CEUS) after PLA. Measurement of the volume of tumour and serum thyroglobulin, and clinical evaluation were performed at 7 days, and 1, 3, 6, and 12 months, and every 6 months thereafter.

RESULTS

The procedure was well tolerated. Of 21 patients, 18 were successfully treated in a single session. Incomplete ablation was detected by CEUS in three patients, and a second ablation was performed. The mean largest diameter and the average baseline volume were reduced from 7.5±2.8 mm and 105.4±114 mm³ to 0.4±1 mm and 0.8±2.4 mm³ at the final follow-up.

CONCLUSIONS

Ultrasound-guided PLA is effective for the treatment of recurrent PTCs with a comparable success rate to radio-iodine therapy, and it may become a primary choice of treatment for recurrent PTCs in selected patients who are ineligible for surgery and/or prefer not to have further surgery.

A bicyclic and hsst2 selective somatostatin analogue: design, synthesis, conformational analysis and binding

A backbone bridged and disulfide bridged bicyclic somatostatin analogue, compound 1 (PTR-3205), was designed and synthesized by solid-phase methodology. The binding of compound 1 to the five different somatostatin receptors, expressed in CHO or COS-7 cells, indicate a high degree of selectivity towards hsstr2. The three-dimensional structure of this compound has been determined in DMSO-d(6) and in water by 1H NMR and by molecular dynamics simulations. Similar backbone conformations were observed in both solvents. We have established direct evidence that the backbone of this bicyclic somatostatin analogue assumes a 'folded' conformation in solution, where the lactam ring extends roughly in the plane of the beta-turn. The pharmacophoric region Phe-(D)-Trp-Lys-Thr of compound 1 is in accord with that of both the Veber compound L-363,301 (Merck) and sandostatin. We believe that the enhanced selectivity towards the hsst2 receptor, in comparison with other analogues, is due to its large hydrophobic region, composed of the lactam ring and the Phe side chains at positions 1 and 8.

Multifaceted consequences of anti-gp41 monoclonal antibody 2F5 binding to HIV type 1 virions

A human monoclonal antibody (MAb) (2F5) neutralizing a variety of laboratory strains and clinical isolates of the human immunodeficiency virus type 1 (HIV-1) and binding to an epitope of the envelope glycoprotein gp41 encompassing the amino acid sequence ELDKWA has been described (Muster T et al., J Virol 1993;67:6642-6647). It was suggested that an immunogen eliciting virus-neutralizing antibodies having a specificity similar to that of MAb 2F5 should be considered as a component of HIV-1 vaccines. Efforts in this direction would benefit from understanding the mechanism whereby MAb 2F5 neutralizes the infectivity of HIV-1. The segment of gp41 encompassing residues ELDKWA has so far not been directly implicated in initiation of infection by HIV-1, suggesting that MAb 2F5 might affect other sites on HIV-1 envelope glycoproteins playing a role in virus entry into target cells. We provide here evidence that MAb 2F5 binding to HIV-1 virus particles decreases the accessibility or conformation of the gp41 fusion domain and of gp120 domains, including the binding site for the CD4 cell receptor. These apparently indirect consequences of MAb 2F5 binding to HIV-1 are likely to account for or contribute to the virus-neutralizing activity of this MAb.

Expression of CD95(FAS) by gene transfer does not sensitize K562 to Fas-killing

CD95(FAS/Apo-1) belongs to the family of TNF receptor related molecules and is expressed on many benign and malignant types of cells. CD95 triggering is involved in the apoptotic death of lymphoid cells and may also be important in myelopoiesis. Myeloid leukemia cells are in most cases resistant to CD95 triggering despite expressing the antigen. We reasoned that myeloid leukemic cells can become sensitized to the Fas pathway of cell death if CD95 expression is restored by gene transfer. As a model, we utilized the cell line K562 which does not express CD95 on their cell surface. The gene for CD95 was introduced into K562 cells (by electroporation). As a control, the gene coding for beta-galactosidase was used. The CD95 transfected K562 cells stably expressed CD95, and had a growth pattern comparable to untransfected cells, but still remained resistant to Fas-triggering (tested using recombinant Fas-ligand). Our experiment shows that antigen expression is not a critical determinant of Fas-mediated apoptosis, but further down-stream mechanisms determine the fate of the cells. The transfected cells also had a comparable susceptibility to NK-mediated lysis which shows that the expression of CD95 does not interfere with NK-mediated lysis of target cells.

