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Nitrogen (N) deposition is projected to substantially increase in the tropics over the coming decades, which is expected to lead to enhanced N saturation and gaseous N emissions from tropical forests (via NO, N 2 O, and N 2). However, it is unclear how N deposition in tropical forests influences both the magnitude of gaseous loss of nitrogen and its partitioning into the N 2 and N 2 O loss mechanisms. Here, for the first time, we employed the acetylene inhibition technique and the 15N-nitrate labeling method to quantify N 2 and N 2 O emission rates for long-term experimentally N-enriched treatments in primary and secondary tropical montane forest. We found that during laboratory incubation under aerobic conditions long-term increased N addition of up to 100 kg N ha−1 yr−1 at Jianfengling forest, China, did not cause a significant increase in either N 2 O or N 2 emissions, or N 2 O/N 2. However, under anaerobic conditions, N 2 O emissions decreased and N 2 emissions increased with increasing N addition in the secondary forest. These changes may be attributed to substantially greater N 2 O reduction to N 2 during denitrification, further supported by the decreased N 2 O/N 2 ratio with increasing N addition. No such effects were observed in the primary forest. In both forests, N addition decreased the contribution of denitrification while increasing the contribution of co-denitrification and heterotrophic nitrification to N 2 O production. Denitrification was the predominant pathway to N 2 production (98–100%) and its contribution was unaffected by N addition. Despite the changes in the contributions of denitrification to N 2 O gas emissions, we detected no change in the abundance of genes associated with denitrification. While the mechanisms for these different responses are not yet clear, our results indicate that the effects of N deposition on gaseous N loss were ecosystem-specific in tropical forests and that the microbial processes responsible for the production of N gases are sensitive to N inputs. Graphical abstract Image 1 Highlights • The effects of N addition on N gas losses were studied for two tropical forests. • The effects on N gas losses was significant in one forest while not in the other. • N addition increased N 2 O reduction to N 2 by denitrification in secondary forest. • Microbial processes contributions to N 2 O productions are sensitive to N additions. • The abundances of denitrification genes did not change after long term N additions. [ABSTRACT FROM AUTHOR]

The impacts of increasing nitrogen (N) deposition on forest ecosystems, including on carbon (C) sequestration, largely depend on the extent to which forests are N-limited and so whether and where deposited N is retained within the ecosystem. The 15 N tracer method can provide excellent insight into the ecosystem fates of N, but while it has been extensively used in temperate forests it has yet to be sufficiently employed in tropical forests, which are often thought not to be N-limited. Here, we used stable isotope 15 NH 4 + and 15 NO 3 − tracers applied as solutions to the forest floor to examine the fates of different forms of N in a tropical montane primary forest with low background atmospheric N deposition (6 kg N ha −1  yr −1 ) in China. We found that a substantial amount of 15 N was assimilated by plants over time and significantly more 15 N was recovered following 15 NO 3 − addition than following 15 NH 4 + addition: 7% and 16% of 15 N were recovered three months after the respective 15 NH 4 + and 15 NO 3 − tracer additions and 11% and 29% respectively after one year. In contrast to plants, the organic layer was only an important short-term sink for deposited N: while 21% and 12% of the 15 N from 15 NH 4 + and 15 NO 3 − additions were accumulated in the organic layer after three months, more than half of the retained 15 N was lost after one year. Mineral soil was the largest sink for deposited N, and the 15 N retained in soil was relatively stable over time for both N forms, with 39% and 32% of the initial 15 N input recovered after one year for 15 NH 4 + and 15 NO 3 − tracer additions, respectively. Overall, the total ecosystem 15 N recovery one year after the 15 NH 4 + and 15 NO 3 − tracer additions was large (60% and 66% respectively), and not significantly different from total recovery after three months, suggesting that a large proportion of deposited N could be retained in the longer term. Based on the measured fate of 15 N one year after labeling and the C:N ratios of different plant components, this tropical forest’s carbon sequestration efficiency is calculated to be 17 kg C per kg N added, comparable to the values reported for temperate and boreal forests in Europe and North America and indicating substantial N limitation of this tropical forest. Our results suggest that anthropogenic N input in moderate levels may contribute to enhance C sequestration in some tropical forests, without significant long-term loss of N to the environment. [ABSTRACT FROM AUTHOR]

