Oral immunotherapy with immunodominant T-cell epitope peptides alleviates allergic reactions in a Balb/c mouse model of egg allergy.

BACKGROUND: Allergen-specific T-cell epitopes are obvious targets for immunotherapeutic interventions in allergic disease. T-cell epitope peptides given orally may provide a practical way of inducing tolerance and preventing allergy. OBJECTIVE: This study investigates oral immunotherapy (OIT) with T-cell epitope peptides of the dominant egg-white allergen ovomucoid (Ovm) in a Balb/c mouse model of egg allergy. METHODS: Groups of mice were orally sensitized to Ovm and subsequently administered Ovm T-cell epitopes [single peptide 157-171 (SP) or multiple peptide (157-171)(3) (MP)], followed by oral challenge with Ovm. Outcomes post oral challenge were measured as clinical signs, serum histamine, antibody activity (IgG, IgE, IgG1, IgG2, IgA), cytokines (IL-4, IFN-γ, IL-12p70, IL-10, TGF-ß, and IL-17), and T regulatory cells (Tregs). RESULTS: Clinical signs were less frequent in both SP and MP groups (P ≤ 0.05). Specific IgE was less and IgA was more in both groups; however, SP-treated mice had less histamine and IgG1 and more IgG2-related antibodies indicating a bias toward the type-1 response (P ≤ 0.05). Concentration of type-2 cytokine interleukin-4 (IL-4) was significantly less in both groups and IL-12p70 and IL-10 were more in SP-treated mice (P ≤ 0.001). Interferon-γ, IL-17, and TGF-ß did not differ significantly. There was significant increase in the percentage of CD4+FOXP3+ and CD4+CD25+ cells in the SP group, indicating the significant role of Tregs in immune regulation. CONCLUSION: In summary, we demonstrated that OIT with SP and MP comprising the immunodominant regions of Ovm was safe and significantly reduced subsequent frequency of allergy to Ovm, and validated potential use of Ovm T-cell epitope as an immunoregulator.

Assessing and treating co-occurring disorders in adolescents: examining typical practice of community-based mental health and substance use treatment providers.

Co-occurring mental health and substance use disorders in adolescents are common. However, limited efforts have been directed at understanding how treatment providers in community settings deal with this frequent challenge. In this study, treatment providers from both substance use and mental health settings were interviewed to examine their common practices regarding the assessment and treatment of co-occurring depression and substance use disorders in adolescence. About 93% of treatment providers reported treating adolescents with these co-occurring conditions. However, few providers reported using formal assessment practices (23-30%) or treatment protocols for co-occurrence (10%). Providers in mental health settings (particularly psychologists) were more likely than those in substance use settings to formally assess for depression [Chi2(1, N = 30) = 3.62, P = .065] but less likely to do so for substance use [Chi2(1, N = 30) = 9.46, P = .004]. Findings are considered with regard to implications for assessment and treatment outcomes in this high-risk population.

Zinc Transporter Protein (tzn-1) May Also Play a Role in Conidiation Pathway of Neurospora crassa: An Insight Using Proteogenomic Approach.

BACKGROUND: Zinc transporter (tzn-1) of Neurospora crassa plays a crucial role in conidiation pathway, as its removal results in aconidiation which was reported in our earlier studies. OBJECTIVES: The main objective of this study was to analyze the role of tzn-1 in conidiation process, by comparing knockout (KO) mutants zinc transporter KO (Δtzn-1) and aconidiating gene KO (Δacon-3) with wild oak ridge (OR) 74 'A' strain by 'Proteo-genomic' approach. METHODS: To identify the commonly expressed protein spots in knockout (KO) mutants zinc transporter KO (Δtzn-1) and aconidiating gene KO (Δacon-3) by comparing with wild oak ridge (OR) 74 'A' strain. Two sets (Δtzn-1 to wild and Δacon-3 to wild) were analyzed by combining 2- Dimensional gel electrophoresis (2DE) with Matrix Associated Laser Desortion/Ionization mass spectrometry -Peptide Mass Fingerprint (MALDI-PMF). Then, the peptide sequences which were obtained by MASCOT (database software) were identified by FGSC BLASTp search analysis. Finally, to evaluate the expression of the KO mutants zinc transporter KO (Δtzn-1) and aconidiating gene KO (Δacon-3) in comparison to wild (OR) 74 'A' type was analyzed by Quantitative Real Time Polymerase Chain Reaction (qRT-PCR) studies. RESULTS: 2DE and MALDI-PMF has shown the nine commonly overexpressed protein spots from the two sets (Δtzn-1 to wild and Δacon-3 to wild). Peptide sequences were obtained by MASCOT (database software) analysis and peptide sequences were identified by FGSC BLASTp search. Eight sequences have shown the similarities with the genes involved during the early stages of conidial and sexual development. Our qRT-PCR analysis has shown that tzn-1 gene was upregulated in contrast to acon-3 gene in absence of iron concentration and down regulated with increase in iron concentrations in wild samples. With increase in zinc supplements, the tzn-1 gene is normally regulated and shown contrasting feature in absence of zinc and acon-3 gene is normally regulated both in presence and absence of zinc. At regular time intervals, declined growth rate was observed after 18hours of induction. CONCLUSION: Thus, we conclude that tzn-1 and acon-3 genes were actively participating in early stages of conidial process and metal ions play some crucial role in the development of the organism.