Antioxidant supplementation prevents oxidation and inflammatory responses induced by sidestream cigarette smoke in old mice

Sidestream cigarette smoke (SSCS) makes up about 85% of significantly toxic environmental tobacco smoke (ETS). Reactive oxygen species (ROS) in SSCS play an important role in the pathogenesis of a wide range of diseases. Interleukin-6 is a pro-inflammatory cytokine and is closely linked with pathology in cardiovascular disease and conditions that have an inflammatory base. Exposure to SSCS through a burning cigarette for 30 min/day, 5 days a week, for 4 months increased interleukin-6 production in spleen and lipid peroxide level in mouse liver. Our findings suggest that ROS induced by SSCS will promote hepatic lipid peroxidation and may also contribute to an increase in interleukin-6 cytokine production. Multiple antioxidants given as a dietary supplement significantly normalized interleukin-6 cytokine production and prevented hepatic lipid peroxidation. We conclude that the SSCS in moderate intake levels increased oxidation and promoted inflammatory cytokine interleukin-6 production, whereas antioxidants prevented these changes.

Fusion-induced apoptosis contributes to thymocyte depletion by a pathogenic human immunodeficiency virus type 1 envelope in the human thymus

The mechanisms of CD4(+) T-cell depletion during human immunodeficiency virus type 1 (HIV-1) infection remain incompletely characterized. Of particular importance is how CD4(+) T cells are depleted within the lymphoid organs, including the lymph nodes and thymus. Herein we characterize the pathogenic mechanisms of an envelope from a rapid progressor (R3A Env) in the NL4-3 backbone (NL4-R3A) which is able to efficiently replicate and deplete CD4(+) thymocytes in the human fetal-thymus organ culture (HF-TOC). We demonstrate that uninterrupted replication is required for continual thymocyte depletion. During depletion, NL4-R3A induces an increase in thymocytes which uptake 7AAD, a marker of cell death, and which express active caspase-3, a marker of apoptosis. While 7AAD uptake is observed predominantly in uninfected thymocytes (p24(-)), active caspase-3 is expressed in both infected (p24(+)) and uninfected thymocytes (p24(-)). When added to HF-TOC with ongoing infection, the protease inhibitor saquinavir efficiently suppresses NL4-R3A replication. In contrast, the fusion inhibitors T20 and C34 allow for sustained HIV-1 production. Interestingly, T20 and C34 effectively prevent thymocyte depletion in spite of this sustained replication. Apoptosis of both p24(-) and p24(+) thymocytes appears to be envelope fusion dependent, as T20, but not saquinavir, is capable of reducing thymocyte apoptosis. Together, our data support a model whereby pathogenic envelope-dependent fusion contributes to thymocyte depletion in HIV-1-infected thymus, correlated with induction of apoptosis in both p24(+) and p24(-) thymocytes.

High-throughput screening method for evaluating spatial repellency and vapour toxicity to mosquitoes

Spatial repellents are an essential tool for personal protection against mosquitoes that bite and transmit disease pathogens to humans. Current repellent screening methods, such as olfactometers and alternative choice tests, are complex systems that require a relatively large quantity of compound (mg). The present study validates a high-throughput spatial repellent screening method using a glass tube that has the ends covered with netting, in addition to treated filters and plastic end caps. The apparatus occupies relatively little space, is easy to decontaminate, and requires small amounts of compound (μg). In a horizontal tube orientation, DEET (N,N-diethyl-meta-toluamide), citronella oil and IR3535 had 1 h half repellent concentration (EC₅₀ ) values of 32, 32 and 298 μg/cm² , respectively, against the Orlando strain of Aedes aegypti (L.) (Diptera: Culicidae). Vertical tube orientation increased EC₅₀ values by approximately two-fold, except IR3535, which remained essentially unchanged. Transfluthrin showed concentration-dependent spatial repellency (1 h EC₅₀  = 0.5 μg/cm² ) without any knockdown, although only in vertical tubes. Transfluthrin showed 50% knockdown in 1 h at 0.5 μg/cm² and 50% mortality at 0.15 μg/cm² in horizontal tubes. In conclusion, this high-throughput screening method is useful for assessing vapour toxicity and the spatial repellency of candidate molecules prior to semi-field and field studies.