Tropical forests, where the soils are nitrogen (N) rich but phosphorus (P) poor, have a disproportionate influence on global carbon (C) and N cycling. While N deposition substantially alters soil C and N retention in tropical forests, whether P input can alleviate these N-induced effects by regulating soil microbial functions remains unclear. We investigated soil microbial taxonomy and functional traits in response to 10-year independent and interactive effects of N and P additions in a primary and a secondary tropical forest in Hainan Island. In the primary forest, N addition boosted oligotrophic bacteria and phosphatase and enriched genes responsible for C-, P-mineralization, nitrification and denitrification, suggesting aggravated P limitation while N excess. This might stimulate P excavation via organic matter mineralization, and enhance N losses, thereby increasing soil CO 2 and N 2 O emissions by 86% and 110%, respectively. Phosphorus and NP additions elevated C-mining enzymes activity mainly due to intensified C limitation, causing 82% increase in CO 2 emission. In secondary forest, P and NP additions reduced phosphatase activity, enriched fungal copiotrophs and increased microbial biomass, suggesting removal of nutrient deficiencies and stimulation of fungal growth. Meanwhile, soil CO 2 emission decreased by 25% and N 2 O emission declined by 52–82% due to alleviated P acquisition from organic matter decomposition and increased microbial C and N immobilization. Overall, N addition accelerates most microbial processes for C and N release in tropical forests. Long-term P addition increases C and N retention via reducing soil CO 2 and N 2 O emissions in the secondary but not primary forest because of strong C limitation to microbial N immobilization. Further, the seasonal and annual variations in CO 2 and N 2 O emissions should be considered in future studies to test the generalization of these findings and predict and model dynamics in greenhouse gas emissions and C and N cycling. [Display omitted] • N and P inputs shift soil fungi towards copiotrophs and bacteria towards oligotrophs in tropical forest. • Soil microbial responses to nutrient inputs differs between primary and secondary forests. • P boosts fungal growth and N retention in secondary forest, reducing soil CO 2 and N 2 O efflux. • N enhances microbial P excavation and denitrification in primary forest, raising CO 2 and N 2 O efflux. • Soil N:P ratio regulates microbial C and N retention and release capacity under N and P inputs. [ABSTRACT FROM AUTHOR]

A number of product development partnerships are actively developing new vaccines to combat infectious diseases in developing countries. To be effective, the products under development should not only be safe, efficacious, and affordable, but they should also have additional desirable technical attributes, including enhanced stability, efficient packaging, and improved ease of delivery. New technologies are now available to achieve these attributes; however, many of the technologies have yet to be adopted by the vaccine industry. This commentary discusses the opportunities and challenges associated with advancing such attributes, especially vaccine thermostability and dose sparing strategies, and the critical issues that must be addressed to bridge the gap between technology development and product development. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:29-33, 2013 [ABSTRACT FROM AUTHOR]

Abstract: Epidermal powder immunization (EPI) can efficiently deliver powdered protein vaccines to the epidermis. A phase I clinical trial was conducted to evaluate powdered trivalent influenza vaccine delivered using the PowderJect ND5.2 delivery system. Subjects received either Fluvirin® IM injection (15μg of each influenza strain), a single EPI vaccination (15μg of each influenza strain) or two adjacent EPI (total of 30μg of each influenza strain). Systemic reactogenicity was similar between control and EPI vaccines. Site reactions following EPI were primarily mild and self-limiting. Seroconversions, titer increases and geometric mean titers to all strains were equivalent or higher in EPI-immunized groups than in controls. Powdered influenza vaccine delivered by EPI is safe and elicits humoral immune responses in humans. [Copyright &y& Elsevier]

