Oscar L. Frick

Thioredoxin treatment increases digestibility and lowers allergenicity of milk

BACKGROUND By resisting digestion in the stomach, the major bovine milk allergen, beta-lactoglobulin, is believed to act as a transporter of vitamin A and retinol to the intestines. beta-Lactoglobulin has 2 intramolecular disulfide bonds that may be responsible for its allergic effects. OBJECTIVE This study was carried out to assess the importance of disulfide bonds to the allergenicity and digestibility of beta-lactoglobulin. METHODS beta-Lactoglobulin was subjected to reduction by the ubiquitous protein thioredoxin, which was itself reduced by the reduced form of nicotinamide adenine dinucleotide phosphate by means of nicotinamide adenine dinucleotide phosphate-thioredoxin reductase. Digestibility was measured with a simulated gastric fluid; results were analyzed by SDS-PAGE. Allergenicity was assessed with an inbred colony of high IgE-producing dogs sensitized to milk. RESULTS As found for other proteins with intramolecular disulfide bonds, beta-lactoglobulin was reduced specifically by the thioredoxin system. After reduction of one or both of its disulfide bonds, beta-lactoglobulin became strikingly sensitive to pepsin and lost allergenicity as determined by skin test responses and gastrointestinal symptoms in the dog model. CONCLUSION The results provide new evidence that thioredoxin can be applied to enhance digestibility and lower allergenicity of food proteins.

Allergen immunotherapy with heat-killed Listeria monocytogenes alleviates peanut and food-induced anaphylaxis in dogs

Background:  Heat‐killed Listeria monocytogenes (HKL) potently stimulates interferon (IFN)‐γ production in CD4 T‐lymphocytes, and when used as adjuvant for immunotherapy, reduces immunoglobulin (Ig)E production and reverses established allergen‐induced airway hyperreactivity (AHR) in a murine model of asthma. We asked if such treatment could decrease established peanut‐induced anaphylaxis or cows milk‐induced food allergy in highly food‐allergic dogs.

Effect of respiratory and other virus infections on IgE immunoregulation

An association between respiratory infections and subsequent development of asthma was noted by Hippocrates.’ He also recognized the hereditary nature of asthma, which was confirmed formally first by Cooke and VanderVeer’ and later by others. Asthma was classified into extrinsic (allergic) and intrinsic (infectious) forms by Rackemand; this has been a useful working hypothesis, although we now recognize the inflammatory nature of chronic asthma. Clinicians have known for years that respiratory tract infections often precede asthma attacks. In young children (younger than 5 years) before and during asthma attacks, respiratory syncytial virus and parainfluenza infections were documented by direct isolation or rising antibody titers in 41% of subjects in the classic study by McIntosh et al4 In older children and adults, Minor et a1.5 found that rhinoviruses and influenza were commonly implicated in asthmatic episodes.

The Dog as a Model for Food Allergy

Abstract: Research during the past decade has shown the dog to be an excellent model for human food allergies. Humans and dogs share many of the same allergies to foods. Furthermore, the dog model shows clinical symptoms typical of humans, that is, both experience vomiting and diarrhea. Present results suggest that the dog may provide a means to test genetically modified foods for unsuspected allergens.

The Level of Expression of Thioredoxin is Linked to Fundamental Properties and Applications of Wheat Seeds

Work with cereals (barley and wheat) and a legume (Medicago truncatula) has established thioredoxin h (Trx h) as a central regulatory protein of seeds. Trx h acts by reducing disulfide (S-S) groups of diverse seed proteins (storage proteins, enzymes, and enzyme inhibitors), thereby facilitating germination. Early in vitro protein studies were complemented with experiments in which barley seeds with Trx h overexpressed in the endosperm showed accelerated germination and early or enhanced expression of associated enzymes (alpha-amylase and pullulanase). The current study extends the transgenic work to wheat. Two approaches were followed to alter the expression of Trx h genes in the endosperm: (1) a hordein promoter and its protein body targeting sequence led to overexpression of Trx h5, and (2) an antisense construct of Trx h9 resulted in cytosolic underexpression of that gene (Arabidopsis designation). Underexpression of Trx h9 led to effects opposite to those observed for overexpression Trx h5 in barley-retardation of germination and delayed or reduced expression of associated enzymes. Similar enzyme changes were observed in developing seeds. The wheat lines with underexpressed Trx showed delayed preharvest sprouting when grown in the greenhouse or field without a decrease in final yield. Wheat with overexpressed Trx h5 showed changes commensurate with earlier in vitro work: increased solubility of disulfide proteins and lower allergenicity of the gliadin fraction. The results are further evidence that the level of Trx h in cereal endosperm determines fundamental properties as well as potential applications of the seed.

Distinctive patterns of release of neuroendocrine peptides after nasal challenge of allergic subjects with ryegrass antigen.

