Injection immunotherapy. British Society for Allergy and Clinical Immunology Working Party.

A working party of the British Society for Allergy and Clinical Immunology has reviewed the role of specific allergen immunotherapy in the treatment of allergic disease and produced a position statement summarising the available evidence for efficacy and safety. The working party recommends specific allergen immunotherapy for treating summer hay fever uncontrolled by conventional medication and for wasp and bee venom hypersensitivity. It is not recommended for asthma or for allergic rhinitis due to other allergens. For the recommended indications the risk:benefit ratio is acceptable provided patients are carefully selected; in particular, patients with asthma should be excluded as they are especially vulnerable to adverse reactions. Injections should be given only by doctors experiences in this form of treatment in a clinic where full resuscitative facilities are immediately available. Provided patients remain symptom free a 60 minute observation period after injection is sufficient to detect all serious adverse reactions.     

Direct and indirect electron transfer between electrodes and redox proteins

The direct electrochemistry of redox proteins has been achieved at a variety of electrodes, including modified gold, pyrolytic graphite and metal oxides. Careful design of electrode surfaces and electrolyte conditions are required for the attainment of rapid and reversible protein-electrode interaction. The electron transfer reactions of more complex systems, such as redox enzymes, are now being examined. The 'well-behaved' electrochemistry of redox proteins can be usefully exploited by coupling the electrode reaction to enzymes for which the redox proteins act as cofactors. In systems where direct electron transfer is very slow, small electron carriers, or mediators, may be employed to enhance the rate of electron exchange with the electrode. The organometallic compound ferrocene and its derivatives have proved particularly effective in this role. A new generation of electrochemical biosensors employs ferrocene derivatives as mediators.     

Eosinophil activation and T lymphocyte infiltration in allergen-induced late phase skin reactions and classical delayed-type hypersensitivity.

T lymphocyte infiltration is a well documented feature of classical delayed-type hypersensitivity (DTH) reactions. Recently, we have shown that T lymphocytes and activated (EG2+) eosinophils accumulate in the allergen-induced late phase skin reaction (LPR). To compare the kinetics and phenotypic composition of these T lymphocyte responses, LPR and DTH reactions of comparable induration size were induced in atopic subjects. In addition, DTH and LPR were compared between atopic and nonatopic subjects. In atopic individuals, allergen challenge elicited a perivascular influx of T lymphocytes that was predominantly CD4+. Eosinophil accumulation and activation were also prominent. There was no cellular response to allergen challenge in the nonatropic group. In both groups, DTH responses showed an intense T cell infiltrate which was more dense and dispersed than in the LPR. CD4+ T cells predominated but at 48 h CD8+ numbers were also significantly increased. In DTH, total leukocyte numbers (CD45+) were increasing at 48 h, whereas in the LPR, cell numbers reached a plateau between 24 and 48 h. T cell activation (shown by expression of IL-2R) was more prominent in DTH. Endothelial expression of HLA-DR was increased in both LPR and DTH, implying the local release of inflammatory cytokines in both reactions. Small but significant numbers of activated eosinophils (EG2+) were detected in atopics and non-atopics at 24 h in DTH but not at 48 h. These findings suggest that the allergen-induced LPR induced in atopic subjects is, at least in part, a form of cell-mediated hypersensitivity but with T cell kinetics that differ from classical DTH.     

Aboveground resource allocation in response to root herbivory as affected by the arbuscular mycorrhizal symbiosis

Aims

Arbuscular mycorrhizal (AM) fungi associate with the majority of terrestrial plants, influencing their growth, nutrient uptake and defence chemistry. Consequently, AM fungi can significantly impact plant-herbivore interactions, yet surprisingly few studies have investigated how AM fungi affect plant responses to root herbivores. This study aimed to investigate how AM fungi affect plant tolerance mechanisms to belowground herbivory.

Methods

We examined how AM fungi affect plant (Saccharum spp. hybrid) growth, nutrient dynamics and secondary chemistry (phenolics) in response to attack from a root-feeding insect (Dermolepida albohirtum).

Results

Root herbivory reduced root mass by almost 27%. In response, plants augmented investment in aboveground biomass by 25%, as well as increasing carbon concentrations. The AM fungi increased aboveground biomass, phosphorus and carbon. Meanwhile, root herbivory increased foliar phenolics by 31% in mycorrhizal plants, and increased arbuscular colonisation of roots by 75% overall. AM fungi also decreased herbivore performance, potentially via increasing root silicon concentrations.

Conclusions

Our results suggest that AM fungi may be able to augment plant tolerance to root herbivory via resource allocation aboveground and, at the same time, enhance plant root resistance by increasing root silicon. The ability of AM fungi to facilitate resource allocation aboveground in this way may be a more widespread strategy for plants to cope with belowground herbivory.

     

Thyme travels: 15N isoscapes of Thymus vulgaris L. invasion in lightly grazed pastoral communities

Alterations to ecosystem nitrogen (N) cycling by introduced plant species may increase the invasibility of habitat providing a positive feedback for the introduced species to become invasive. Spatial patterns of foliar and soil δ¹⁵N ratios reflect variation in rates and process of N‐cycling across invaded landscapes and provide insight into N‐source uptake and utilization strategies of invasive plant species. To evaluate invasion‐associated changes in soil and foliar δ¹⁵N at different scales: regional (among different sites), local (between north‐ and south‐facing aspect at the same site), and microsite (within populations in the same community), we measured foliar and soil δ¹⁵ N, animal faeces cover (as a proxy for grazing intensity) and N₂‐fixing species cover from inside to outside Thymus vulgaris L. (thyme)‐invaded lightly grazed pastoral communities in Central Otago, southern South Island, New Zealand. Mean thyme foliar δ¹⁵N were near‐zero across the invaded landscape, and did not change across the advancing edge of invasion or with aspect. There was no evidence that associations with N₂‐fixing species provide a potential N source. Soil δ¹⁵N was lower inside of thyme compared to at the edge or outside of thyme and was varied between aspects at some sites. Animal faeces cover as a proxy for grazing intensity explained only 23% of this observed variation of soil δ¹⁵N. Thyme invasion may result in lowered soil δ¹⁵N reflecting alterations to N dynamics. Associated invasion‐related impacts of animal grazing may also impact soil δ¹⁵N. Further studies are required to distinguish the underlying mechanism responsible for the observed patterns of foliar and soil δ¹⁵N values across thyme‐invaded Central Otago landscapes.     

pVHL and GSK3beta are components of a primary cilium-maintenance signalling network

Defects in the structure or function of the primary cilium, an antennae-like structure whose functional integrity has been linked to the suppression of uncontrolled kidney epithelial cell proliferation, are a common feature of genetic disorders characterized by kidney cysts. However, the mechanisms by which primary cilia are maintained remain poorly defined. von Hippel-Lindau (VHL) disease is characterized by the development of premalignant renal cysts and arises because of functional inactivation of the VHL tumour suppressor gene product, pVHL. Here, we show that pVHL and glycogen synthase kinase (GSK)3beta are key components of an interlinked signalling pathway that maintains the primary cilium. Although inactivation of either pVHL or GSK3beta alone did not affect cilia maintenance, their combined inactivation leads to loss of cilia. In VHL patients, GSK3beta is subjected to inhibitory phosphorylation in renal cysts, but not in early VHL mutant lesions, and these cysts exhibit reduced frequencies of primary cilia. We propose that pVHL and GSK3beta function together in a ciliary-maintenance signalling network, disruption of which enhances the vulnerability of cells to lose their cilia, thereby promoting cyst formation.