Epidermal powder immunization (EPI) of mice with an influenza vaccine elicited consistently a higher hemagglutination inhibition (HI) antibody titers than intramuscular (IM) injection using the same dose of vaccine. The epidermal Langerhans cells (LCs) at the site of EPI were found to play an important role in the immune responses. Indeed, depletion of LCs from the immunization site prior to EPI caused a significant reduction in the antibody response. Transfer of LCs isolated from the EPI sites to naive mice induced a robust antigen-specific antibody response. Cytokines produced by target site cells appear to be important for the augmented immune responses induced by EPI. LTR72, a genetically detoxified heat-labile toxin from Escherichia coli with a strong adjuvant effect in EPI, was found to bind the keratinocytes of the epidermis, but not the LCs, and caused the production of elevated TNF-α and IL-12 cytokines in emigrating epidermal cells. These results have important implications for the development of a more efficacious human influenza vaccine. [Copyright &y& Elsevier]

Antigen presentation is a critical step for the immune system to mount an antigen-specific immune response to invading pathogens. Delivering antigens directly to antigen presenting cells (APCs) is a promising way to improve the immunogenicity and effectiveness of vaccines. Epidermal powder immunization (EPI) delivers vaccine to the epidermis, the superficial layer of skin containing a large number of APCs, and has been shown to elicit augmented antibody responses and cellular immunity to the split influenza vaccine in small animals, nonhuman primates, and humans. EPI is safe and effective and holds promise for future human immunization with influenza and other vaccines. [Copyright &y& Elsevier]

Epidermal powder immunization (EPI) with an influenza vaccine and an adjuvant such as QS-21, LTR72, or cholera toxin elicited augmented serum and mucosal antibody responses in mice. Rhesus macaques, which have an immune system and skin structure similar to humans, were used to further evaluate the immunogenicity of the influenza vaccine following EPI. EPI of rhesus macaques with an influenza vaccine and QS-21 adjuvant elicited significantly higher serum hemagglutination inhibition (HI) titers than antigen alone administered by EPI or by intramuscular (IM) injection using a needle and syringe. In the absence of QS-21, EPI and IM injection elicited comparable HI titers in the monkeys. This study suggests that EPI is a promising technique for administering human vaccine and that QS-21 augments the immunogenicity of co-administered influenza vaccine. [Copyright &y& Elsevier]

The non-toxic B subunit of cholera toxin (CTB) and E. coli heat-labile toxin mutant proteins with reduced toxicity (LTR72) or no toxicity (LTK63) were used as adjuvants for epidermal powder immunization (EPI) with an influenza vaccine. When administered by EPI, CTB, LTR72 and LTK63 significantly augmented antibody responses to the influenza vaccine and protection against a lethal challenge in a mouse model. The antigen dose could be reduced by 125-fold. These adjuvants were well-tolerated both locally and systemically following EPI. These results suggest that EPI with influenza vaccine and a non-toxic bacterial enterotoxin hold promise for human vaccination. [Copyright &y& Elsevier]

Abstract: All vaccines are susceptible to damage by elevated temperatures and many are also damaged by freezing. The distribution, storage, and use of vaccines therefore present challenges that could be reduced by enhanced thermostability, with resulting improvements in vaccine effectiveness. Formulation and processing technologies exist that can improve the stability of vaccines at temperature extremes, however, customization is required for individual vaccines and results are variable. Considerations affecting decisions about stabilization approaches include development cost, manufacturing cost, and the ease of use of the final product. Public sector agencies can incentivize vaccine developers to prioritize stabilization efforts through advocacy and by implementing policies that increase demand for thermostable vaccines. [Copyright &y& Elsevier]