The concentrations of the neuropeptides substance P, somatostatin, and calcitonin gene-related peptide in human nasal secretions were quantified by radioimmunoassays, concurrently with that of histamine, in the course of nasal challenge of allergic and control subjects with ryegrass antigen to examine contributions of neuromediation of the tissue response. Each of theneuropeptides and histamine were detected in nasal lavage fluid prior to challenge. In allergic patients, but not normal controls, antigen evoked significant increases of 3-fold in histamine at 15–60 min, 1.5- to 4-fold in calcitonin gene-related peptide at 15 min-24 hr, and more than 2-fold in somatostatin at 6 hr, without altering the concentration of substance P in nasal lavage fluid. The identity of the neuropeptides was confirmed chromatographically. Thus calcitonin gene-related peptide may mediate nasal congestion directly and somatostatin may be one of the factors regulating the late involvement of basophils and mast cells in allergic rhinitis.

Neuropeptides, mast cells and allergy: novel mechanisms and therapeutic possibilities

Diverse neuropeptides are released by neuroendocrine and immune cells at the sites of allergic and inflammatory reactions. The neuropeptides and other neuromediators affect functions of smooth muscle, microvasculature and secretory cells, and are potent stimuli of mast cell, lymphocyte and other leucocyte contributions to such reactions. The distinctive immune sources, structures and cellular receptors for neuromediators suggest the possibility of novel pathogenetic mechanisms and levels of pharmacological intervention specific for neuroregulation of immunity and hypersensitivity.

An immunological approach to the diagnosis of food sensitivity

Nineteen patients with delayed onset food sensitivity were compared with fourteen patients with immediate reactions and twenty‐one non‐atopic subjects in terms of clinical symptoms, foods involved and IgE mediated immunological reactions. The immediate reactors were frequently positive to all tests used: skin tests (71%), allergen induced leucocyte histamine release (71%), radioimmunodiffusion (55%) and skin window (55%). Those with the delayed onset variety were seldom positive by skin testing (13%), or skin window (0%), while 39% were positive by leucocyte histamine release and 48% demonstrated specific IgE food antibodies. Control subjects had negative responses to immunological tests for IgE antibody except for leucocyte histamine release (24%). Reasons for the differences between immediate and delayed onset food sensitivity in clinical symptoms, foods involved and immunologic parameters are discussed. A careful history in conjunction with the elimination and challenge technique remains the most useful tool at present for the delayed onset group. In vitro methods for detecting specific IgE responses may also prove to be helpful.

Leukocyte inhibition factor in delayed-onset food allergy

To investigate the possiblity of a cellular immune hypersensitivity reaction in patients who developed allergic symptoms 2 or more hours after ingestion of a particular food, two in vitro tests were employed: leukocyte migration inhibition factor (LIF) and lymphoblastogenesis. Of the children and adults with food allergy, 73% (30 of 41) had a positive LIF test with whole cows milk or its fractions or corn. Of nonallergic or grass-pollen sensitive controls, 15% (four of 26) had positive LIF. Lymphocyte transformation often correlated with LIF results in food-allergic patients but was also positive in 77% of controls (seven of nine). We suggest that many patients with delayed-onset food-induced allergy symptoms may have a cellular immune component to their sensitivity. Serum IgA, where measured, was absent or low in half of these patients.

Cutaneous allergic response in atopic dogs: Relationship of cellular and histamine responses

We studied the cutaneous response to intradermal antigen using clinical, histologic, and physiologic criteria in ragweed-sensitized dogs. The clinical response was measured early (the wheal at 20 minutes) and late (induration at 6 hours). We assessed cutaneous responsiveness to histamine before and 6 hours after injection (intradermally) of ragweed (n = 5, antigen group) and diluent (n = 4, 10% glycerin in 0.9% NaCl, sham group); we measured the wheal in response to histamine (1.0 ng to 0.1 mg, intradermally), constructed a dose-response curve, and interpolated the provocative dose (milligrams) of histamine required to create a wheal 10 mm larger than the response to saline control. Skin biopsy specimens were obtained before and after injection of either ragweed or diluent. Consistent with the human late-phase response, neutrophils and eosinophils were present in the dermis at 1 hour, maximal at 6 hours, and decreased at 24 hours. Mononuclear cells increased significantly at 6 hours and were the predominant cells present at 24 hours after antigen. The late clinical response correlated only with influx of eosinophils (rs = 0.85; p less than 0.005). Histamine responsiveness increased markedly after antigen (p less than 0.0001), did not change after glycerin diluent (sham), and was correlated with the intensity of neutrophil influx at 6 hours (rs = 0.69; p less than 0.05), and to a much greater degree with mononuclear cell influx at 6 hours (rs = 0.85; p less than 0.005).