Iodide uptake in human anaplastic thyroid carcinoma cells after transfer of the human thyroid peroxidase gene

Human thyroperoxidase (hTPO) is critical for the accumulation of iodide in thyroid tissues. Poorly differentiated and anaplastic thyroid tumours which lack thyroid-specific gene expression fail to accumulate iodide and, therefore, do not respond to iodine-131 therapy. We consequently investigated whether transfer of the hTPO gene is sufficient to restore the iodide-trapping capacity in undifferentiated thyroid and non-thyroid tumour cells. The human anaplastic thyroid carcinoma cell lines C643 and SW1736, the rat Morris hepatoma cell line MH3924A and the rat papillary thyroid carcinoma cell line L2 were used as in vitro model systems. Employing a bicistronic retroviral vector based on the myeloproliferative sarcoma virus for the transfer of the hTPO and the neomycin resistance gene, the C643 cells and SW1736 cells were transfected while the L2 cells and MH3924A cells were infected with retroviral particles. Seven recombinant C643 and seven SW1736 cell lines as well as four recombinant L2 and four MH3924A cell lines were established by neomycin selection. They were studied for hTPO expression using an antibody-based luminescence kit, followed by determination of the enzyme activity in the guaiacol assay and of the iodide uptake capacity in the presence of Na125I. Genetically modified cell lines expressed up to 1,800 times more hTPO as compared to wild type tumour cells. The level of hTPO expression varied significantly between individual neomycin-resistant cell lines, suggesting that the recombinant retroviral DNA was integrated at different sites of the cellular genome. The accumulation of iodide, however, was not significantly enhanced in individual recombinant cell lines, irrespective of low or high hTPO expression. Moreover, there was no correlation between hTPO expression and enzyme activity in individual cell lines. The transduction of the hTPO gene per se is not sufficient to restore iodide trapping in non-iodide-concentrating tumour cells. Future studies will have to concentrate on the possible expression of enzymatically active proteins or the transfer of multiple genes involved in iodide trapping.

Drug Resistance and Gene Transfer Mechanisms in Respiratory/Oral Bacteria

Growing evidence suggests the existence of new antibiotic resistance mechanisms. Recent studies have revealed that quorum-quenching enzymes, such as MacQ, are involved in both antibiotic resistance and cell-cell communication. Furthermore, some small bacterial regulatory RNAs, classified into RNA attenuators and small RNAs, modulate the expression of resistance genes. For example, small RNA sprX, can shape bacterial resistance to glycopeptide antibiotics via specific downregulation of protein SpoVG. Moreover, some bacterial lipocalins capture antibiotics in the extracellular space, contributing to severe multidrug resistance. But this defense mechanism may be influenced by Agr-regulated toxins and liposoluble vitamins. Outer membrane porin proteins and efflux pumps can influence intracellular concentrations of antibiotics. Alterations in target enzymes or antibiotics prevent binding to targets, which act to confer high levels of resistance in respiratory/oral bacteria. As described recently, horizontal gene transfer, including conjugation, transduction and transformation, is common in respiratory/oral microflora. Many conjugative transposons and plasmids discovered to date encode antibiotic resistance proteins and can be transferred from donor bacteria to transient recipient bacteria. New classes of mobile genetic elements are also being identified. For example, nucleic acids that circulate in the bloodstream (circulating nucleic acids) can integrate into the host cell genome by up-regulation of DNA damage and repair pathways. With multidrug resistant bacteria on the rise, new drugs have been developed to combate bacterial antibiotic resistance, such as innate defense regulators, reactive oxygen species and microbial volatile compounds. This review summaries various aspects and mechanisms of antibiotic resistance in the respiratory/oral microbiota. A better understanding of these mechanisms will facilitate minimization of the emergence of antibiotic resistance.