Denitrification is a major process contributing to the removal of nitrogen (N) from ecosystems, but its rate is difficult to quantify. The natural abundance of isotopes can be used to identify the occurrence of denitrification and has recently been used to quantify denitrification rates at the ecosystem level. However, the technique requires an understanding of the isotopic enrichment factor associated with denitrification, which few studies have investigated in forest soils. Here, soils collected from two tropical and two temperate forests in China were incubated under anaerobic or aerobic laboratory conditions for two weeks to determine the N and oxygen (O) isotope enrichment factors during denitrification. We found that at room temperature (20 °C), NO 3 − was reduced at a rate of 0.17 to 0.35 μg N g −1 h −1 , accompanied by the isotope fractionation of N ( 15 ε ) and O ( 18 ε ) of 31‰ to 65‰ (48.3 ± 2.0‰ on average) and 11‰ to 39‰ (18.9 ± 1.7‰ on average), respectively. The N isotope effects were, unexpectedly, much higher than reported in the literature for heterotrophic denitrification (typically ranging from 5‰ to 30‰) and in other environmental settings (e.g., groundwater, marine sediments and agricultural soils). In addition, the ratios of Δδ 18 O:Δδ 15 N ranged from 0.28 to 0.60 (0.38 ± 0.02 on average), which were lower than the canonical ratios of 0.5 to 1 for denitrification reported in other terrestrial and freshwater systems. We suggest that the isotope effects of denitrification for soils may vary greatly among regions and soil types and that gaseous N losses may have been overestimated for terrestrial ecosystems in previous studies in which lower fractionation factors were applied. [ABSTRACT FROM AUTHOR]

Abstract: New vaccine platform and delivery technologies that can have significant positive impacts on the effectiveness, acceptability, and safety of immunizations in developing countries are increasingly available. Although donor support for vaccine technology development is strong, the uptake of proven technologies by the vaccine industry and demand for them by purchasers continues to lag. This article explains the challenges and opportunities associated with accelerating the availability of innovative and beneficial vaccine technologies to meet critical needs in resource-poor settings over the next decade. Progress will require increased dialog between the public and private sectors around vaccine product attributes; establishment of specifications for vaccines that mirror programmatic needs; stronger encouragement of vaccine developers to consider novel technologies early in the product development process; broader facilitation of research and access to technologies through the formation of centers of excellence; the basing of vaccine purchase decisions on immunization systems costs rather than price per dose alone; possible subsidization of early technology adoption costs for vaccine producers that take on the risks of new technologies of importance to the public sector; and the provision of data to purchasers, better enabling them to make informed decisions that take into account the value of specific product attributes. [Copyright &y& Elsevier]

Aluminum-containing adjuvants have been used to enhance the immune response against killed, inactivated, and subunit antigens for more than seven decades. Nevertheless, we are only beginning to gain important insight as to what may be some very fundamental parameters for optimizing their use. For example, there is evidence that the conventional approach of maximizing antigen binding (amount and/or strength) may not result in an optimal immune response. Adsorption of antigen onto the adjuvant has recently been suggested to decrease the thermal stability of some antigens; however, whether adsorption-induced alterations to the structure and/or stability of the antigen have consequences for the elicited immune response is unclear. Finally, the thermal stability of vaccines with aluminum-containing adjuvants is not robust. Optimizing the stability of these vaccines requires an understanding of the freeze sensitivity of the adjuvant, freeze and heat sensitivity of the antigen in the presence of the adjuvant, and perhaps most important, how (or whether) various approaches to formulation can be used to address these instabilities. This review attempts to summarize recent findings regarding issues that may dictate the success of vaccines with aluminum-containing adjuvants. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:388-401, 2011 [ABSTRACT FROM AUTHOR]

