High Neutralizing Capacity Research Articles

Donors for SARS-CoV-2 Convalescent Plasma for a Controlled Clinical Trial: Donor Characteristics, Content and Time Course of SARS-CoV-2 Neutralizing Antibodies

Background: Convalescent plasma is one of the treatment options for COVID-19 which is currently being investigated in many clinical trials. Understanding of donor and product characteristics is important for optimization of convalescent plasma. Methods: Patients who had recovered from CO­VID-19 were recruited as donors for COVID-19 convalescent plasma (CCP) for a randomized clinical trial of CCP for treatment of severe COVID-19 (CAPSID Trial). Titers of neutralizing antibodies were measured by a plaque-reduction neutralization test (PRNT). Correlation of antibody titers with host factors and evolution of neutralizing antibody titers over time in repeat donors were analysed. Results: A series of 144 donors (41% females, 59% males; median age 40 years) underwent 319 plasmapheresis procedures providing a median collection volume of 850 mL and a mean number of 2.7 therapeutic units per plasmapheresis. The majority of donors had a mild or moderate course of COVID-19. The titers of neutralizing antibodies varied greatly between CCP donors (from <1:20 to >1:640). Donor factors (gender, age, ABO type, body weight) did not correlate significantly with the titer of neutralizing antibodies. We observed a significant positive correlation of neutralization titers with the number of reported COVID-19 symptoms and with the time from SARS-CoV-2 diagnosis to plasmapheresis. Neutralizing antibody levels were stable or increased over time in 58% of repeat CCP donors. Mean titers of neutralizing antibodies of first donation and last donation of repeat CCP donors did not differ significantly (1:86 at first compared to 1:87 at the last donation). There was a significant correlation of neutralizing antibodies measured by PRNT and anti-SARS-CoV-2 IgG and IgA antibodies which were measured by ELISA. CCP donations with an anti-SARS-CoV-2 IgG antibody content above the 25th percentile were substantially enriched for CCP donations with higher neutralizing antibody levels. Conclusion: We demonstrate the feasibility of collection of a large number of CCP products under a harmonized protocol for a randomized clinical trial. Titers of neutralizing antibodies were stable or increased over time in a subgroup of repeat donors. A history of higher number of COVID-19 symptoms and higher levels of anti-SARS-CoV-2 IgG and IgA antibodies in immunoassays can preselect donations with higher neutralizing capacity.

Awareness on Application of Antacids among Undergraduate Students

Antacids are usually a class of medication that neutralize stomach acidity and makes its pH more neutral.Commonly used self prescribed medications. Antacids usually consist of magnesium, calcium carbonateand aluminium salts in various compounds or in combination. Gastric acid related disorder could be treatedusing antacids.Ingestion of antacids must be followed only after ingestion of Meals. The main aim of thesurvey was to create awareness on application of antacids among undergraduate students. A questionnairewas prepared and administered to 100 participants through an online Google forms link. Study participantsincluded undergraduate students of 18- 26 age group. Method of representation of each output variable wasin pie chart form. The result was then statistically analyzed using SPSS software. The result was analyzedas 64% were aware on the application of antacids. 55% think antacids are only used to neutralize acidity butother research shows it can reduce activity of pepsin. 45% feel common side effects of overusing antacidsare constipation, Diarrhea, Kidney stones. It shows that severe side effects are rare, although they can occurin high-risk patients. But minor problems like change in bowel habits can occur frequently. This studyconcludes that antacids have a high neutralizing capacity and give relief and comfort. Also inactivate Pepsinto relieve symptoms and provide temporary relief and comfort. Natural foods like mint, milk, Banana,ginger can be taken instead of antacids.