Proteomic analysis of ovomucoid hypersensitivity in mice by two-dimensional difference gel electrophoresis (2D-DIGE).

There is a need to develop reliable methods to assess the safety of genetically modified and other novel foods. The aim of this study was to identify protein biomarkers of food allergy in mice exposed to ovomucoid (OVM), a major food allergen found in chicken egg white. BALB/c mice were repeatedly sensitized by gavage with OVM and cholera toxin (CT) and control mice were exposed to a mixture of amino acids with CT. At the endpoint, all mice were challenged intraperitoneally with OVM and alum. Type-1 hypersensitivity was confirmed in OVM-sensitized mice by observation of clinical signs of anaphylaxis and elevated levels of plasma histamine, OVM-specific IgE and OVM-specific IgG by ELISA. Differential protein expression was assessed in albumin-depleted plasma as well as in mesenteric lymph node, liver, spleen, and ileum by two-dimensional difference gel electrophoresis (2D-DIGE). Differentially expressed proteins were identified by liquid chromatography with tandem mass spectrometry. Plasma proteins overexpressed in OVM-sensitized mice included haptoglobin (41-fold), serum amyloid A (19-fold) and peroxiredoxin-2 (1.9-fold). Further validation of these plasma proteins in other animal models of food allergy with different food allergens is required to assess their potential as candidate biomarkers for use in evaluating the allergenicity of novel foods.

High-level production and one-step purification of biologically active human growth hormone in Escherichia coli.

A plasmid has been constructed to direct the synthesis of recombinant human growth hormone (re-hGH) in Escherichia coli as a fusion protein containing a His6 tag at the N-terminus under the control of the T5 promoter. The re-hGH was synthesized in large amounts and accumulated in the form of inclusion bodies upon induction with IPTG. Inclusion bodies were solubilized in 6 M guanidine.HCl and the re-hGH was purified by single-step affinity chromatography on Ni(2+)-nitrilotriacetic acid (NTA) agarose. At the shake flask level, the purified re-hGH was obtained with a yield of 30 mg/l of culture. The re-hGH was biologically active in a node rat lymphoma (Nb2) cell bioassay.

Molecular cloning and sequence analysis of bubaline lactoferrin promoter.

The proximal promoter for bubaline lactoferin-encoding gene has been isolated, cloned and sequenced. A 468 bp fragment of the 5' flanking region of the lactoferrin gene was PCR amplified and cloned into pUC18 vector. Sequence analysis of the amplified fragment revealed the presence of one TATA box, one TATA like element, two GC boxes and one motif resembling cAMP response element (CRE) in this region. Bubaline lactoferrin promoter shares 93%, 53%, 52% and 48% homology with cattle, pig, mouse and human lactoferrin 5' flanking region, respectively.

Immune response phenotype induced by controlled immunization of neonatal pigs varies in type 1:type 2 bias.

Immune response (IR) of pigs varies by litter and by individual such that ratios of type-1 and type-2 IR differ. Estimates of heritability for antibody and cell-mediated IR suggest that genotype and the environment contribute approximately 20% and 80% to this variation. It is hypothesized that the IR phenotype of outbred neonatal pigs is immature and variable progressing with age from type-2 bias to a more balanced phenotype. To test this, pigs were IR phenotyped by a standardized protocol using two intramuscular injections of the combined type-1 and type-2 antigens (Ag) Candida albicans (CA) and hen egg white lysozyme (HEWL). Immune response was measured by wheal and flare reaction to HEWL and double skin fold thickness (DSFT) response to each Ag injected intradermally at 35 days of age. Blood was collected at 14 and 35 days of age to measure immunoglobulin IgG(1), IgG(2) and IgE isotype-relatedness of antibody (Ab) to CA and HEWL. Comparison was made between two different groups of pigs (A) and (B), from the same herd tested separately at an interval of two and a half years. An unexpected group difference in IR bias was observed. Bias in IR was not consistently toward type-2. Increase in DSFT to CA, an indicator of type-1 IR, was greater in A while frequency of wheal and flare to injection of HEWL, a type-2 IR correlate, was greater in B. Frequency of individuals with positive serum Ab activity to both Ags was greater in B than A for most isotypes. Ratios of Ab activity by type-1 and 2 isotypes and DSFT to type-1 and 2 Ags indicate diminished type-1 relative to type-2 biased IR response in B. We conclude that in normal neonatal pigs under standard husbandry IR bias is not invariably toward type-2. Phenotype varied between groups in type-1:type-2 bias with implications for protective and immunopathogenic IR. While the etiology was not pursued it is possible that unidentified environmental variables may have induced this change in IR phenotype.