Biochar, produced as a by-product of pyrolysis/gasification of waste biomass, shows great potential to reduce the environment impact, address the climate change issue, and establish a circular economy model. Despite the promising outlook, the research on the benefits of biochar remains highly debated. This has been attributed to the heterogeneity of biochar itself, with its inherent physical, chemical and biological properties highly influenced by production variables such as feedstock types and treating conditions. Hence, to enable meaningful comparison of results, establishment of an agreed international standard to govern the production of biochar for specific uses is necessary. In this study, we analyzed four key uses of biochar: 1) in agriculture and horticulture, 2) as construction material, 3) as activated carbon, and 4) in anaerobic digestion. Then the guidelines for the properties of biochar, especially for the concentrations of toxic heavy metals, for its environmental friendly application were proposed in the context of Singapore. The international status of the biochar industry code of practice, feedback from Singapore local industry and government agencies, as well as future perspectives for the biochar industry were explained. Unlabelled Image • Waste to biochar is a sustainable partway to circular economy. • Four key uses of the Singapore biochar industry are analyzed and reviewed. • The code of practice for biochar application in Singapore is proposed. • Future perspective of the research, innovation and development for biochar industry is discussed. [ABSTRACT FROM AUTHOR]

Double mutant heat-labile toxin (dmLT) is a promising adjuvant for oral vaccine administration. The aims of our study were to develop sensitive methods to detect low concentrations of dmLT and to use the assays in preformulation studies to determine whether dmLT remains stable under conditions encountered by an oral vaccine. We developed a sandwich ELISA specific for intact dmLT and a sensitive SDS-PAGE densitometry method, and tested stability of dmLT in glass and plastic containers, in saliva, at the pH of stomach fluid, and in high-osmolarity buffers. The developed ELISA has a quantification range of 62.5 to 0.9 ng/mL and lower limit of detection of 0.3 ng/mL; the limit of quantification of the SDS-PAGE is 10 μg/mL. This work demonstrates the application of dmLT assays in preformulation studies to development of an oral vaccine containing dmLT. Assays reported here will facilitate the understanding and use of dmLT as an adjuvant. [ABSTRACT FROM AUTHOR]

Vaccination is the most effective means of preventing influenza. However, the cost of producing annual seasonal influenza vaccines puts them out of reach for most developing countries. While live attenuated influenza vaccines are among the most efficacious and can be manufactured at low cost, they may require lyophilization to be stable enough for developing-country use, which adds a significant cost burden. The development of a liquid live attenuated seasonal influenza vaccine that is stable for around a year—the duration of an annual influenza season—would significantly improve not only the production output but also the use and accessibility of influenza vaccines in low-resource settings. In this study, potential stabilizing excipients were screened and optimized using the least stable influenza vaccine strain presently known, H1N1 (A/California/07/2009), as a model. The stability-conferring properties of the lead formulations were also tested with a Type B strain of influenza virus (B/Brisbane/60/2008). Stability was also evaluated with higher titers of influenza virus and exposure to agitation and freeze–thaw stresses to further confirm the stability of the lead formulations. Through this process, we identified a liquid formulation consisting of sucrose phosphate glutamate buffer with 1% arginine and 0.5% recombinant human serum albumin that provided storage stability of one year at 2–8 °C for the influenza A and B strains tested. [ABSTRACT FROM AUTHOR]