Conversion of cryptocrystalline magnesite to MgO nanosheets: Insights into microstructural properties

In this study, cryptocrystalline magnesite was converted into MgO nanosheets using thermal activation and ball milling. The microstructural properties of raw and thermally activated cryptocrystalline magnesite were assessed using advanced and state-of-art analytical equipments such as high-resolution scanning electron microscopy equipped with electron dispersion spectroscopy (HR-SEM-EDS), transmission electron microscopy coupled with EDS (TEM-EDS), the Brunauer–Emmett–Teller (BET), and X-ray Diffraction (XRD). Raw cryptocrystalline magnesite was observed to contain irregular particles lumped together but they were observed to change to nanosheets post calcination at 1000 ℃. The product nanosheets were comprised of octagonal structure-like with varying sizes. The surface area was observed to reduce from 19 m2.g−1 to 13 m2.g−1 for raw magnesite and activated magnesite, respectively. The pore size were observed to increase after the activation process hence confirming that this material is mesoporous. High pore volume may be attributed to thermal decomposition of the magnesium carbonate post emission of CO2. Furthermore, the chemical composition of raw and activated material were observed to change hence proving that the new material has been synthesized. Chemically, raw and treated materials were predominated by Mg, C and O, amongst the traces of Ca and Si. The product material was observed to have high neutralisation capacity by increasing the pH from 7.3 to 10.36 for 0 g and 0.1 g, respectively. Ultimately, the pH was observed to be ≥ 11 hence denoting the alkalinity potential of the material.

Sulfate ion in raw water affects performance of high-basicity PACl coagulants produced by Al(OH)3 dissolution and base-titration: Removal of SPAC particles by coagulation-flocculation, sedimentation, and sand filtration

Many PACl (poly-aluminum chloride) coagulants with different characteristics have been trial-produced in laboratories and commercially produced, but the selection of a proper PACl still requires empirical information and field testing. Even PACls with the same property sometimes show different coagulation performances. In this study, we compared PACls produced by AlCl3-titration and Al(OH)3-dissolution on their performance during coagulation-flocculation, sedimentation, and sand filtration (CSF) processes. The removal targets were particles of superfine powdered activated carbon (SPAC), which are used for efficient adsorptive removal of micropollutants, but strict removal of SPAC is required because of the high risk of their leakage after CSF. PACls of high-basicity produced by AlCl3-titration and Al(OH)3-dissolution were the same in terms of the ferron assay and colloid charge, but their performance in CSF were completely different. High-basicity Al(OH)3-dissolution PACls formed large floc particles and yielded very few remaining SPAC particles in the filtrate, whereas high-basicity AlCl3-titration PACls did not form large floc particles. High-basicity PACls produced by Al(OH)3-dissolution were superior to low-basicity PACl in lowering remaining SPAC particles by the same method because of their high charge neutralization capacity, although their floc formation ability was similar or slightly inferior. However, high-basicity Al(OH)3-dissolution PACl was inferior when the sulfate ion concentration in the raw water was low. Sulfate ions were required in the raw water for high-basicity PACls to be effective in floc formation. In particular, very high sulfate concentrations were required for high-basicity AlCl3-titration PACls. The rate of hydrolysis, which is related to the polymerization of aluminum species, is a key property, besides charge neutralization capacity, for proper coagulation, including formation of large floc particles. The aluminum species in the high-basicity PACls, in particular that produced by AlCl3-titration, was resistant to hydrolysis, but sulfate ions in raw water accelerated the rate of hydrolysis and thereby facilitated floc formation. Normal-basicity Al(OH)3-dissolution PACl was hydrolysis-prone, even without sulfate ions. Aluminum species in the high-basicity AlCl3-titration PACl were mostly those with a molecular weight (MW) of 1–10 kDa, whereas those of high-basicity Al(OH)3-dissolution PACls were mostly characterized by a MW > 10 kDa. Normal-basicity Al(OH)3-dissolution PACl was the least polymerized and contained monomeric species.

Oral immunization of mice with Lactococcus lactis expressing Shiga toxin truncate confers enhanced protection against Shiga toxins of Escherichia coli O157:H7 and Shigella dysenteriae.