Glucose transport and apoptosis after gene therapy with HSV thymidine kinase

The relation between tumour metabolism and induction of apoptosis by gene therapy was investigated in a rat Morris hepatoma (MH3924A) model expressing the HSV thymidine kinase (HSVtk) gene. In vivo the amount of glucose transporter (GLUT1 and GLUT3 isoforms) expressing cells was determined in tumours of untreated and treated animals using immunohistochemistry. In vitro uptake studies with 2-fluoro-2-deoxy-D-glucose (FDG), 3-O-methylglucose and thymidine (TdR) and a TUNEL (TdT-mediated dUTP nick end labelling) assay for the assessment of apoptosis were done immediately and 24 h after treatment of the recombinant cells with different doses of ganciclovir (GCV). Immunohistochemistry revealed a significant increase in GLUT1 in treated tumours which showed enhanced transport activity for FDG. In vitro the FDG and 3-O-methylglucose uptake increased to 186% when compared with that of the non-treated cells immediately after incubation with GCV. However, 24 h later the FDG uptake had declined to its normal level, whereas the accumulation of 3-O-methylglucose remained elevated. The uptake of TdR, which was determined simultaneously, decreased in the acid-insoluble fraction of the cells to 27% and 11%, respectively, immediately and 24 h after therapy, while in the acid-soluble fraction it increased to 229% and to 167%, respectively. Employing the TUNEL technique, 25% of cells were found to be apoptotic 24 h after the termination of GCV treatment. Inhibition of glucose transport by cytochalasin B or competition with deoxyglucose resulted in a 78% (cytochalasin B) and 88% (deoxyglucose) decrease in FDG uptake in the recombinant hepatoma cells and in an increase in the apoptotic cell fraction. It is concluded that inhibition of enhanced glucose transport in GCV-treated cells increased apoptosis. Therefore, enhanced glucose transport seems to represent a stress reaction of tumour cells dedicated for the prevention of cell death.

Quantitation of minimal residual disease in acute myelogenous leukemia and myelodysplastic syndromes in complete remission by molecular cytogenetics of progenitor cells

Detection of karyotypic clonal abnormalities are prognostically useful in patients with acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS), but cytogenetic methods are not sensitive enough to detect low numbers of residual leukemic cells in patients who have achieved complete remission (CR). Fluorescence in situ hybridization (FISH) and fluorescence activated cell sorting (FACS) were used to investigate the frequency and presence of minimal residual disease (MRD) in AML and MDS patients (n = 28) with monosomy of chromosomes 7, 17 and 18 and trisomy of chromosomes 6, 8, 9 and 10 in CR. MRD was detected in all patients with monosomy 7 (n = 10) and followed by relapse in eight patients after 4.8 +/- 3.1 months. In contrast, persistent leukemic cells occurred in 11/12 patients with trisomy 8, but only three of them relapsed after 7.7 +/- 4.0 months. Cox regression analysis showed that cytogenetic class and levels of clonal cells at CR were related to time to relapse (P = 0.001). The level of MRD identified patients at high and low risk of relapse. High absolute levels of proliferating residual leukemic cells correlated with monosomy 7 and high risk of relapse.

