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D Kraft

Publications and source records attributed to D Kraft.

At least 19 recordsLinked to original sources
PubMed2000

[Hydroxyethyl starch accumulation in the skin with special reference to hydroxyethyl starch-associated pruritus].

BACKGROUND AND OBJECTIVE: Hydroxyethyl starch (HES) is a colloidal infusion fluid that has for a long time been used in emergency situations and to improve impaired blood perfusion. In the last few years there have been numerous reports about treatment resistant pruritus, often persisting for months, after HES infusion. We investigated the intracellular uptake of HES in the skin, special attention being focused on associated pruritus. PATIENTS AND METHODS: Skin biopsies were obtained from 120 patients (120 men, 35 women) and examined immunohistochemically and for their ultrastructure. Three patients had received various HES preparations, while 22 had been given dextran. Five patients who had received no infusions served as controls. RESULTS: All patients given HES had lysosomal deposits in the histiocytes, some of them also in cutaneous epithelium and endothelium. The extent of lysosomal storage correlated with the amount of infused HES and the interval between biopsy and last HES infusion. Consecutive biopsies in some cases demonstrated a definite decrease over the years of HES deposits in the vacuoles. This suggests that HES is regularly metabolized in the skin. Pruritus after high cumulative doses of HES was closely correlated with HES deposition in cutaneous nerves. CONCLUSIONS: These results emphasize the need for starch derivatives that can be better metabolized and for better adapted infusion schedules to reduce the high incidence of pruritus.

Adolescent↗
PubMed2000

Molecular characterization of human IgG monoclonal antibodies specific for the major birch pollen allergen Bet v 1. Anti-allergen IgG can enhance the anaphylactic reaction.

We report the molecular characterization of five human monoclonal antibodies, BAB1-5 (BAB1: IgG(1); BAB4: IgG(2); BAB2, 3, 5: IgG(4)), with specificity for the major birch pollen allergen, Bet v 1. BAB1-5 were obtained after immunotherapy and contained a high degree of somatic mutations indicative of an antigen-driven affinity maturation process. While BAB1 inhibited the binding of patients IgE to Bet v 1, BAB2 increased IgE recognition of Bet v 1, and, even as Escherichia coli-expressed Fab, augmented Bet v 1-induced immediate type skin reactions. The demonstration that IgG antibodies can enhance allergen-induced allergic reactions is likely to explain the unpredictability of specific immunotherapy.

Allergens↗
PubMed2000

Quantitative IgE inhibition experiments with purified recombinant allergens indicate pollen-derived allergens as the sensitizing agents responsible for many forms of plant food allergy.

BACKGROUND: Type I allergic symptoms in the oropharyngeal mucosa upon contact with plant-derived food in patients with pollen allergies have been termed oral allergy syndrome (OAS). IgE cross-reactivity between pollen and food allergens represents the molecular basis for this phenomenon. The sensitizing allergen source (pollen or plant food) in OAS is a controversial issue. OBJECTIVE: We sought to determine the primary sensitizing molecules in patients with OAS. METHODS: We used recombinant birch pollen (rBet v 1 and rBet v 2) and plant food allergens (apple, rMal d 1; celery, rApi g 1; and carrot, rDau c 1), as well as natural pollen (birch and timothy grass) and plant food (apple, peach, kiwi, hazelnut, celery, and carrot) allergens, to identify cross-reactive allergens by using qualitative immunoblot inhibitions. In addition, we determined the percentage of plant food-specific IgE that can be preadsorbed with recombinant and natural pollen allergens by quantitative RAST inhibitions by using sera from 71 patients with OAS. RESULTS: Preincubation of sera with recombinant and natural pollen allergens led to an almost complete inhibition of IgE binding to plant food allergens in Western blots, as well as in RAST inhibition experiments. In contrast, recombinant plant food allergens poorly inhibited IgE binding to Bet v 1. CONCLUSION: Most IgE epitopes in plant food recognized by patients with OAS are resembled by pollen allergens. Thus pollen allergens may be responsible for the elicitation and maintenance of OAS.

