Evaluation on two types of paramyosin vaccines for the control of Haemaphysalis longicornis infestations in rabbits.

BACKGROUND: Haemaphysalis longicornis is an obligate hematophagous ectoparasite that transmits a variety of pathogens causing life-threatening diseases in humans and animals. Paramyosin (Pmy) is not only an invertebrate-specific myofibrillar protein but also an important immunomodulatory protein. Therefore, it is one of the ideal candidate antigens for vaccines. METHODS: We conducted two vaccine trials to evaluate the protective efficacy of Pmy recombinant protein (rPmy) and peptide vaccine (KLH-LEE). Each rabbit was immunized with three doses of rPmy or KLH-LEE adjuvanted with Freund's complete/incomplete at 500 µg/dose at 2-week intervals before challenge with 40 female H. longicornis/rabbit. PBS plus adjuvant, Trx or KLH was used as control group. The antibodies of rabbits were detected by ELISA. Then, female ticks were fed on the rabbits until detachment. RESULTS: ELISA results showed that both vaccines induced rabbits to produce antibodies. Compared with the Trx group, the engorgement weight, oviposition and hatchability of the rPmy group decreased by 8.87%, 26.83% and 38.86%, respectively. On the other hand, engorgement weight, oviposition and hatchability of female ticks in the KLH-LEE group correspondingly resulted in 27.03%, 53.15% and 38.40% reduction compared with that of the KLH group. Considering the cumulative effect of vaccination on the evaluated parameters, results showed 60.37% efficacy of the rPmy vaccine formulation and 70.86% efficacy in the KLH-LEE group. CONCLUSIONS: Pmy and particularly epitope LEE have potential for further development of an effective candidate vaccine to protect the host against tick infection. GRAPHIC ABSTARCT.

Tectochrysin ameliorates murine allergic airway inflammation by suppressing Th2 response and oxidative stress.

Tectochrysin, a flavonoid compound, can be isolated from propolis, Alpinia oxyphylla Miq, and Lychnophora markgravii. This study evaluated the efficacy of tectochrysin in the treatment of shrimp tropomyosin (ST)-induced mouse asthma. Mice were sensitized with intraperitoneal (i.p.) injection of ST together with aluminum hydroxide as an adjuvant to establish a mouse model of asthma. Mice were i.p.-treated daily with tectochrysin. IgE levels in plasma, Th2 cytokines from both bronchoalveolar lavage (BAL) fluid and splenocytes, and CD200R on basophils in peripheral blood were measured. Histological analyses of lung tissues and accumulation of leukocytes in BAL fluid were performed. Lung eosinophil peroxidase, catalase and glutathione peroxidase activities were examined. ST was found to markedly increase eosinophilic inflammation and Th2 response in mice. Tectochrysin treatment reduced the level of IgE in plasma, the percentage of eosinophils in total white blood cells in peripheral blood, the total number of cells in BAL fluid, and eosinophil peroxidase activity in lung tissues. Tectochrysin attenuated ST-induced infiltration of eosinophils and epithelial mucus secretion in lung tissues and suppressed the overproduction of Th2 cytokines (IL-4 and IL-5) in BAL fluid. Tectochrysin also attenuated Th2 cytokine (IL-4 and IL-5) production from antigen-stimulated murine splenocytes in vitro, decreased the expression of CD200R on basophils in peripheral blood of asthmatic mice and inhibited IL-4 secretion from IgE-sensitized RBL-2H3 cells. In addition, tectochrysin enhanced catalase and glutathione peroxidase activities in lung tissues. Our findings demonstrate that TEC ameliorates allergic airway inflammation by suppressing Th2 response and oxidative stress.

Shrimp allergy: beyond avoidance diet.

SUMMARY: Currently, the management of people diagnosed with shellfish allergy relies on the avoidance of those foods. HDM immunotherapy has been reported to induce both shrimp allergy in non-allergic patients, and shrimp tolerance in shrimp-allergic patients. This article summarizes therapeutic options other than avoidance diet for shrimp allergic patients available once the diagnostic is established, such as production of hypoallergenic shrimp, use of immunotherapy with modified allergens, probiotics and Chinese herbal formulations.

Vaccination with recombinant paramyosin in Montanide ISA206 protects against Schistosoma japonicum infection in water buffalo.