Prophylaxis of experimentally induced ovomucoid allergy in neonatal pigs using Lactococcus lactis.

Probiotic Lactococcus lactis (LL) is immunomodulatory and may prevent allergy by biasing from type-2 to a type-1 immune response. We hypothesized that newborn pigs pre-treated orally with LL are protected against allergy to ovomucoid (Ovm). Pigs were assigned to two treatment groups. Piglets were pretreated orally on days of age 1-7, 10, 12, 14, 21, 28 and 35 with LL (n=30) or medium (control, n=32) and sensitized to Ovm by intraperitoneal injection together with cholera toxin on days 14, 21 and 35. Pigs were orally challenged with egg white (day 46) and assigned scores for allergic signs. Outcomes were measured as direct skin tests, serum antibody to Ovm [IgG (H+L); IgE; IgG(1) and IgG(2)] and cytokine production by mitogen-stimulated blood mononuclear cells (BMC). Clinical signs and skin test positivity were less frequent in the LL group (p ≤ 0.0001). Serum antibody associated with IgG (H and L), IgE, IgG(1) or IgG(2) was significantly increased on day 46 (post-sensitization) compared to day 14 (pre-sensitization) (p ≤ 0.0001). The LL-treated pigs had more IgE and IgG(2)-related antibody activity and lower IgG(1)/IgG(2) and IgE/IgG(2) ratios indicating a type-1 bias in immune response (p ≤ 0.05). Concentration of type-2 cytokines interleukin IL-4 and IL-10 were significantly lower in supernatants of stimulated BMC of LL-treated pigs (p ≤ 0.0001). Interferon-γ, TGF-ß and IL-13 were not detected in control or treated animals. Thus, oral treatment of neonatal pigs with LL significantly reduced subsequent frequency of allergy to Ovm associated with reduced type-2 immune response correlates hence supporting the "hygiene hypothesis" and potential use of LL as a neonatal immunoregulator.

Genetically glycosylated ovomucoid third domain can modulate Immunoglobulin E antibody production and cytokine response in BALB/c mice.

BACKGROUND: Food allergies are on the rise and it is estimated that in North America, 8% of the children and 4% of the adults have food allergies. Food allergies tend to occur more often in children than in adults due to their immature digestive and immune systems. Hen's egg is among the most common cause of food-induced allergic reactions in North America. OBJECTIVE: The present study was undertaken to investigate the role of N-glycans of the third domain of ovomucoid in IgE binding and modulation of allergen-specific immune response in BALB/c mice. METHODS: The cDNA encoding the third domain of ovomucoid was inserted into the yeast genome and expressed in Pichia pastoris X-33 cells, under the control of the glyceraldehyde-3-phosphate (GAP) dehydrogenase promoter for constitutive expression to obtain a post-translationally modified and functionally active ovomucoid third domain. Upon expression, the protein was secreted into the extracellular medium and was purified by size exclusion chromatography. The recombinant protein was produced at 10 mg/L of the culture supernatant. BALB/c mice were sensitized with the recombinant and native forms of glycosylated ovomucoid third domain antigen. The allergic response of the native and the recombinant glycosylated forms of ovomucoid third domain antigens were compared using antibody and cytokine measurements. RESULTS: ELISA tests indicated a significant decrease in specific IgE antibodies to the recombinant N-linked glycosylated form (P-Gly), when compared with the native glycosylated form (DIII+) using mice sera. Immunization with P-Gly induced the production of IFN-gamma [T-helper type 1 (Th1) response] and lowered the production of IL-4 (Th2 response), and a skewed balance towards the Th1 cytokine demonstrated that P-Gly has a modulating ability on Th1/Th2 balance to down-regulate Th2 response. Furthermore, N-linked glycan (N28) in the third domain of ovomucoid was shown to be associated with suppression of the allergic response. CONCLUSION: Therefore, we can conclude that P-Gly facilitates and contributes to the discovery of new molecular target for the development of a safe and specific therapeutic vaccine for the treatment of egg allergy, and oligosaccharides do seem to play a major role in the suppression of IgE-binding activity.