Rotavirus infection, which can be prevented by vaccination, is responsible for a high burden of acute gastroenteritis disease in children, especially in low-income countries. An appropriate formulation, packaging, and delivery device for oral rotavirus vaccine has the potential to reduce the manufacturing cost of the vaccine and the logistical impact associated with introduction of a new vaccine, simplify the vaccination procedure, and ensure that the vaccine is safely and accurately delivered to children. Single-dose prefilled presentations can be easy to use; however, they are typically more expensive, can be a bottleneck during production, and occupy a greater volume per dose vis-à-vis supply chain storage and medical waste disposal, which is a challenge in low-resource settings. Multi-dose presentations used thus far have other issues, including increased wastage of vaccine and the need for separate delivery devices. In this study, the goals were to evaluate both the technical feasibility of using preservatives to develop a liquid multi-dose formulation and the primary packaging alternatives for orally delivered, liquid rotavirus vaccines. The feasibility evaluation included evaluation of commonly used preservatives for compatibility with rotavirus vaccines and stability testing of rotavirus vaccine in various primary containers, including Lameplast's plastic tubes, BD's oral dispenser version of Uniject™ (Uniject DP), rommelag's blow-fill-seal containers, and MEDInstill's multi-dose vial and pouch. These presentations were compared to a standard glass vial. The results showed that none of the preservatives tested were compatible with a live attenuated rotavirus vaccine because they had a detrimental effect on the viability of the virus. In the presence of preservatives, vaccine virus titers declined to undetectable levels within 1 month. The vaccine formulation without preservatives maintained a stability profile over 12 months in all primary containers that was similar to its profile in standard glass vials. This study demonstrates that there are multiple options for the primary container for rotavirus vaccines intended for oral delivery. Selection of an optimal primary container should take into consideration additional factors, including stability as well as cold chain volume, usability, cost, and manufacturing feasibility. [ABSTRACT FROM AUTHOR]

Tropical rainforest soil is an important source of atmospheric nitrous oxide (N2O). However, there is still considerable uncertainty about the spatial and temporal variability of N2O fluxes. To understand these fluxes, we quantified the annual N2O emissions from three tropical mountain rainforests (primary mountain rainforest, PMR; secondary mountain rainforest, SMR; and Podocarpus imbricatus plantation, PIP) in the Jianfengling National Natural Reserve on Hainan Island, China. The average of N2O emissions in this area was 2.52 ± 0.33 kg N–N2O ha−1 yr−1 (3.52 kg N–N2O ha−1 yr−1 in the wet season and 1.62 kg N–N2O ha−1 yr−1 in the dry season) during our study period, with highly seasonal variations. The mean N2O emission rates were significantly higher during the wet season (68% of the total average) than the dry season (32% of the total average) (P < 0.05). PIP had the highest N2O emission rate at 3.49 ± 0.61 kg N–N2O ha−1 yr−1 (4.74 kg N–N2O ha−1 yr−1 in the wet season and 2.32 kg N–N2O ha−1 yr−1 in the dry season), followed by SMR at 3.03 ± 0.64 kg N–N2O ha−1 yr−1 (4.16 kg N–N2O ha−1 yr−1 in the wet season and 1.97 kg N–N2O ha−1 yr−1 in the dry season), and then PMR at 1.53 ± 0.49 kg N–N2O ha−1 yr−1 (2.21 kg N–N2O ha−1 yr−1 in the wet season and 0.94 kg N–N2O ha−1 yr−1 in the dry season). We observed a significant Gaussian relationship between the N2O fluxes and soil temperature for SMR and PIP but no significant relationship in PMR. There was a significant exponential relationship between the N2O fluxes and water filled pore space (WFPS) in SMR and PIP but not in PMR. [ABSTRACT FROM AUTHOR]

[Display omitted] • A municipal solid waste to energy/resources system was proposed. • The performances of the gasification and dehumidification system were analyzed. • The performance decline of the desiccant coated heat exchanger was evaluated. • Mechanical tests of char-mortar mixtures were conducted. Energy consumption and waste management are two significant challenges for human societies. To realize zero waste management, a pilot-scale demonstration of the conversion of municipal solid waste to energy/resource, which is comprised of a gasification system and a dehumidification air-conditioning to produce heat, cooling, and construction-used char, is investigated and analyzed. The waste heat (60 °C hot water) from a gasification system is applied to drive a dehumidification system for cooling, while the char from the gasification is added to the construction material. The effect of cycle time and air flow rate on the performance of the dehumidification system is also analyzed. The waste to energy efficiency of 57.2%, the maximum average moisture removal of 11.6 g/kg DA , and thermal coefficient of performance of 0.76 are obtained under the climate conditions of 34 °C, 67.5% relative humidity in Singapore. Through comparison between the brand new and used desiccant coated heat exchanger, it is noted that there is a 29.37% decrease of average moisture removal corresponding with a 17.1% loss of thermal coefficient of performance. A 14.6% compressive strength increment after seven days of curing age and 10.3% of compressive strength increment after 28 days are investigated by studying the mechanical behavior of a mortar containing char. [ABSTRACT FROM AUTHOR]