BACKGROUND: Schistosomiasis japonica is a zoonosis and presents significant public health problems in China and the Philippines. Vaccines targeting domestic animals constitute attractive control measures. METHODS: We conducted three vaccine trials to evaluate the protective efficacy of recombinant full-length paramyosin (rSj97) in water buffalo. Animals were immunized with 3 doses of rSj97 adjuvanted with ISA206 at 250µg/dose or 500µg/dose at 4wk intervals before challenge with 1000 Schistosoma japonicum cercariae. The primary outcome was worm burden assessed by portal perfusion 8-10weeks post challenge. Safety measures included weight, temperature, body condition score, hemogram and routine assays for hepatic and renal function. RESULTS: The three-dose regimen was well tolerated in all three trials. In the first trial, vaccinated buffalo had 51.5% lower worm burden post challenge compared to controls. In the second trial, buffalo immunized with 500µg/dose of rSj97 had 57.8% lower worm burden compared to controls (p=0.026). A similar but not significant reduction (60.9%) was observed with animals administered with 250ug rSj97/dose. In the third trial, buffalo immunized with a 500µg/dose of rSj97 had 57.8% lower worm burden compared to controls (p=0.014). CONCLUSIONS: These findings indicated that rSj97 is a safe and promising vaccine candidate for schistosomiasis japonica in water buffalo.

How relevant is panallergen sensitization in the development of allergies?

Panallergens comprise various protein families of plant as well as animal origin and are responsible for wide IgE cross-reactivity between related and unrelated allergenic sources. Such cross-reactivities include reactions between various pollen sources, pollen and plant-derived foods as well as invertebrate-derived inhalants and foodstuff. Here, we provide an overview on the most clinically relevant panallergens from plants (profilins, polcalcins, non-specific lipid transfer proteins, pathogenesis-related protein family 10 members) and on the prominent animal-derived panallergen family, tropomyosins. In addition, we explore the role of panallergens in the sensitization process and progress of the allergic disease. Emphasis is given on epidemiological aspects of panallergen sensitization and clinical manifestations. Finally, the issues related to diagnosis and therapy of patients sensitized to panallergens are outlined, and the use of panallergens as predictors for cross-reactive allergy and as biomarkers for disease severity is discussed.

Sarcoplasmic calcium-binding protein: identification as a new allergen of the black tiger shrimp Penaeus monodon.

BACKGROUND: Tropomyosin and arginine kinase have been identified as crustacean allergens. During purification of arginine kinase from black tiger shrimp Penaeus monodon, we found a new allergen of 20-kDa. METHODS: A 20-kDa allergen was purified from the abdominal muscle of black tiger shrimp by salting-out, anion-exchange HPLC and reverse-phase HPLC. Following digestion of the 20-kDa allergen with lysyl endopeptidase, peptide fragments were isolated by reverse-phase HPLC, and 2 of them were sequenced. The 20-kDa allergen, together with tropomyosin and arginine kinase purified from black tiger shrimp, was evaluated for IgE reactivity by ELISA. Five species of crustaceans (kuruma shrimp, American lobster, pink shrimp, king crab and snow crab) were surveyed for the 20-kDa allergen by immunoblotting. RESULTS: The 20-kDa allergen was purified from black tiger shrimp and identified as a sarcoplasmic calcium-binding protein (SCP) based on the determined amino acid sequences of 2 enzymatic fragments. Of 16 sera from crustacean-allergic patients, 8 and 13 reacted to SCP and tropomyosin, respectively; the reactivity to arginine kinase was weakly recognized with 10 sera. In immunoblotting, an IgE-reactive 20-kDa protein was also detected in kuruma shrimp, American lobster and pink shrimp but not in 2 species of crab. Preadsorption of the sera with black tiger shrimp SCP abolished the IgE reactivity of the 20-kDa protein, suggesting the 20-kDa protein to be an SCP. CONCLUSIONS: SCP is a new crustacean allergen, and distribution of IgE-reactive SCP is probably limited to shrimp and crayfish.

Ulcerative colitis after autologous peripheral blood stem cell transplantation for non-Hodgkin's lymphoma.

A 54-year-old woman with peripheral T cell lymphoma in second complete remission (CR) received an autologous peripheral blood stem cell transplant (PBSCT). Antibiotic-resistant bloody diarrhea, and fever developed 110 days after transplant. Blood and stool cultures were negative. Skin rash was not observed. Barium enema and colonoscopy showed typical features of pancolonic-type ulcerative colitis (UC). Endoscopic biopsies confirmed the diagnosis of UC. Mesalazine and immunosuppressive therapy improved symptoms dramatically. We detected serum antibodies against synthetic tropomyosin (TM) peptide when UC was diagnosed. We postulate that autoimmunity including autoreactive anti-TM antibodies may be involved in the pathogenesis of UC after autologous PBSCT in this patient.

Identification and molecular characterization of Charybdis feriatus tropomyosin, the major crab allergen.