Potentiation of cytotoxicity of adriamycin on human ovarian carcinoma cell line 3AO by low-level ultrasound

The aim of this study was to determine whether the ultrasound, with a dosage that did not lead to acute and delayed inhibition, could potentiate the cytotoxicity of adriamycin to human ovarian carcinoma cell line 3AO in vitro. Drug sensitivity was analyzed by clonogenic assay, cells were treated by adriamycin singly in group ADM (control), adriamycin prior to ultrasound exposure in group ADM + US, and ultrasound irradiation prior to adriamycin administration in group US + ADM. The intracellular drug accumulation in each group was determined by fluorometry. The results were: (1) the values of IC50 were 0.0083, <0.001 and 0.0065 microg/ml in group ADM, ADM + US and US + ADM respectively; the clone surviving rate in group ADM + US and in group US + ADM were decreased (P < 0.001, P < 0.01), compared with control; the surviving rate in group ADM + US was lower than that in group US + ADM (P < 0.01). (2) The intracellular drug accumulations in group ADM + US were promoted (P < 0.01) and not increased significantly in group US + ADM (P > 0.05). These suggested that the low-level ultrasound could enhance the cytotoxicity of adriamycin to human ovarian carcinoma cells and promoted intracellular drug contents played the leading role.

Functional porous composites by blending with solution-processable molecular pores

We present a simple method for rendering non-porous materials porous by solution co-processing with organic cage molecules. This method can be used both for small functional molecules and for polymers, thus creating porous composites by molecular blending, rather than the more traditional approach of supporting functional molecules on pre-frabricated porous supports.

Side chains in transmembrane helices are shorter at helix-helix interfaces

Transmembrane helices from crystallographically determined structures were analyzed to determine the distribution of side chains inside and outside helix-helix interfaces. Two structural characteristics were explored: (1) the number of atoms outside the interfaces that belong to the side chains with the C(alpha) atoms inside the interfaces, as well as the opposite, inside/outside number (conformation-dependent values) and (2) the side-chain length (depends only on the residue type and does not depend on the side-chain conformation). The results showed that the interface side chains tend to be bent away from the interacting helix. The most important finding, however, is that the side chains in the interface areas, on average, are shorter than in the noninterface areas. Proteins 2000;40:429-435.

Possible pandemic threat from new reassortment of influenza A(H7N9) virus in China

Avian influenza A(H7N9) virus re-emerged in China in December 2013, after a decrease in the number of new cases during the preceding six months. Reassortment between influenza A(H7N9) and local H9N2 strains has spread from China's south-east coast to other regions. Three new reassortments of A(H7N9) virus were identified by phylogenetic analysis: between A(H7N9) and Zhejiang-derived strains, Guangdong/Hong Kong-derived strains or Hunan-derived A(H9N2) strains. Our findings suggest there is a possible risk that a pandemic could develop.

Antibody responses of chimpanzees immunized with synthetic peptides corresponding to full-length V3 hypervariable loops of HIV-1 envelope glycoproteins

Immunization of primates or humans with human immunodeficiency virus type 1 (HIV-1) glycoproteins usually elicited moderate immune responses to the principal neutralizing determinant (PND) located within the V3 hypervariable loop of gp120. Since an antibody response to the PND appears to be protective, experiments were carried out to determine the responsiveness of chimpanzees to immunization with synthetic peptides corresponding to the full-length V3 loop. Seven chimpanzees (4 preimmunized with gp160, 2 preimmunized with HIV-1 antigens unrelated to gp160, and 1 unimmunized) were vaccinated with a mixture of full-length V3 loop peptides from 21 distinct HIV-1 isolates (clones) either in unconjugated form or linked to carrier proteins from HIV-1 nef and gag P18, respectively. Six chimpanzees developed high levels of antibodies to the peptides (dilution endpoints 1: greater than 25,000), and 5 had high levels of antibodies to gp120 from HIV-1IIIB (endpoint titers 1: greater than 500,000). Chimpanzees immunized with peptide-carrier conjugates (4) had antibodies to the carrier proteins nef and gag P18, respectively (endpoint titers 1: greater than or equal to 35,000). Virus-neutralizing (VN) antibodies were detected in sera of 5 of 7 chimpanzees, but were present at titers of 1: greater than or equal to 400 only in sera of 2 chimpanzees. One of these was challenged with HIV-1 and was protected against infection, as reported elsewhere. The antibodies were primarily specific for the HIV-1 isolate used for primary immunization before boosting with peptides. The relatively low dilution endpoints of VN antibodies as compared with endpoints determined by site-specific immunoassays probably can be ascribed to imperfect mimicry of conformational epitopes by synthetic peptides. Nevertheless, sequential or simultaneous immunization with recombinant envelope glycoproteins of HIV-1 and selected synthetic peptides offers an approach for eliciting protective immunity against HIV-1.

