Application of commercial kits using DNA-based and immunochemical methods for determination of shrimp allergens in kimchi and its ingredients.

Shrimps cause a significant part of crustacea-related allergies. It is used in processed foods, including fermented Korean foods, such as kimchi. Even low amounts of shrimp allergens can provoke reactions in consumers allergic to shrimp. Accurate food labeling is the most effective means of preventing the consumption of allergenic ingredients. To validate labeling compliance and minimize the risk of cross-contaminations, the effectiveness of methodologies used for the detection of allergens in foods should be compared. Here, seven commercial kits, based on quantitative real-time polymerase chain reaction (PCR) or enzyme-linked immunosorbent assay (ELISA), were assessed for their ability to detect the presence of shrimp allergens in food. Our results showed that SureFood real-time PCR kit and Ridascreen ELISA kit had the highest recovery, whereas five other kits underperformed in the determination of allergen content of kimchi and its ingredients. The variation in recovery among the kits depended on the limit of detection and reactivity to the shrimp allergens, tropomyosin, and sarcoplasmic calcium-binding protein. PRACTICAL APPLICATION: This research confirms the performance of commercial kits to detect the presence of shrimp allergens in kimchi, and demonstrates that the sensitivity of these kits depends on reactivity to the specific shrimp allergenic proteins. These results can be used to food allergy labeling and can be applied by the food industry to develop allergen test kits for fermented foods with improved performance.

Improvement of innate immune responses and defense activity in mitten crab (Eriocheir sinensis) by oral administration of beta-glucan.

The beta-glucan (BG), extracted from Saccharomyces cerevisiae cell wall, was orally administrated to the mitten crab (Eriocheir sinensis) at 0, 1, 5 and 10 g BG/kg diet for 28 days, followed by a challenge with Vibrio mimicus by intramuscular injection. Growth, phenoloxidase, superoxide dismutase, acid phosphatase and alkaline phosphatase activity were monitored after 14 and 28 days. The results showed an immunomodulatory effect and protection against V. mimicus by dietary supplementation of BG. The recommended concentration is 5 g BG/kg diet.

Protein profiling of hemocytes from the terrestrial crustacean Armadillidium vulgare.

To establish and maintain a successful infection, microbial pathogens have evolved various strategies to infect the host in the face of a functional immune system. In this context, the alpha-proteobacteria Wolbachia capacities to infect new host species have been greatly evidenced. Indeed, in terrestrial isopods, experimentally transferred Wolbachia invade all host tissues, including immune cells such as hemocytes. To investigate mechanisms that have to be avoided by bacteria to maintain themselves in hemocytes, we characterized the hemocyte proteome of Armadillidium vulgare by a 2D gel electrophoresis approach. Fifty-six proteins were identified and classified into functional groups (stress and immunity, glucose metabolisms, cytoskeleton, others). We focused on immune response and cytoskeleton proteins often exploited by bacteria to invade their host. From the microsequences obtained by mass spectrometry, PCR primers were designed to amplify seven partial cDNAs encoding masquerade, alpha2-macroglobulin, transglutaminase, MnSOD, calreticulin, cyclophilin, and vinculin, confirming their expression in hemocytes.

Cross-reactivity of foods--mechanisms and clinical significance.

We have been most fortunate to witness advances in techniques related to the field of allergy. The development and implementation of RAST, RAST inhibition, crossed immunoelectrophoresis, and CRIE have allowed us to determine what food moieties have the potential to be allergenic. Furthermore, using the above techniques, it has become possible to delineate whether allergenic moieties in particular food stuffs share their allergenic determinants with other food materials. Despite these advances, it is difficult to make definite statements concerning clinically significant cross-reactivity among nuts, legumes, and crustacea. There is still, obviously, a role for the use of open and double-blind food challenges, as demonstrated by the peanut oil, soybean oil, and sunflower oil studies. Although food challenges, in situations where anaphylaxis is a possibility, should only be done under controlled circumstances and under the guidance of a well-defined protocol, this technique should remain available to further study cross-reactivity among foods. At the present time, the following conclusions concerning cross-reactivity among foods may be entertained. (1) Cross-reactivity among foods from different food groups is extremely rare. (2) Individuals having IgE-mediated reactions to legume proteins, for example peanut and soybean, do not respond to the corresponding oil derived from those substances. (3) Cross-reactivity among legumes may occur, but in vitro studies defining common allergenic determinants among these food substances cannot be automatically interpreted as reflecting in vivo cross-reactivity. Furthermore, very limited attempts at open and double-blind challenges in specific patients have not confirmed cross-reactivity in peanut-sensitive individuals to other legumes.(ABSTRACT TRUNCATED AT 250 WORDS)

Crawfish and lobster allergens: identification and structural similarities with other crustacea.

Antigenic and allergenic components in crawfish and lobster extracts were studied using crossed immunoelectrophoretic techniques. Crossed immunoelectrophoresis with rabbit antisera revealed 23 antigens in crawfish and 17 antigens in lobster extracts. Both extracts exhibited structural similarities in antigens mutually and with other crustacea in cross-line immunoelectrophoresis. Crossed radioimmunoelectrophoresis (CRIE) demonstrated 6 crawfish and 4 lobster allergens when individual or pooled sera from radioallergosorbent test (RAST)-positive crustacea-sensitive subjects were used. Since radiostaining was also observed with sera from RAST-negative nonsensitive subjects, specificity of IgE binding was tested using CRIE-inhibition. Preincubation of RAST-positive sera with crawfish or lobster extract decreased radiostaining in CRIE, while no changes occurred when using control sera. These results confirmed the presence of IgE-mediated mechanisms in seafood allergy and demonstrated a number of shared antigenic determinants among crustacea allergens.