Adult↗
PubMed2000

Prevention of latex allergy by selection of low-allergen gloves.

BACKGROUND: In recent years the prevalence of type I allergy to latex has continuously increased, in particular among healthcare workers, to about 10%. While most forms of type I allergy caused by other environmental allergens can be treated by pharmacotherapy or specific immunotherapy, minimizing exposure to latex proteins may represent an effective preventive measure for latex allergy. OBJECTIVE: To investigate whether it is possible to select by in vitro and in vivo testing low-allergen latex gloves for prevention of latex allergy. METHODS: We obtained separate extracts by standard aqueous extraction from the inner and outer surfaces of 15 different commonly used (10 examination, five surgical) glove brands. The extracts were analysed by quantitative (bicinchoninic protein assay, immunoglobulin [Ig] E-ELISA, ELISA competition) and qualitative (SDS-PAGE, silver staining, IgE immunoblotting) methods for their protein and allergen contents. In addition, the glove extracts were analysed for their capacity to induce basophil histamine release and immediate skin reactions. RESULTS: Extracts from different glove brands contained cross-reactive IgE epitopes. However, IgE binding studies, basophil histamine release and skin testing showed that different glove brands and their inner and outer surfaces contained widely varying protein and allergen contents. While the determination of total protein contents was not sufficient to identify low-allergen gloves, IgE measurements, basophil histamine release and skin testing were in good agreement and allowed to select low-allergen products. CONCLUSION: We suggest the use of low-allergen latex products identified by IgE binding, basophil histamine release assays and skin testing as a feasible preventive measure for latex allergy.

Adolescent↗
PubMed2000

Mutual boosting effects of sensitization with timothy grass pollen and latex glove extract on IgE antibody responses in a mouse model.

Type I allergy to natural rubber latex can be an important health problem for latex-exposed individuals (e.g., health care workers, spina bifida children). Also beyond these risk groups, a high sensitization rate of varying and partly unknown clinical relevance has been reported. Atopy represents a risk factor for latex allergy and recent studies indicate that patients suffering from pollen allergies may have pollen allergen-specific IgE antibodies which cross-react with latex allergens. In order to investigate whether sensitization to pollen allergens can have priming effects on the production of IgE antibodies against latex in vivo, a mouse model was established. Groups of 10 BALB/C mice were immunized with Al(OH)3-adsorbed pollen extracts from timothy grass, ragweed, mugwort, or birch. For control purposes, one additional group received adjuvant only and another group was not immunized. Half of the mice of each group were subsequently immunized with Al(OH)3-adsorbed latex glove extract, the other half with adjuvant only. Pollen and latex-specific IgE- and IgG1-antibody responses were analyzed by enzyme-linked immunosorbent assay and statistically evaluated by analysis of variance. Antibody responses to cross-reactive antigens were investigated by immunoblotting. We found significantly increased IgE reactivities to latex after pollen sensitization and vice versa. Moreover, mice immunized with timothy grass pollen extract alone - without subsequent latex immunization - displayed IgE reactivity to latex. Cross-reactive antibodies were directed against pollen antigens of approximately 60 kDa molecular weight. Our results thus demonstrate a mutual boosting effect of pollen and latex sensitization in vivo which may be also operative in polysensitized plant allergic patients.

Allergens↗
PubMed2000

Dissociation of allergen-specific IgE and IgA responses in sera and tears of pollen-allergic patients: a study performed with purified recombinant pollen allergens.

