Field evaluation of candidate baits for oral delivery of BCG vaccine to European badgers,Meles meles

The control of tuberculosis (TB) in cattle in the UK and Ireland is compromised by transmission of Mycobacterium bovis to cattle from the European badger (Meles meles), which acts as a wildlife reservoir. Vaccination of badgers could potentially contribute to TB control but the only licensed vaccine is injectable BadgerBCG which requires the live-capture of badgers. Current research is aimed at developing an oral TB vaccine (where vaccine is contained within bait) that is intended to be more cost-effective to deploy over large areas. In order to identify a lead product, candidate baits identified from captive badger studies were evaluated in three successive bait screening studies with wild badgers. A fourth field study, using the lead candidate bait and biomarkers, investigated the effectiveness of different carriers for their potential to deliver liquid payloads (vaccine surrogate). In each field study, bait disappearance was monitored daily for ten days and remote video surveillance was used to determine preference (i.e. the order in which baits were taken). In the carrier study, biomarkers were used to determine what proportion of subsequently trapped badgers had ingested the bait and the vaccine-carrier biomarker payload. Across all four studies, 79% (3397/4330) of baits were taken by badgers although the number varied significantly by badger social group and bait type. In all studies, bait disappearance increased over time, with 75–100% of baits being taken by day ten. In the carrier study, 75% (9/12) of trapped badgers tested positive for at least one of the biomarkers and the type of carrier did not influence bait attractiveness. Together with data from complementary laboratory and captive animal studies, this study identified a highly attractive and palatable bait (peanut-based paste bait; PT) and vaccine-carrier (hydrogenated peanut oil; HPO) combination with the potential to deliver a liquid vaccine to wild badgers.     

Tamoxifen Attenuates Lipopolysaccharide/Galactosamine-induced Acute Liver Failure by Antagonizing Hepatic Inflammation and Apoptosis

Bacterial lipopolysaccharide (LPS)-induced acute liver failure (ALF) is a common severe clinical syndrome in intensive care unit. No other methods are available for its prevention apart from supportive treatment and liver transplantation. Tamoxifen (TAM) was reported to attenuate ALF induced by excessive acetaminophen, while its effect on LPS-induced ALF remained unknown. For this, in the present study, we comprehensively assessed whether TAM can attenuate ALF induced by LPS/galactosamine (GaIN). Mice were given TAM once a day for three times. Twelve hours after the last treatment, mice were given LPS/GaIN (intraperitoneally [i.p.]). Survival, plasma transaminases, and histopathology were examined. Serum TNF-α and IL-1β were analyzed by ELISA. Hepatic apoptosis was analyzed by TUNEL and caspase-3 Western blotting, respectively. Compared to the model group, ALF induced by LPS/GaIN was alleviated remarkably following TAM administration, as evidenced by the improvement of survival (87.5% vs. 37.5%), hepatic swell, moderate transaminases, slightly increased serum TNF-α, IL-1β (P < 0.05), and moderate histopathology. In respect of apoptosis, severe hepatocellular apoptosis was reduced notably by TAM treatment confirmed by less TUNEL-positive hepatocytes and decreased caspase-3 cleavage. The results demonstrated that TAM could attenuate LPS/GaIN-induced ALF effectively, probably due to hepatic inflammation and apoptosis antagonism. Furthermore, it was the first report about the effect of TAM on LPS/GaIN-induced ALF.     

Single Dose Parenteral Hyposensitization to Poison Ivy Urushiol in Guinea Pigs

Abstract

Studies were carried out in guinea pigs to evaluate the potential for single dose hyposensitization to poison ivy urushiol dermatitis. Sensitization was induced by topical application of lmg of poison ivy urushiol to the back of the neck. In the first series of studies, three different analogs of poison ivy urushiol were studied: 1) a mixture of penta-decyl and heptadecyl catechols (PDC/HDC), the saturated side chain analog of the natural urushiol mixture; 2) a mixture of the diacetate esters of PDC and HDC (PDC/HDC Ac), the esterified form of the saturated sidechain analogs; 3) 2-n-pentadecyl hydroquinone diacetate (HQ Ac). Each of these compounds was administered as 5 mg of the free catechol i.m. each week for three weeks. A vehicle group received only corn oil injections. Reactivity to poison ivy urushiol (PIU) challenge was evaluated in skin tests at 1 and 5 weeks post-treatment PDC/HDC Ac induced a marked reduction in both the incidence and the severity of lesions induced by PIU at both 1 and at 5 weeks post-treatment. Other analogs were ineffective at 5 weeks post-treatment, and were less effective than PDC/HDC Ac at 1 week post-treatment In a second series of experiments, the efficacy of PDC/HDC Ac was evaluated in both single and multiple dose regiments. One treatment group received 5 mg of PDC/HDC Ac intramuscularly each week for 4 weeks, while another treatment group received a single dose of 20 mg PDC/HDC Ac i.m. Corresponding vehicle control groups were also included. At 1 week post-treatment in the single dose group, the PDC/HDC Ac was only modestly effective, with some reduction of severity of lesions at the higher challenge doses of PIU. However, at 4 and 7 weeks post-treatment, both the incidence and the severity of the lesions at all challenge doses were reduced. In the multiple dose group, the incidence and severity of lesions are reduced at 1 week and 4 weeks post-treatment (4 weeks and 7 weeks after the initial dose) but were not significandy different from the single dose group. These findings indicate that the diacetate ester of PDC/HDC is an effective hyposensitizer to poison ivy urushiol, and that this hyposensitization can be reasonably accomplished in a single dose treatment regimen.     