Regardless of the communal impact of Shiga toxins, till today neither a specific treatment nor licensed vaccine is available. Lactococcus lactis (L.lactis), generally regarded as safe organism, is well known to provide a valuable approach regarding the oral delivery of vaccines. This study was undertaken to evaluate the protective efficacy of Stx2a1 expressed in nisin-inducible L.lactis, against Shiga toxins (Stx1, Stx2) in mouse model. Oral immunization of BALB/c mice with LL-Stx2a1 elicited significant serum antibody titer with elevated fecal and serum IgA, along with minimized intestinal and kidney damage resulting in survival of immunized animals at 84% and 100% when challenged with 10×LD50 of Escherichia coli O157 and Shigella dysenteriae toxins, respectively. HeLa cells incubated with immune sera and toxin mixture revealed high neutralizing capacity with 90% cell survivability against both the toxins. Mice immunized passively with both toxins and antibody mixture survived the observation period of 15days, and the controls administered with sham sera and toxins were succumbed to death within 3days. Our results revealed protective efficacy and toxin neutralization ability of LL-Stx2a1, proposing it as an oral vaccine candidate against Shiga toxicity mediated by E.coli O157 and S.dysenteriae.

Antibodies to abrogate Andes hantavirus

Emerging Infections Andes hantavirus circulates in rodent reservoirs and can cause hantavirus cardiopulmonary syndrome in humans. This results in a potentially lethal disease for which no vaccines or targeted treatments exist. Garrido et al. screened memory B cells from people that had been infected with Andes hantavirus. Antibodies were isolated from one individual with a high viral neutralization capacity. Two of these antibodies were fully protective against disease in a hamster model, even when given several days after infection. These antibodies target distinct epitopes on the viral glycoprotein and could be developed for use alone or as a combination therapy. Sci. Transl. Med. 10 , eaat6420 (2018).

Large-Scale Screening of HCMV-Seropositive Blood Donors Indicates that HCMV Effectively Escapes from Antibodies by Cell-Associated Spread.

Immunoglobulins are only moderately effective for the treatment of human cytomegalovirus (HCMV) infections, possibly due to ineffectiveness against cell-associated virus spread. To overcome this limitation, we aimed to identify individuals with exceptional antibodies in their plasma that can efficiently block the cell-associated spread of HCMV. A Gaussia luciferase-secreting mutant of the cell-associated HCMV strain Merlin was generated, and luciferase activity evaluated as a readout for the extent of cell-associated focal spread. This reporter virus-based assay was then applied to screen plasma samples from 8400 HCMV-seropositive individuals for their inhibitory effect, including direct-acting antiviral drugs as positive controls. None of the plasmas reduced virus spread to the level of these controls. Even the top-scoring samples that partially reduced luciferase activity in the screening assay failed to inhibit focal growth when reevaluated with a more accurate, immunofluorescence-based assay. Selected sera with high neutralizing capacity against free viruses were analyzed separately, and none of them prevented the focal spread of three recent clinical HCMV isolates nor reduced the number of particles transmitted, as demonstrated with a fluorescent Merlin mutant. We concluded that donors with cell-to-cell-spread-inhibiting plasma are nonexistent or extremely rare, emphasizing cell-associated spread as a highly efficient immune escape mechanism of HCMV.

Carbamoylethyl pullulan: QbD based synthesis, characterization and corneal wound healing potential

Corneal injuries are the major problem arises these days due to excessive use of mobile phone, TV, environment pollution, etc. Thus, a need is to evaluate materials having good corneal wound healing potential. To achieve this goal, pullulan was derivatized using carbamoylethylation and 24 factorial design has been found a good approach for the optimization of synthesis process of carbamoylethyl pullulan (CMEP). The design expert software applied for this purpose suggested significance of the generated model. ATR-FTIR, NMR and XRD spectral attributes validated the structure of CMEP. Interestingly, derivatization of pullulan to CMEP has increased its ΔH from 171.552 J/g to 203.5 J/g and decreased the endothermic transition from 323.44 °C to 248.67 °C. Further, rheological behavior suggested enhanced viscosity after carbamoylethylation indicating increase in H-bonding that further participate in the enhancement of corneal adhesive strength. The CMEP possessed high corneal wound healing property that was associated with its high corneal adhesive strength and oxygen neutralizing capacity. Thus, the findings suggested overwhelming influence of CMEP as a corneal wound healing agent.