Highlights: [•] FDTs could provide safe and efficient delivery of oral vaccines. [•] Created a formulation containing live attenuated enterotoxigenic E. coli vaccine. [•] Freeze-drying produced a robust, compact FDT with high bacterial viability. [•] FDTs obtained by freeze drying directly in blister sheets can allow efficiency in manufacturing. [•] Vaccines in FDTs will especially be useful in treatment of traveler's diarrhea for travelers to developing countries. [ABSTRACT FROM AUTHOR]

Abstract: There is an unmet medical need for a prophylactic vaccine against herpes simplex virus (HSV). DNA vaccines and cutaneous vaccination have been tried for many applications, but few reports combine this vaccine composition and administration route. We compared DNA administration using the Nanopatch™, a solid microprojection device coated with vaccine comprised of thousands of short (110μm) densly-packed projections (70μm spacing), to standard intramuscular DNA vaccination in a mouse model of vaginal HSV-2 infection. A dose-response relationship was established for immunogenicity and survival in both vaccination routes. Appropriate doses administered by Nanopatch™ were highly immunogenic and enabled mouse survival. Vaginal HSV-2 DNA copy number day 1 post challenge correlated with survival, indicating that vaccine-elicited acquired immune responses can act quickly and locally. Solid, short, densely-packed arrays of microprojections applied to the skin are thus a promising route of administration for DNA vaccines. [ABSTRACT FROM AUTHOR]

Abstract: A combination of unique stabilizers and mild spray drying process conditions was employed to produce heat-stable measles vaccine powder. Live attenuated measles vaccine from Serum Institute of India was formulated with pharmaceutically approved stabilizers, including sugars, proteins, amino acids, polymers, surfactants, and plasticizers, as well as charged ions. In addition, the effects of buffer salt and pH on the storage stability of measles virus were examined. The potency of the dried vaccine stored at several temperatures was quantified by TCID50 assay on Vero cells. As a comparison to other process methods, lead formulations were also subjected to freeze drying and foam drying. The optimized measles vaccine formulation tested at 37°C was stable for approximately 8 weeks (i.e. time for 1logTCID50 loss). The measles titer decreased in a bi-phasic manner, with initial rapid loss within the first week but relative stability thereafter. Key stabilizers identified during the formulation screening processes were l-arginine, human serum albumin, and a combination of divalent cations. Spray drying was identified as the optimal processing method for the preparation of dried vaccine, as it generally resulted in negligible process loss and comparable, if not better storage stability, with respect to the other processes. Processing methods and formulation components were developed that produced a measles vaccine stable for up to 8 weeks at 37°C, which surpassed the WHO requirement for heat stability of 1 week at that temperature. [Copyright &y& Elsevier]

Abstract: Cold chain requirements for vaccine storage and distribution are both economic and logistical burdens for immunization programs, especially those in lower-resource settings. Inadvertent exposure of vaccines to both heat and freezing temperatures within such cold chains are frequently occurring problems in both developing and industrialized countries. Here we report on a new hepatitis B vaccine formulation that is stable against repeated freezing at −20°C and is also stable for 12 months at 37°C. The thermostable vaccine contains all the components of the original vaccine plus 7.5% (v/v) propylene glycol, 40mM phosphate, and 40mM histidine with a final pH of 5.2. The propylene glycol is responsible for the freeze stability while the other components are essential for the heat stability. This formulation was found to be well tolerated in rabbits without any significant local or systemic side effects. The improved stability of this hepatitis B vaccine could be a key factor in ensuring vaccine effectiveness, extending immunization coverage, simplifying immunization logistics, and reducing the costs associated with the cold chain. [Copyright &y& Elsevier]

