Soya is considered to be one of the eight most significant food allergens. Among the allergenic soya proteins determined to date, P34 has been identified as one of the immunodominant soya antigens. Sensitisation to a specific food antigen like P34 generally follows the transit of intact antigens across the intestinal barrier and usually occurs in infants, who are most susceptible to food allergies. In the present study, we used the intestinal epithelial cell line IPEC-J2, which was originally derived from the jejunum of a neonatal piglet, to recapitulate the infant intestinal epithelium and study the binding and uptake of P34 protein. P34 was partially resistant to degradation in an in vitro proteolysis assay. IPEC-J2 cells were able to endocytose intact P34, as shown by immunofluorescence and immunoelectronmicroscopy methods. P34 associated with lipid raft microdomains of IPEC-J2 cells, and disruption of caveolae/lipid raft microdomains using methyl-β-cyclodextrin abolished P34 endocytosis, indicating that the observed endocytosis was mediated by caveolae. Using IPEC-J2 cells grown on Transwell filters, we further demonstrated that P34 is transported through the epithelial monolayer by transcytosis. Piglets frequently show hypersensitivity to soya antigens, and in this study, we show that healthy adult pigs with dietary exposure to soya protein mount an antibody response to soyabean protein P34, suggesting that this protein has entered the body, probably through gastrointestinal uptake. In summary, our data suggest that soya P34 resists proteolysis in the gastrointestinal tract and is transported through the intestinal epithelial barrier, thereby allowing sensitisation of immune cells in the sub-epithelial compartment.

Nuts are a well-defined cause of food allergy, which affect approximately 1 % of the general population in the UK and the USA. There do appear to be differences in the frequency of nut allergy between different countries because of different dietary habits and cooking procedures. For example, in the USA and France, peanuts are one of the most frequent causes of food allergy, but in other countries, it seems to be less common. Genetic factors, in particular, appear to play a role in the development of peanut allergy. While the majority of nut allergens are seed storage proteins, other nut allergens are profilins and pathogenesis-related protein homologues, considered as panallergens because of their widespread distribution in plants. The presence of specific IgE antibodies to several nuts is a common clinical finding, but the clinical relevance of this cross-reactivity is usually limited. Allergic reactions to nuts appear to be particularly severe, sometimes even life-threatening, and fatal reactions following their ingestion have been documented. Food allergy is diagnosed by identifying an underlying immunological mechanism (i.e. allergic testing), and establishing a causal relationship between food ingestion and symptoms (i.e. oral challenges). In natural history investigations carried out in peanut-allergic children, approximately 20 % of the cases outgrew their allergy or developed oral tolerance. The treatment of nut allergies should include patient and family education about avoiding all presentations of the food and the potential for a severe reaction caused by accidental ingestion. Patients and families should be instructed how to recognise early symptoms of an allergic reaction and how to treat severe anaphylaxis promptly.

Psoroptes ovis, the causative agent of sheep scab, is an important ectoparasitic mite infecting sheep, goats and cattle. Infection is characterized by an extensive dermatitis, scab formation and intense itching. Initial focal lesions spread outwards, coalesce and may extend over the whole body. The host response to infestation has all the characteristics of an immediate-type hypersensitivity reaction but the mite antigens and allergens which initiate this response are almost completely undefined. Here, 507 randomly selected cDNAs derived from a mixed population of P. ovis were sequenced and the resultant nucleotide sequences subjected to Cluster analysis and Blast searches. This analysis yielded 280 clusters of which 49 had >1 sequence with 24 showing significant Blast X homology to another protein in the databases. There were 231 sequences which appeared on one occasion and 109 of these showed significant Blast X homology to other sequences in the databases. This analysis identified homologues of 9 different types of allergens which have been characterized in other allergic conditions such as responses to house dust mites. It also identified a number of cysteine proteases which may contribute to lesion development as well as several free-radical scavenging enzymes which may protect the mite from host immune effector responses.

Five bales were randomly chosen from a stack of 6-month-old barn-stored hay. Four 2·5-kg sections were taken from each bale and subjected to one of four different water wetting treatments, 0-min soak, 10-min soak, 30-min soak and 80-min steaming. Post wetting, the sections were shaken for 9 min under a Negretti LS45F personal dust sampler which sucked-in any particles released into the surrounding air. The sampler contents were then analysed for respirable particle numbers (particles < 5um), and the hay subsampled and analysed for water-soluable carbohydrate, N, Na, K, Ca, P, Mg, Zn, Mn, Fe and Cu. The steaming and soaking treatments all proportionately reduced respirable particle numbers by more than 0·93 of those present in the dry hay. Soaking for 10 min and 30 min significantly reduced levels of P, K, Mg, Na and Cu, whereas the steamed samples showed no loss of nutrients from the levels present in the dry hay. Thus in terms of reducing respirable particle numbers and conserving nutrient levels, steaming for 80 min is the most effective treatment when preparing hay fodder for horses.

Four bales of hay were chosen from a stack of hay, barn-stored for 6 months. Each bale was subdivided into four 2·5 kg sections and one section from each bale was subjected to one of four water soaking treatments: 0, 0·5, 3 or 12 h. Post treatment, the samples were shaken for 9 min under a Negretti LS45F personal dust sampler which sampled the surrounding air. The samples were than analysed for levels of respirable particules < 5 μm in size and for amounts of sodium (Na), potassium (K), phosphorus (P), magnesium (Mg), calcium (Ca) and nitrogen (N). Soaking for 30 min reduced the number of respirable particles by about 90% but also reduced the Na, K and P content of the hay. Soaking for a longer period, at least up to 12 h, did not give a significant further reduction in number of respirable particles but there was loss of Mg and further losses in Na, K, and P. These results clearly indicate that soaking for 30 min is sufficient to reduce the respirable challenge with minimum nutrient loss.