HSV-1-SPECIFIC IGG3 TITERS AND NEUTRALIZING ACTIVITY ARE REDUCED IN AD PATIENTS

Human Herpes Simplex Virus type 1 (HSV-1) infection is suggested to play a role in the development of Alzheimer's disease (AD). Thus, the presence of an inverse correlation between HSV-1-specific antibodies (Ab) titers and brain atrophy as evaluated by magnetic resonance was recently described in AD, suggesting a protective role of the HSV-1-specific humoral response (Agostini et al., 2017). HSV-1 can evade immune responses by interfering with activities mediated by immunoglobulin G (IgG) antibodies, as it expresses a receptor that binds the Fc portion of all IgG subclasses with the exception of IgG3. We analyzed whether IgG-mediated serum neutralization activity against HSV-1 differs when individuals with a diagnosis of either AD or Mild Cognitive Impairment (MCI) are compared to age-matched healthy controls (HC). 135 individuals were enrolled in the study: 48 AD, 50 MCI and 37 HC. Serum HSV-1 IgG Ab titers and subclasses were measured by ELISA. IgG neutralizing activity was performed on HSV-1 infected Vero cells and neutralizing antibody (NAb) titers was measured in all sera. Whereas HSV-1-specific IgG1, IgG2 and IgG4 titers were comparable in all groups of individuals, the presence of IgG3 were significantly increased in MCI (86.2 %) compared to AD (71.6%; p=0.05) and to HC (60.6 %; p=0.002). The analysis of IgG neutralizing capacity showed that low IgG3 levels correspond with low neutralizing capacity (NAb titer <100) in all the three groups of the study, without any significant differences. Surprisingly, in AD patients the neutralizing capacity remained low even with the presence of high IgG3 levels (NAb <100), contrary to MCI and HC subjects, where, as expected, high IgG3levels correspond with high neutralizing capacity (NAb titer =120). HSV-1-specific IgG3 titers and neutralizing activity are significantly reduced in AD. As IgG3 plays a key role to challenge the HSV1 immune-evasion, these results reinforce the hypothesis of a pathogenetic role of HSV-1 in AD.

Construction of a hepatitis B virus neutralizing chimeric monoclonal antibody recognizing escape mutants of the viral surface antigen (HBsAg)

Hepatitis B virus (HBV) infection is a global burden on the health-care system and is considered as the tenth leading cause of death in the world. Over 248 million patients are currently suffering from chronic HBV infection worldwide and annual mortality rate of this infection is 686000. The “a” determinant is a hydrophilic region present in all antigenic subtypes of hepatitis B surface antigen (HBsAg), and antibodies against this region can neutralize the virus and are protective against all subtypes. We have recently generated a murine anti-HBs monoclonal antibody (4G4), which can neutralize HBV infection in HepaRG cells and recognize most of the escape mutant forms of HBsAg. Here, we describe the production and characterization of the chimeric human-murine antibody 4G4 (c-4G4). Variable region genes of heavy and light chains of the m-4G4 were cloned and fused to constant regions of human kappa and IgG1 by splice overlap extension (SOE) PCR. The chimeric antibody was expressed in Chinese Hamster Ovary (CHO)-K1 cells and purified from culture supernatant. Competition ELISA proved that both antibodies bind the same epitope within HBsAg. Antigen-binding studies using ELISA and Western blot showed that c-4G4 has retained the affinity and specificity of the parental murine antibody, and displayed a similar pattern of reactivity to 13 escape mutant forms of HBsAg. Both, the parental and c-4G4 showed a comparably high HBV neutralization capacity in cell culture even at the lowest concentration (0.6μg/ml). Due to the ability of c-4G4 to recognize most of the sub-genotypes and escape mutants of HBsAg, this antibody either alone or in combination with other anti-HBs antibodies could be considered as a potent alternative for Hepatitis B immune globulin (HBIG) as an HBV infection prophylactic or for passive immunotherapy against HBV infection.

Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China.

Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in the North China Plain. Sulfate is a major component of fine haze particles. Record sulfate concentrations of up to ~300 μg m-3 were observed during the January 2013 winter haze event in Beijing. State-of-the-art air quality models that rely on sulfate production mechanisms requiring photochemical oxidants cannot predict these high levels because of the weak photochemistry activity during haze events. We find that the missing source of sulfate and particulate matter can be explained by reactive nitrogen chemistry in aerosol water. The aerosol water serves as a reactor, where the alkaline aerosol components trap SO2, which is oxidized by NO2 to form sulfate, whereby high reaction rates are sustained by the high neutralizing capacity of the atmosphere in northern China. This mechanism is self-amplifying because higher aerosol mass concentration corresponds to higher aerosol water content, leading to faster sulfate production and more severe haze pollution.

Screening scFv antibodies against infectious bursal disease virus by co-expression of antigen and antibody in the bacteria display system

We have previously reported an antigen and antibody co-expression (AAC) technology to demonstrate the interaction between a known antigen and antibody. To validate the co-expression system for screening antibody libraries, a single chain fragment variable(scFv)antibody library was constructed from chickens immunized with the VP2 protein of infectious bursal disease virus (IBDV). The genes of both VP2 and scFv antibodies were inserted into the pBFD-Ab-Ag vector. The co-expression library was subjected to three rounds of screening by flow cytometry (FCM) using a polyclonal antibody against VP2 through a bacteria display system. We achieved enrichment of scFv specific for IBDV. 110 individual clones were initially selected and sequenced. Twenty clones were selected based on fluorescence intensity by FCM. The scFv antibodies were expressed by pET-27b in E.coli and purified. The specificity and affinity of the selected scFv antibodies were confirmed by western blotting assay and ELISA analysis. What's more, the neutralizing capacity was measured with IBDV-B87(100 TCID50) in vitro. Four scFvs (clone 8(1), Y8, L10 and L7) showed significant neutralizing capacity. Two of the four scFvs (clone 8(1) and Y8) demonstrated a higher neutralizing activity to IBDV-B87 and the titers were 16,384 and 8,192, respectively. The two scFvs had higher neutralizing capacity than those obtained in previous studies. We demonstrated that the AAC technology could be applied to screen antibody libraries without baiting antigen to make antibody screening process easier and obtain scFvs with higher neutralizing capacity.

Protein content of antivenoms and relationship with their immunochemical reactivity and neutralization assays

Context. Therapy for snakebites relies on the application of antivenoms, which may be produced with different immunogenic mixtures of venom and possess different pharmaceutical characteristics. For these reasons, immunological cross-reactivity and heterologous neutralization were analyzed relative to the protein content of three antivenoms used in the Americas. Methods. The antivenoms studied were composed of equine F(ab’)2 fragments from animals immunized with Crotalinae venoms. The antivenoms were tested against venoms of seven pit viper species from Argentina, seven from Mexico, one from Costa Rica, and one from Colombia. Results. Immunoblotting showed high cross-reactivity of all major protein bands with all the antivenoms tested. ELISA results also showed high cross-reactivity among the different venoms and antivenoms, and a high heterologous neutralization was observed. The results can be interpreted in different ways depending on whether the reactivity is considered in terms of the volume of antivenom used or by the amount of protein contained in this volume of antivenom. The antivenoms with high immunochemical reactivity and neutralizing capacity were those with higher protein content per vial; but when doses were adjusted by protein content, antivenoms of apparently lower neutralizing capacity and immunochemical reactivity showed at least similar potency and reactivity although volumetrically at higher doses. Conclusion. Protein content relative to neutralization potency of different products must be taken into account when antivenoms are compared, in addition to the volume required for therapeutic effect. These results show the importance of obtaining high-affinity and high-avidity antibodies to achieve good neutralization using low protein concentration and low-volume antivenoms.