Engineered recombinant ovomucoid third domain can desensitize Balb/c mice of egg allergy.

The purpose of this study was to determine the in vivo desensitization efficacy of a hypoallergenic variant of egg white ovomucoid third domain (DIII) in Balb/c mice model. We mapped the immunodominant B-cell epitopes of ovomucoid in Balb/c mice. A hypoallergenic ovomucoid third domain (GMFA) mutant isoform having ablated allergenicity against egg allergic patient's sera was used to desensitize DIII-sensitized Balb/c mice by intraperitoneal injections. Ovomucoid DIII generated high levels of plasma histamine and specific immunoglobulin (Ig)E levels, and increased Th2 type cytokine (IL-4). On the other hand, the allergic response of mice desensitized with the GMFA was found to be significantly inhibited and abrogated by prevention of anaphylaxis reactions, low histamine levels and increased Th1-type cytokine (INF-gamma). It was found that significantly higher levels of IL-10 and IL-12 were secreted in the desensitized group. Desensitization with the GMFA antigen also suppressed synthesis of DIII specific-IgE levels and enhanced specific IgG2a and IgG levels compared with the group treated with the DIII antigen. The present results indicated that hyposensitization with the GMFA can desensitize or down-regulate the allergic response in Balb/c mice and this hypoallergenic variant of ovomucoid DIII can shift an ongoing allergen-specific Th2 response towards a Th1 skewed response.

Ablation of ovomucoid-induced allergic response by desensitization with recombinant ovomucoid third domain in a murine model.

Attempts to modulate the allergenic response by hypoallergens aimed at eliminating IgE-binding epitopes have been established recently for allergen immunotherapy. Desensitization offers an alternative approach to mounting a protective immune response. We have shown previously that mutation of the decisive amino acids in the B cell epitope of the ovomucoid third domain suppresses IgE binding reactivity against human patient sera and we hypothesize that this hypoallergenic variant could be a potential candidate molecule for specific immunotherapy against an ovomucoid-induced IgE reaction. The aim of this study was to investigate whether hyposensitization with the ovomucoid-modified isoform could desensitize ovomucoid-sensitized mice. We mapped the immunodominant B cell epitopes of ovomucoid in Balb/c mice. A hypoallergenic ovomucoid mutant isoform, having ablated allergenicity against patient sera, was used to desensitize ovomucoid-sensitized Balb/c mice by intraperitoneal injection. Female Balb/c mice were sensitized with intact ovomucoid molecule (Fovm) and desensitized with the modified isoform of the third domain of ovomucoid (GMFA). Intact ovomucoid-sensitized mice desensitized with phosphate-buffered saline (PBS) served as positive controls to maintain hypersensitivity. To gain insight into the efficacy of the modified ovomucoid variant in desensitization, effects on hypersensitivity reactions and histamine levels, followed by its association with antibody levels and cytokine profiles, were measured. Abrogation of the allergic response with complete suppression of anaphylactic symptoms and lower serum histamine levels was observed in the desensitized group by GMFA, accompanied by significantly reduced ovomucoid-specific IgE and IgG1 levels and enhanced specific IgG and IgG2a levels. The sensitized group showed severe anaphylactic symptoms, enhanced serum histamine concentrations and increased levels of specific IgE and IgG1. The level of interleukin (IL)-4 was decreased dramatically in the desensitized group and higher levels of interferon (IFN)-gamma were found, whereas mice sensitized with intact ovomucoid exhibited significantly higher levels of IL-4 favouring a Th2 skewed pathway. We demonstrate clearly that GMFA is able to ablate ovomucoid-induced allergic reactions in sensitized mice. This occurs via a suppression of specific IgE accompanied by an increase in suppressor T cell activity. This approach offers some promise for the development of treatment against ovomucoid-induced allergic response.

Molecular cloning of Clostridium perfringens epsilon-toxin gene and its high level expression in E. coli.

A gene coding for epsilon-toxin was isolated from a field isolate of Clostridium perfringens type D by PCR amplification and was cloned under the control of T5 promoter fused with six-histidine tag at the amino terminal end. Escherichia coli cells harbouring this construct expressed high levels of the recombinant protein in the form of inclusion bodies. The protein was purified using single step affinity chromatography on a Ni(2+)-nitrilotriacetic acid (NTA) agarose column. Upon immunization of rabbit with the purified recombinant protein, high antibody titre was detected. The antibodies raised against the recombinant protein were able to recognize the recombinant as well as the native toxin. Anti epsilon-toxin monoclonal antibody was able to detect the recombinant protein in a Western blot. N-terminal sequence of the recombinant protein matched with the known sequence of the toxin. At the shake flask level, up to 20 mg of pure epsilon-prototoxin was produced per litre of culture.