Abstract: Vaccines containing aluminum salt adjuvants are prone to inactivation following exposure to freeze–thaw stress. Many are also prone to inactivation by heat. Thus, for maximum potency, these vaccines must be maintained at temperatures between 2°C and 8°C which requires the use of the cold chain. Nevertheless, the cold chain is not infallible. Vaccines are subject to freezing during both transport and storage, and frozen vaccines are discarded (under the best circumstances) or inadvertently administered despite potentially reduced potency. Here we describe an approach to minimize our reliance on the proper implementation of the cold chain to protect vaccines from freeze–thaw inactivation. By including PEG 300, propylene glycol, or glycerol in a hepatitis B vaccine, particle agglomeration, changes in the fluorescence emission spectrum – indicative of antigen tertiary structural changes – and losses of in vitro and in vivo indicators of potency were prevented following multiple exposures to −20°C. The effect of propylene glycol was examined in more detail and revealed that even at concentrations too low to prevent freezing at −10°C, −20°C, and −80°C, damage to the vaccine could be prevented. A pilot study using two commercially available diphtheria, tetanus toxoid, and acellular pertussis (DTaP) vaccines suggested that the same stabilizers might protect these vaccines from freeze–thaw agglomeration as well. It remains to be determined if preventing agglomeration of DTaP vaccines preserves their antigenic activity following freeze–thaw events. [Copyright &y& Elsevier]

Abstract: The purpose of this study was to evaluate whether a single peptide containing a major T cell epitope might induce peripheral tolerance in a complex allergen model. C57BL/6 mice were sensitized by intraperitoneal injection of house dust mite extract (HDM), and exposed to antigen via trachea instillation. Der p 1 peptide was administered by i.v. before or after sensitization. Lung lavage fluids were analyzed for cellular infiltration. Respiratory exposure of sensitized mice to antigen results in airway inflammation and eosinophilia. Intravenous administration of a single peptide protected sensitized mice from these changes. Further, the emergence of antigen-specific CD25+CD4+ and IL-10 secreting cell populations in DO11.10 mice was demonstrated after peptide administration. Thus, intravenous delivery of a single peptide epitope is capable of inducing peripheral tolerance and protection in a complex allergy model, possibly through regulatory T cells and bystander suppression. [Copyright &y& Elsevier]

Parenterally administered rotavirus vaccines may overcome the low efficacy observed in resource-poor regions that use live oral formulations. We have reported work on a trivalent nonreplicating rotavirus vaccine (NRRV) for parenteral administration consisting of the recombinant tetanus toxoid P2 CD4 epitope fused to a truncated VP8* fragment (P2-VP8*) for the P[4], P[6], and P[8] serotypes of rotavirus adjuvanted with aluminum. An essential part of developing this vaccine candidate was devising quantification methods for each antigen in the trivalent NRRV in the presence of aluminum adjuvant. This report describes the development of quantitative inhibition enzyme-linked immunosorbent assays (ELISAs) for in vitro antigenicity determination of the adjuvanted trivalent NRRV using serotype-specific monoclonal antibodies (mAbs) against each of the P2-VP8* antigens. Adjuvanted trivalent vaccine samples are titrated and incubated with a constant concentration of specific mAbs against each NRRV P2-VP8* antigen variant. Unbound mAbs are measured by ELISA to indirectly quantify the amount of each antigen present in the trivalent vaccine. Sensitive, specific, and reproducible inhibition ELISAs were developed and qualified for each antigen and used for final product quantification and release testing without desorption of the vaccine antigen. [ABSTRACT FROM AUTHOR]