BACKGROUND: Trees and grass pollen allergens represent potent elicitors of allergic rhinoconjunctivitis and asthma. Little is known regarding the presence of allergen-specific IgA antibodies in sera and tears and their association with IgE responses in patients with allergic conjunctivitis. OBJECTIVE: The purpose of this study was to compare the specificities of IgE and IgA antibodies in sera and tears of pollen-allergic patients with conjunctivitis by using purified recombinant pollen allergens. METHODS: Sera and tears collected from 23 pollen-allergic and from 23 nonatopic individuals were analyzed for IgE and IgA reactivity to nitrocellulose-blotted birch and timothy grass pollen extracts. In addition, we determined the specificities of IgE, IgG(1-4), and IgA antibodies with use of a panel of purified recombinant pollen allergens (timothy grass: rPhl p 1, rPhl p 2, rPhl p 5; birch: rBet v 1, rBet v 2) in serum and tear samples by immunoblotting and ELISA. Statistical analyses of data were performed by t test and Mann Whitney U test. RESULTS: Serum and tears of many of the pollen-allergic individuals with conjunctivitis exhibited specificity for the very same pollen allergens. No allergen-specific IgE antibodies were detected in tears of nonatopic individuals. IgA antibodies in sera and tears of patients with allergic conjunctivitis were mainly directed against nonallergenic moieties and showed specificities that were significantly different from those of IgE antibodies. CONCLUSION: The dissociation of IgE and IgA responses and the lack of allergen-specific IgA antibodies in mucosal secretions (eg, tears) may contribute to allergic manifestations in target organs of atopy. Induction of allergen-specific IgA antibodies may hence be considered as a promising strategy for the treatment of mucosal forms of atopy.

Allergens↗
PubMed2000

Engineering, purification and applications of His-tagged recombinant antibody fragments with specificity for the major birch pollen allergen, bet v1.

Type I allergy, an immunodisorder affecting almost 20% of the population worldwide, is based on the production of IgE antibodies against per se harmless allergens. We report the expression of hexahistidine-tagged antibody fragments (Fabs) with specificity for Bet v1, the major birch pollen allergen, in Escherichia coli. The cDNA coding for the heavy chain fragment of a mouse monoclonal anti-Bet v1 antibody, Bip 1, was engineered by PCR to contain a hexahistidine-encoding 3' end. The modified Bip1 heavy chain cDNA was co-expressed in E. coli XL-1 Blue with the Bip 1 light chain cDNA using the combinatorial plasmid pComb3H. His-tagged recombinant (r) Bip 1 Fabs were isolated by nickel affinity chromatography and rBip 1 Fabs without His-tag were purified via affinity to rBet v1. rBip 1 Fabs with and without His-tag bound specifically to rBet v1 and, like Bet v1 -specific human serum IgE and rabbit-anti rBet v1 antibodies, cross-reacted with Bet v1-related allergens in other plant-species (alder, oak, hazelnut). We demonstrate the usefulness of His-tagged rBip 1 Fabs (1) for the identification of pollen samples containing Bet v 1 by particle blotting, (2) forthe detection of Bet v1-specific IgE antibodies in human serum samples by sandwich ELISA and (3) for the quantification of Bet v1 in solution. Based on these examples we suggest to use rBip 1 Fabs for the detection of Bet v1 and Bet v1-related allergens in natural allergen sources for allergy prevention, as well as for the standardization of natural allergen extracts produced for diagnosis and immunotherapy of birch pollen allergy.

Allergens↗
PubMed1999

Molecular, immunological, and structural characterization of Phl p 6, a major allergen and P-particle-associated protein from Timothy grass (Phleum pratense) pollen.