Neutralization/purification of the wastewaters from printed circuit boards production using waste by-products

The purpose of this work was development of a new method for the neutralization/purification of printed circuit boards wastewater (PCBW) originating from Zagreb, Croatia, using two industrial by-products. PCBW was characterized with low pH value (2.11) and high concentration of TDS (50190 mg L−1), copper (4190 mg L−1) and iron (2660 mg L−1). Waste base (WB), by-product of the alumina production, and waste sludge, by-product of the electrochemical treatment of groundwater, were employed as neutralization/adsorption agents. Due to its high neutralization capacity WB was used for pH adjustment to pH 8 and heavy metals removal from both effluents, yet the final removal of the contaminants down to the regulated values was assessed by adsorption/coagulation with the iron and aluminum rich waste sludge. Following the combined treatment the removal efficiency of iron and copper was higher than 99.99% with their final concentration in the treated water of 0.151 mg L−1 and 0.129 mg L−1, respectively. Following the ozone base oxidation the removal efficiency of the organic contaminants was more than 83%. The successful application of the industrial waste by-products for neutralization/purification of the PCBW with the removal efficiencies of the contaminants comparable or better than those obtained with conventional treatment represented the main advantage of our presented method.

Immunization with a Chimera Consisting of the B Subunit of Shiga Toxin Type 2 and Brucella Lumazine Synthase Confers Total Protection against Shiga Toxins in Mice

The striking feature of enterohemorrhagic Escherichia coli (EHEC) infections is the production of Shiga toxins (Stx) implicated in the development of the life-threatening hemolytic uremic syndrome. Despite the magnitude of the social impact of EHEC infections, no licensed vaccine or effective therapy is available for human use. One of the biggest challenges is to develop an effective and safe immunogen to ensure nontoxicity, as well as a strong input to the immune system to induce long-lasting, high-affinity Abs with anti-Stx-neutralizing capacity. The enzyme lumazine synthase from Brucella spp. (BLS) is a highly stable dimer of pentamers and a scaffold with enormous plasticity on which to display foreign Ags. Taking into account the advantages of BLS and the potential capacity of the B subunit of Stx2 to induce Abs that prevent Stx2 toxicity by blocking its entrance into the host cells, we engineered a new immunogen by inserting the B subunit of Stx2 at the amino termini of BLS. The resulting chimera demonstrated a strong capacity to induce a long-lasting humoral immune response in mice. The chimera induced Abs with high neutralizing capacity for Stx2 and its variants. Moreover, immunized mice were completely protected against i.v. Stx2 challenge, and weaned mice receiving an oral challenge with EHEC were completely protected by the transference of immune sera. We conclude that this novel immunogen represents a promising candidate for vaccine or Ab development with preventive or therapeutic ends, for use in hemolytic uremic syndrome-endemic areas or during future outbreaks caused by pathogenic strains of Stx-producing E. coli.