BACKGROUND: Crab sensitivity is one of the most common seafood allergies. However, to date, there has been no report on the molecular characterization of crab allergens and no comparative analysis with other seafood allergens. OBJECTIVE: This study was undertaken to clone, identify, and determine the primary structure of a major IgE-reactive molecule in crab. METHODS: We constructed an expression cDNA library from a common crab, Charybdis feriatus. This library was then screened with the use of sera from subjects with a well-documented history of type I hypersensitivity reactions upon ingestion of crab. An IgE-reactive clone was chosen and subcloned into plasmids for nucleotide sequence determination and expression in Escherichia coli. RESULTS: We identified a 1-kb cDNA designated as Cha f 1. Expression of Cha f 1 produces a 34-kd recombinant protein reactive to the IgE antibodies from patients with crab allergies but not from control subjects. Cha f 1 has an opening reading frame of 264 amino acids and demonstrates marked homology to the shrimp tropomyosin Met e 1. Absorption of allergic sera with Cha f I removes IgE reactivity to crab extract. Moreover, absorption of allergic sera with recombinant shrimp Met e 1 tropomyosin removes IgE reactivity to Cha f 1. CONCLUSIONS: This 34-kd protein, designated as Cha f 1, is the first identified major allergen of crab. Nucleotide and amino acid comparison shows that this protein is the crab tropomyosin. The molecular basis of shrimp and crab allergy is readily demonstrated at the nucleotide and amino acid level.

Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen.

Crustaceans are a major cause of seafood allergy. Recent studies have identified tropomyosin as the major allergen in shrimp. However, such data are lacking in other crustaceans. In the present study lobster allergens were identified and characterized by molecular cloning, sequencing, and expression. An IgE-reactive complementary DNA clone of 2 kilobase pairs (kb) was identified by screening an expression library of the spiny lobster Panulirus stimpsoni using sera from subjects with crustacean allergy. Expression and sequencing of this clone showed that it has an opening reading frame of 274 amino acids, coding for a 34-kDa protein designated as Pan s I. In addition, we expressed the fast muscle tropomyosin from the American lobster Homarus americanus and found that this protein, coined Hom a I, was also recognized by IgE from patients with crustacean allergies. The deduced amino acid sequences of Pan s I and Hom a I, which are the first identified lobster allergens, show significant homology to shrimp tropomyosin. Sera from subjects with crustacean allergies, when preabsorbed with recombinant proteins Pan s I or Hom a I, lost their IgE reactivity to muscle extract of P. stimpsoni and H. americanus. Preincubation of crustacean allergy sera with the recombinant shrimp tropomyosin Met e I also removed their IgE reactivity to lobster muscle extracts. The results suggest that patients with allergic reactions to crustaceans have common and possibly cross-reactive IgE-reactive epitopes in lobster and shrimp.

Quantification of the major brown shrimp allergen Pen a 1 (tropomyosin) by a monoclonal antibody-based sandwich ELISA.

BACKGROUND: Among 13 allergens found in extracts of cooked brown shrimp (Penaeus aztecus) the 36 kd muscle protein tropomyosin has been identified as the only major shrimp allergen (Pen a 1). Cross-reacting molecules with similar molecular weights were detected in other crustacea species such as crab, lobster, and crawfish. Because Pen a 1 and Pen a 1-like allergens are important in crustacea allergy, the aim of this study was to develop a monoclonal antibody (mAb)-based sandwich ELISA to quantify Pen a 1 and to evaluate Pen a 1 levels in four commercial shrimp, crab, and lobster extracts. METHODS: Two Pen a 1-specific mAbs with different epitope specificities were selected. ELISA plates coated with captured mAb 3.2 were incubated with samples containing Pen a 1. Bound Pen a 1 was detected by a combination of biotinylated mAb 4.9.5 and alkaline phosphatase-labeled streptavidin. RESULTS: The optimized sandwich ELISA could detect Pen a 1 concentrations ranging from 4 to 125 ng/ml. Four commercial shrimp extracts demonstrated a 40-fold difference in Pen a 1 levels (24 to 920 microg/ml). Crab and lobster extracts contained detectable levels of Pen a 1-like proteins. No reactivity to cockroach, house dust mite, oyster, codfish, or peanut extracts was detected, which indicates that the developed assay is crustacea-specific. CONCLUSION: A sensitive sandwich assay was developed to quantify Pen a 1. This assay will be helpful to standardize shrimp extracts in regard to the content of the major allergen, Pen a 1, and to study cross-reactivities among and evaluate occupational exposure to different crustacea species.