Due to the wide distribution and heavy pollen production of grasses, approximately 50% of allergic patients are sensitized against grass pollen allergens. cDNAs coding for two isoforms and four fragments of a major timothy grass (Phleum pratense) pollen allergen, Phl p 6, were isolated by IgE immunoscreening from a pollen expression cDNA library. Recombinant Phl p 6 (rPhl p 6), an acidic protein of 11.8 kDa, was purified to homogeneity as assessed by mass spectrometry and exhibited almost exclusive alpha-helical secondary structure as determined by circular dichroism spectroscopy. Phl p 6 reacted with serum IgE from 75% of grass pollen-allergic patients (n = 171). IgE binding experiments with rPhl p 6 fragments indicated that the N terminus of the allergen is required for IgE recognition. Purified rPhl p 6 elicited dose-dependent basophil histamine release and immediate type skin reactions in patients allergic to grass pollen. A rabbit antiserum raised against purified rPhl p 6 identified it as a pollen-specific protein that, by immunogold electron microscopy, was localized on the polysaccharide-containing wall-precursor bodies (P-particles). The association of Phl p 6 with P-particles may facilitate its intrusion into the deeper airways and thus be responsible for the high prevalence of IgE recognition of Phl p 6. Recombinant native-like Phl p 6 can be used for in vitro as well as in vivo diagnoses of grass pollen allergy, whereas N-terminal deletion mutants with reduced IgE binding capacity may represent candidates for immunotherapy of grass pollen allergy with a low risk of anaphylactic side effects.

Air Pollutants↗
PubMed1999

Treatment of atypical depression with cognitive therapy or phenelzine: a double-blind, placebo-controlled trial.

BACKGROUND: Patients with atypical depression are more likely to respond to monoamine oxidase inhibitors than to tricyclic antidepressants. They are frequently offered psychotherapy in the absence of controlled tests. There are no prospective, randomized, controlled trials, to our knowledge, of psychotherapy for atypical depression or of cognitive therapy compared with a monoamine oxidase inhibitor. Since there is only 1 placebo-controlled trial of cognitive therapy, this trial fills a gap in the literature on psychotherapy for depression. METHODS: Outpatients with DSM-III-R major depressive disorder and atypical features (N = 108) were treated in a 10-week, double-blind, randomized, controlled trial comparing acute-phase cognitive therapy or clinical management plus either phenelzine sulfate or placebo. Atypical features were defined as reactive mood plus at least 2 additional symptoms: hypersomnia, hyperphagia, leaden paralysis, or lifetime sensitivity to rejection. RESULTS: With the use of an intention-to-treat strategy, the response rates (21-item Hamilton Rating Scale for Depression score, < or =9) were significantly greater after cognitive therapy (58%) and phenelzine (58%) than after pill placebo (28%). Phenelzine and cognitive therapy also reduced symptoms significantly more than placebo according to contrasts after a repeated-measures analysis of covariance and random regression with the use of the blind evaluator's final Hamilton Rating Scale for Depression score. The scores between cognitive therapy and phenelzine did not differ significantly. Supplemental analyses of other symptom severity measures confirm the finding. CONCLUSIONS: Cognitive therapy may offer an effective alternative to standard acute-phase treatment with a monoamine oxidase inhibitor for outpatients with major depressive disorder and atypical features.

Adult↗
PubMed1999

Induction of antibody responses to new B cell epitopes indicates vaccination character of allergen immunotherapy.

Whether the modulation of antibody responses can contribute to the improvement of clinical symptoms in patients receiving allergen immunotherapy represents a controversial issue. We have used purified [seven recombinant (r) and one natural] timothy grass pollen allergens as well as recombinant B cell epitope-containing fragments of the major timothy grass pollen allergen, Phl p 1, to investigate humoral immune responses in eight allergic patients receiving grass pollen-specific immunotherapy. We found that the administration of aluminium hydroxide-adsorbed grass pollen extract induced complex changes in allergen/epitope-specific antibody responses: increases in IgG subclass (IgG1, IgG2, IgG4) responses against allergens recognized before the therapy were observed. All eight patients started to mount IgE and IgG4 responses to continuous Phl p 1 epitopes not recognized before the therapy and a de novo induction of IgE antibodies against new allergens was found in one patient. Evidence for a protective role of IgG antibodies specific for continuous Phl p 1 epitopes was provided by the demonstration that preincubation of rPhl p 1 with human serum containing therapy-induced Phl p 1-specific IgG inhibited rPhl p 1-induced histamine release from basophils of a grass pollen-allergic patient. Our finding that immunotherapy induced antibody responses against previously not recognized B cell epitopes indicates the vaccination character of this treatment. The fact that patients started to mount de novo IgE as well as protective IgG responses against epitopes may explain the unpredictability of specific immunotherapy performed with allergen extracts and emphasizes the need for novel forms of component-resolved immunotherapy.