HIV-1 Autologous Antibody Neutralization Associates with Mother to Child Transmission

The HIV-1 characteristics associated with mother to child transmission (MTCT) are still poorly understood and if known would indicate where intervention strategies should be targeted. In contrast to horizontally infected individuals, exposed infants possess inherited antibodies (Abs) from their mother with the potential to protect against infection. We investigated the HIV-1 gp160 envelope proteins from seven transmitting mothers (TM) whose children were infected either during gestation or soon after delivery and from four non-transmitting mothers (NTM) with similar viral loads and CD4 counts. Using pseudo-typed viruses we tested gp160 envelope glycoproteins for TZM-bl infectivity, CD4 and CCR5 interactions, DC-SIGN capture and transfer and neutralization with an array of common neutralizing Abs (NAbs) (2F5, 2G12, 4E10 and b12) as well as mother and infant plasma. We found no viral correlates associated with HIV-1 MTCT nor did we find differences in neutralization with the panel of NAbs. We did, however, find that TM possessed significantly higher plasma neutralization capacities than NTM (P = 0.002). Furthermore, we found that in utero (IU) TM had a higher neutralization capacity than mothers transmitting either peri - partum (PP) or via breastfeeding (BF) (P = 0.002). Plasma from children infected IU neutralized viruses carrying autologous gp160 viral envelopes as well as those from their corresponding mothers whilst plasma from children infected PP and/or BF demonstrated poor neutralizing capacity. Our results demonstrate heightened autologous NAb responses against gp120/gp41 can associate with a greater risk of HIV-1 MTCT and more specifically in those infants infected IU. Although the number of HIV-1 transmitting pairs is low our results indicate that autologous NAb responses in mothers and infants do not protect against MTCT and may in fact be detrimental when considering IU HIV-1 transmissions.

Overcoming drug-resistant herpes simplex virus (HSV) infection by a humanized antibody

Despite the availability of antiviral chemotherapy, herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections remain a severe global health problem. Of particular concern is the growing incidence of drug resistance in immunocompromised patients, which stresses the urgency to develop new effective treatment alternatives. We have developed a humanized monoclonal antibody (mAb hu2c) that completely abrogates viral cell-to-cell spread, a key mechanism by which HSV-1/2 escapes humoral immune surveillance. Moreover, mAb hu2c neutralized HSV fully independent of complement and/or immune effector cell recruitment in a highly efficient manner. Prophylactic and therapeutic administration of mAb hu2c completely prevented infection-related mortality of severely immunodeficient mice being challenged with a lethal dose of HSV-1. The high neutralization capacity of mAb hu2c was fully maintained toward clinical HSV isolates being multiresistant to standard antiviral drugs, and infection was fully resolved in 7/8 nonobese diabetic/SCID mice being infected with a multidrug resistant HSV-1 patient isolate. Immunohistochemical studies revealed no significant cross-reactivity of the antibody toward human tissues. These features warrant further clinical development of mAb hu2c as an immunotherapeutic compound for the management of severe and particularly drug-resistant HSV infections.

Mining-related contamination of surface water and sediments of the Kafue River drainage system in the Copperbelt district, Zambia: An example of a high neutralization capacity system