Anthracyclines in basal breast cancer: The NCIC-CTG trial MA5 comparing adjuvant CMF to CEF

519

Background: MA5 randomized premenopausal women with node-positive early breast cancers to cyclophosphamide- methotrexate-fluorouracil (CMF) or cyclophosphamide-epirubicin-fluorouracil (CEF) adjuvant chemotherapy. This and other trials have shown that adjuvant regimens containing anthracyclines confer significant survival benefit to breast cancer patients. Meta-analyses have revealed most benefit in women with HER2(+) or TOPO2 (+) tumors. Population-based data suggest that patients with a core basal phenotype (negative for hormone receptors and HER2, positive for CK5/6 or EGFR) conversely have worse survival on anthracycline containing vs. CMF regimens. Here we test the hypothesis specified a priori that for basal breast cancers anthracyclines may be inferior, using data from MA5. Methods: From 710 patients in MA5, blocks suitable for tissue microarray construction were recovered for 549. Immunohistochemistry for ER, PR, HER2, Ki67, CK5/6 and EGFR was obtained, allowing stratification of 511 cases into intrinsic biological subtypes by published methods (Cheang MC et al. Clin Cancer Res 2008;14:1368–76). Prespecified analyses were conducted independently by the NCIC- CTG statistical centre. Results: In the CEF arm, patients with core basal tumors had a hazard ratio of 1.8 (log rank p=0.02) for overall survival (OS) relative to the other biological subtypes. In the CMF arm, there was no significant difference (HR 0.9, p = 0.7). The interaction between core basal status and treatment was borderline significant (p=0.06). Relapse free survival differences did not reach significance. Conclusions: Data from this randomized trial supports the hypothesis that anthracycline containing adjuvant chemotherapy regimens are inferior to adjuvant CMF in women with basal breast cancer.

[Table: see text]

No significant financial relationships to disclose.

Circulating natural IgM antibodies and their corresponding human cord blood cell-derived Mabs specifically combat the Tat protein of HIV

OBJECTIVE

IgM antibodies reactive with each of two specifically defined sequences of HIV Tat protein have been identified in sera from both HIV(+) and normal (HIV(-)) humans. This study was designed to confirm that those antibodies are innate immune factors capable of restriction of specific mechanisms of HIV pathogenicity attributed to the Tat protein.

MATERIALS AND METHODS

Antibody-secreting hybridomas were generated from human cord blood cells and processed for monoclonality. Those Mabs reactive with each of the sequences of Tat with which the circulating antibodies are reactive were isolated and their heavy and light chains identified and DNA sequenced. Pools of IgM isolated from blood of normal humans, chimpanzees, rhesus macaques, and mice and the isolated Tat reactive Mabs were tested for capacity to inhibit Tat-induced human T-cell apoptosis.

RESULTS

Human and chimpanzee IgM pools, as well as the human cord blood cell-derived Mabs, showed a definite capacity to inhibit the Tat-induced apoptosis, while the IgM pools of rhesus macaques or of mice did not.

CONCLUSIONS

These studies establish that the circulating IgM of normal humans include innate antibodies capable of restriction of HIV Tat-induced pathogenesis. That capacity is shared by chimpanzee IgM but not by IgM of other primates or of mice. The identification of those human circulating antibodies as innate is confirmed by the display of similar epitopic identity and apoptosis inhibition capacity by Mabs from human cord blood cell hybridomas. Thus, the arsenal of human cord blood cell hybridomas provides a resource by which, specifically, the potential therapeutic role of the identified HIV Tat-reactive Mabs and, broadly, the fundamental role of innate antibodies in infection control may be explored.