Adult↗
PubMed1999

Oligodeoxynucleotides containing CpG motifs induce IL-12, IL-18 and IFN-gamma production in cells from allergic individuals and inhibit IgE synthesis in vitro.

The effects of phosphorothioate oligonucleotides containing CpG motifs (CpG-ODN) on cultured cells from allergic patients and non-atopic individuals were investigated. In peripheral blood mononuclear cells (PBMC) CpG-ODN led to a significant increase of IFN-gamma. By intracellular cytokine staining, IFN-gamma production could be attributed to NK cells and inhibition experiments indicated an IL-12-dependent mechanism. Moreover, CpG-ODN increased mRNA expression of IL-12 and IL-18 in PBMC. In this respect, no significant difference between allergic and non-atopic individuals was observed. Monocyte-derived dendritic cells were identified as one IL-12- and IL-18-producing source. In addition, stimulation of PBMC derived from atopic patients with CpG-ODN led to a considerable increase of polyclonal IgG and IgM synthesis. In contrast, the production of total IgE was suppressed. CpG-ODN induced a significant rise of IgG and IgM specific for allergens to which the patients were sensitized, whereas allergen-specific IgE levels remained unchanged. Our data suggest that CpG-ODN display a strong influence on the ongoing immune response and might represent potential adjuvants for specific immunotherapy of type I allergy.

Base Sequence↗
PubMed1999

Oligodeoxynucleotides containing CpG motifs modulate the allergic TH2 response of BALB/c mice to Bet v 1, the major birch pollen allergen.

BACKGROUND: The use of adequate adjuvants to modulate the allergic T(H2)-type immune response is a promising concept for future immunotherapy of type I allergy. Bacterial DNA or oligodeoxynucleotides containing CpG motifs (CpG-ODNs) have been demonstrated to foster T(H1)-type immune responses. OBJECTIVE: We investigated the adjuvanticity of CpG-ODNs and their capability to modulate the allergic T(H2) response in a mouse model. METHODS: BALB/c mice were treated with CpG-ODNs and Bet v 1, the major birch pollen allergen, in different experimental setups. Allergen-specific antibody responses, T(H) cytokines, and eosinophilic infiltration of the airways were investigated. RESULTS: Intraperitoneal administration of Bet v 1 together with aluminium hydroxide led to a typical T(H2) response. In contrast, coadminstration of CpG-ODNs with Bet v 1 in aluminium hydroxide resulted in markedly increased T(H1) activities (high IgG2a levels) and subsequently to reduced airway inflammation. The T(H1)-like immune response indicated by these humoral findings was also reflected by decreased IL-5 and increased IFN-gamma levels in cell cultures. CpG-ODNs as sole adjuvants with Bet v 1 did not lead to measureable Ig responses after subcutaneous or intraperitoneal immunizations; after intranasal application, 3 of 10 mice reacted. Nevertheless, a prophylactic effect was obtained with all routes tested; that is, mice treated subsequently with an established aerosol sensitization protocol displayed altered immune responses characterized by drastically elevated levels of Bet v 1-specific IgG2a, indicating a T(H1)/T(H0)-like immunity. Application of CpG-ODNs after aerosol sensitization also induced IgG2a. CONCLUSION: By inducing T(H1)/T(H0)-biased immune responses to allergens, the use of CpG-ODNs as adjuvants may have important impacts for new forms of specific immunotherapy in type I hypersensitivity.

Adjuvants, Immunologic↗
PubMed1999

Suppression of antigen-specific T- and B-cell responses by intranasal or oral administration of recombinant bet v 1, the major birch pollen allergen, in a murine model of type I allergy.