Contamination of the Kafue River network in the Copperbelt, northern Zambia, was investigated using sampling and analyses of solid phases and water, speciation modeling, and multivariate statistics. Total metal contents in stream sediments show that the Kafue River and especially its tributaries downstream from the main contamination sources are highly enriched with respect to Cu and exceed the Canadian limit for freshwater sediments. Results of sequential analyses of stream sediments revealed that the amounts of Cu, Co and Mn bound to extractable/carbonate, reducible (poorly crystalline Fe- and Mn oxides and hydroxides) and oxidizable (organic matter and sulfides) fractions are higher than in the residual ( Aqua Regia) fraction. Compared to Cu, Co and Mn, Fe is bound predominantly to the residual fraction. Values of pH in the Kafue River and its tributaries are alkaline in the contaminated area and concentrations of sulfate gradually increase downstream. Water balance based on sulfate indicates that inflow from the most contaminated tributaries is less than 5% of total discharge in the Kafue River. There is a significant input of Cu and Co from multiple contamination sources close to the town of Chingola, located on the Mushishima tributary, but both metals are mostly bound to suspended particles, which settle in the Kafue River. Additional contaminant sources such as the Uchi mine tailings and Nkana smelter are located in the industrial area around Kitwe, but metals released from these sources are mostly found in suspension and are attenuated efficiently. Low Fe/Cu ratios in suspension and mineralogical composition of stream sediments downstream of contaminant sources around Chingola indicate that native copper, Cu-sulfides, and Cu carbonates are present in stream sediments in addition to Cu bound to Fe(III) oxide and hydroxides. The Nkana smelter fingerprint in stream sediments is recognized by the presence of slag glass and a Cu-Fe-S intermediate solid solution (ISS). Speciation modeling suggests a possibility of precipitation of some Cu phases in the most contaminated tributaries such as the Mushishima. In the early dry period (mid-May) dissolved and suspended Cu and Co concentrations are lower than in the advanced dry period (late June). When the scale of mining and related activities in the Copperbelt is taken into account, the environmental impact of mining and related activities on the Kafue River is relatively limited due to a high neutralizing capacity of the mining wastes which control the rapid precipitation of iron oxides and hydroxides as well as adsorption and/or co-precipitation of copper, and cobalt. The high metal content in stream sediments, however, may pose a potential environmental risk during accidental acid spikes, when significant fractions of metals in sediments can be re-mobilized.

Soil phosphorus fractions following annual paper mill biosolids and liming materials application

Industrial by-products such as paper mill biosolids (PB) and different liming materials have been used as fertilizers and amendments in agricultural soils for many decades. However, little is known about the effects of their repeated application on soil nutrient availability, particularly phosphorus (P). A 6-yr field study (2000-2005) was conducted in the province of Quebec to investigate the effect of repeated annual applications of different PB and industrial by-products on selected soil chemical properties, especially soil P fractions. Different PB rates (0 to 90 Mg wet ha-1) and several liming products (lime mud, wood ash, calcitic lime, and Mg by-products) were annually applied to field crops after seeding. Soils were sampled before seeding in May 2003 and at harvest in October 2005. Results showed that HCl-P was the largest P pool, accounting for about 64% of the total P fraction, and that the repeated applications of liming products significantly increased this pool and decreased the organic P pools. The NaOH-Po and residual-P were significantly lower in 2005 than in 2003, indicating that PB application without supplemental P fertilizer inputs enhanced the mobility and/or mineralization of NaOH-Po and the transformation of recalcitrant P to more labile forms with time. Lime mud (LM) was found to be the best liming material owing to its high neutralization capacity and positive effect on soil P availability over time. Key words: Paper mill biosolids, alkaline residuals, lime, wood ash, soil P fractions

Suppressive effect of magnesium oxide materials on cadmium accumulation in winter wheat grain cultivated in a cadmium-contaminated paddy field under annual rice–wheat rotational cultivation

The effectiveness of two kinds of magnesium oxide (MgO) materials, commercial MgO (2250 kg ha −1) and a material derived from MgO and magnesium silicate minerals named ‘MgO-SH-A’ (2250 and 4500 kg ha −11), in suppression of uptake and accumulation of cadmium (Cd) into grain of winter wheat ( Triticum aestivum L. cv. Ayahikari) was examined in a Cd-contaminated alluvial paddy field under annual rice–wheat rotational system. The MgO materials were mixed into the plough-layer soil only once prior to the preceding rice cultivation. Cadmium concentration in wheat grain produced from the non-amendment control exceeded the maximum limit of Cd in wheat grain adopted by FAO/WHO (0.2 mg kg −1). All of the treatments with the MgO materials significantly lowered plant available Cd fraction in the plough-layer soil. However, only the treatment with the commercial MgO at 2250 kg ha −1 produced wheat grain whose Cd concentration was not only significantly lower than that from the control but also less than 0.2 mg kg −1. It is suggested that the significant suppressive effect of the commercial MgO on Cd accumulation in wheat grain would be mainly attributed to its high soil neutralizing capacity as compared to that of MgO-SH-A.