The cationic amphiphile 3,4-bis(tetradecyloxy)benzylamine inhibits LPS signaling by competing with endotoxin for CD14 binding

The identification of the bacterial endotoxin receptors for innate immunity, most notably the Toll-like receptor 4 (TLR4), has sparked great interest in therapeutic manipulation of innate immune system. We have recently developed synthetic molecules that have been shown to inhibit TLR4 activation in vitro and in vivo. Here we present the synthesis and the biological characterization of a new molecule, the cationic amphiphile 3,4-bis(tetradecyloxy)benzylamine, with a structure strictly related to the previously developed TLR4 modulators. This compound is able to inhibit in a dose-dependent manner the LPS-stimulated TLR4 activation in HEK cells. In order to characterize the mechanism of action of this compound, we investigated possible interactions with the extracellular components that bind and shuttle LPS to TLR4, namely LBP, CD14, and MD-2. This compound inhibited LBP/CD14-dependent LPS transfer to MD-2.TLR4, resulting in reduced formation of a (LPS-MD-2-TLR4)₂ complex. This effect was due to inhibition of the transfer of LPS from aggregates in solution to sCD14 with little or no effect on LPS shuttling from LPS/CD14 to MD-2. This compound also inhibited transfer of LPS monomer from full-length CD14 to a truncated, polyhistidine tagged CD14. Taken together, our findings strongly suggest that this compound inhibits LPS-stimulated TLR4 activation by competitively occupying CD14 and thereby reducing the delivery of activating endotoxin to MD-2.TLR4.     

Stabilizing effects of calcium alginate microspheres on mycobacterium bovis BCG intended for oral vaccination

In this study, alginate microspheres containing BCG were prepared at a diameter of ～10?µm by emulsification–internal gelation of an alginate–BCG solution dispersed in olive oil using a high rate speed stirrer. The stability of BCG was assayed at 4°C showing that the encapsulated BCG was more stable than free BCG at least for 5 weeks; however, BCG in sodium alginate solution was not stable at all. On the other hand, the studies using media with different pH (1.2, 4.4, 6.2, 6.8 and 7.5) have demonstrated that the alginate microspheres are stable in acidic medium for upto 1.5?h without any sign of disintegration. Moreover, BCG incorporated in alginate microspheres demonstrated an almost 9-fold increase in viable bacilli in simulated gastric fluid (SGF) after 1.5?h in comparison with free BCG.     

Reprint of “The developing oligodendrocyte: key cellular target in brain injury in the premature infant”

Brain injury in the premature infant, a problem of enormous importance, is associated with a high risk of neurodevelopmental disability. The major type of injury involves cerebral white matter and the principal cellular target is the developing oligodendrocyte. The specific phase of the oligodendroglial lineage affected has been defined from study of both human brain and experimental models. This premyelinating cell (pre-OL) is vulnerable because of a series of maturation-dependent events. The pathogenesis of pre-OL injury relates to operation of two upstream mechanisms, hypoxia-ischemia and systemic infection/inflammation, both of which are common occurrences in premature infants. The focus of this review and of our research over the past 15–20 years has been the cellular and molecular bases for the maturation-dependent vulnerability of the pre-OL to the action of the two upstream mechanisms. Three downstream mechanisms have been identified, i.e., microglial activation, excitotoxicity and free radical attack. The work in both experimental models and human brain has identified a remarkable confluence of maturation-dependent factors that render the pre-OL so exquisitely vulnerable to these downstream mechanisms. Most importantly, elucidation of these factors has led to delineation of a series of potential therapeutic interventions, which in experimental models show marked protective properties. The critical next step, i.e., clinical trials in the living infant, is now on the horizon.     

血吸虫重组BCG疫苗的研究进展

卡介苗(BCG)由于其安伞性及免疫佐剂作用而被广泛应用,以其为载体的重组疫苗研究日益受到研究者的重视.血吸虫重组BCG疫苗是一种新型疫苗.该文简要概述了近年米曼氏血吸虫、埃及血吸虫、日本血吸虫重组BCG疫苗的构建及免疫机制的研究进展.