BACKGROUND: Mucosal (nasal or oral) administration of soluble protein antigens induces a state of antigen-specific immunologic hyporesponsiveness. Several studies have shown that induction of mucosal tolerance can prevent the onset or reduce the severity of certain TH1 -mediated experimental autoimmune diseases. Only a few studies describe similar results for type I allergies, which are caused by excessive TH2 cell activities. OBJECTIVE: We sought to investigate whether mucosal tolerance induction would also be efficient in preventing an allergic type I immune response. METHODS: A murine model of inhalative type I allergy, leading to sensitization to birch pollen and its major allergen Bet v 1 in BALB/c mice, was used. Recombinant Bet v 1 was nasally or orally applied in low doses before sensitization. At the time of death, immediate-type skin tests were performed. Blood was taken, and serum was used for measurement of allergen-specific antibodies. Spleen cell cultures were performed to determine cytokine production (IL-4, IL-5, IL-10, and IFN-gamma), as well as levels of TGF-beta mRNA. RESULTS: Both nasal and oral administration of minimal doses of recombinant Bet v 1 before aerosol sensitization with birch pollen suppressed the allergen-specific antibody production of all isotypes. Consequently, the in vivo type I skin test responses to the allergen were negative in the tolerized, in contrast to the sensitized, group. Moreover, allergen-specific lymphoproliferative responses and cytokine production in vitro (ie, IFN-gamma, IL-4, IL-5, and IL-10) were markedly reduced. In contrast, expression of TGF-beta mRNA was markedly increased in spleen cells from nasally tolerized animals, indicating regulatory mechanisms for tolerance induction. CONCLUSION: We conclude from the present study that nasal, as well as oral, administration of recombinant allergen is an effective way to prevent allergen-specific T- and B-cell responses in a TH2 model.

Administration, Intranasal↗
PubMed1999

Serological characterization of allergens in poppy seeds.

BACKGROUND AND OBJECTIVE: Poppy seeds in food can induce immediate-type allergic reactions ranging from mild local symptoms to severe anaphylactic reactions. Previous publications showed that poppy seeds cross-react with other plant-derived allergens. The IgE-binding components have not been defined so far. METHODS: We analysed sera from 11 patients with adverse reactions after ingestion of poppy seed-containing food by IgE-immunoblotting. Nine of 11 patients showed concomitant IgE binding to allergens of birch, mugwort or grass pollen in RAST-CAP, and suffered from characteristic seasonal symptoms. RESULTS: Ten of 11 patients showed IgE binding to a 45-kDa protein, 4/11 to a 34-kDa, 5/11 to a 17-kDa, 5/11 to a 14-kDa, and 3/11 to a 5-kDa component. Furthermore, individual IgE binding to proteins of 20, 25, 30 and 40 kDa proteins could be observed. Periodate treatment of blots markedly reduced the IgE binding capacity of the 40- and 45-kDa compounds, indicating the existence of IgE epitopes of the carbohydrate type. Inhibition studies indicated the presence of homologues of pollen allergens in extracts from poppy seeds, i.e. Bet v 1 and Bet v 2. CONCLUSION: The serological analysis showed IgE binding to protein and sugar components of poppy seeds. The 40- and 45-kDa allergens are glycoproteins and contain IgE binding carbohydrate moieties. Moreover, cross-reacting homologues of pollen allergens including Bet v 1 and profilin were detected in poppy seed extract.

Adolescent↗
PubMed1999

Component-resolved diagnosis (CRD) of type I allergy with recombinant grass and tree pollen allergens by skin testing.

The diagnosis of Type I allergy is based on the measurement of allergen-specific IgE antibodies and on provocation with allergens, most frequently conducted by skin testing. Both forms of diagnosis are currently performed with allergen extracts that are difficult to standardize regarding their allergen contents, and which contain additional undefined nonallergenic components. We report the expression in Escherichia coli and purification of some of the most relevant timothy grass- and birch pollen allergens. Recombinant timothy grass- (rPhl p 1, rPhl p 2, rPhl p 5) and birch pollen (rBet v 1, rBet v 2) allergens were purified and used for the measurement of allergen-specific IgE and IgG subclass responses as well as for skin prick testing in 55 pollen allergic patients and 10 nonatopic individuals. Results obtained showed that the recombinant allergens allowed in vivo allergy diagnosis in 52 of 54 of the grass pollen and in 35 of 36 of the birch pollen allergic patients. Positive skin reactions were observed almost exclusively in patients containing detectable allergen-specific IgE antibodies but not in the nonatopic group; however, sensitivity to a given allergen as measured by skin reactivity was weakly correlated with the levels of allergen-specific IgE. Our results demonstrate that recombinant allergens can be used for component-resolved skin test diagnosis (CRD) of the patients' allergen sensitization profile, whereas allergen extracts at best allow to identify allergen-containing sources. CRD may thus represent the basis for novel forms of patient-tailored immunotherapy.

Adult↗
PubMed1999

Tissue deposits of hydroxyethyl starch (HES): dose-dependent and time-related.

Tissue deposits occur after administration of plasma substitutes. After hydroxyethyl starch (HES), deposits may last for months, causing pruritus and impairment of function. Because elimination of HES deposits has not been demonstrated in humans, we studied 26 patients, for up to 7 yr after HES administration, to assess HES storage. HES dose ranged from 0.34 to 15.00 g kg-1 body weight, and administration intervals from 1 day to 7 yr. Biopsies of the liver, muscle, spleen, intestine or skin were studied using light and electron microscopy and immunohistochemistry. HES storage was dose-dependent, decreased in all organs with time and was greater in patients suffering from pruritus. We conclude that tissue deposition of HES is transitory and dose-dependent, with differences between subjects in severity and duration.

Adult↗
PubMed1999

Suppressive versus stimulatory effects of allergen/cholera toxoid (CTB) conjugates depending on the nature of the allergen in a murine model of type I allergy.

Recent reports have demonstrated that feeding small amounts of antigen conjugated to the B subunit of cholera toxin (CTB) suppress immune responses in experimental models of certain T(h)1-based autoimmune diseases. We have established a model of aerosol sensitization leading to T(h)2-mediated allergic immune responses in BALB/c mice. In the present study two different antigens, the dietary antigen ovalbumin (OVA) and the inhalant allergen Bet v 1 (the major birch pollen allergen), chemically coupled to recombinant CTB were tested for their potential to influence T(h)2-like immune responses. Intranasal administration of OVA-CTB prior to sensitization with OVA led to a significant decrease of antigen-specific IgE antibody levels, but a marked increase of OVA-specific IgG2a antibodies as compared to non-pretreated, sensitized animals. Antigen-specific lympho-proliferative responses in vitro were reduced by 65% in the pretreated group; IL-5 and IL-4 production were decreased in responder cells of lungs and spleens of nasally pretreated mice. In contrast, mucosal administration of rBet v 1-CTB conjugates prior to sensitization led to an up-regulation of allergen-specific IgE, IgG1 and IgG2a, increased in vitro lympho-proliferative responses as well as augmented production of IL-5, IL-4, IL-10 and IFN-gamma. Intranasal administration prior to sensitization of unconjugated allergens showed also contrasting effects: OVA could not significantly influence antigen-specific antibody or cytokine production, whereas intranasal pretreatment with unconjugated Bet v 1 suppressed allergen-specific immune responses in vivo and in vitro. These results demonstrated that the two antigens-in conjugated as in unconjugated form-had different effects on the T(h)2 immune responses. We therefore conclude that the tolerogenic or immunogenic properties of CTB-and probably also other antigen-delivery systems-strongly depend on the nature of the coupled antigen-allergen.

Administration, Intranasal↗