Previously, we have constructed recombinant derivatives of the major birch pollen allergen, Bet v 1, with a more than 100-fold reduced ability to induce IgE-mediated allergic reactions. These ...derivatives differed from each other because the two recombinant Bet v 1 fragments represented unfolded molecules whereas the recombinant trimer resembled most of the structural fold of the Bet v 1 allergen. In this study, we analyzed the Ab (IgE, IgG subclass, IgA, IgM) response to Bet v 1, recombinant and synthetic Bet v 1-derived peptides in birch pollen allergic patients who had been vaccinated with the derivatives or adjuvant alone. Furthermore, we studied the induction of IgE-mediated skin responses in these patients using Bet v 1 and Bet v 1 fragments. Both types of vaccines induced a comparable IgG1 and IgG4 response against new sequential epitopes which overlap with the conformational IgE epitopes of Bet v 1. This response was 4- to 5-fold higher than that induced by immunotherapy with birch pollen extract. Trimer more than fragments induced also IgE responses against new epitopes and a transient increase in skin sensitivity to the fragments at the beginning of therapy. However, skin reactions to Bet v 1 tended to decrease one year after treatment in both actively treated groups. We demonstrate that vaccination with folded and unfolded recombinant allergen derivatives induces IgG Abs against new epitopes. These data may be important for the development of therapeutic as well as prophylactic vaccines based on recombinant allergens.
Intravenous immunoglobulins have been used to treat autoimmune disorders (ADs) for over 50 years. The etiologies of various ADs are not fully understood and although intravenous immunoglobulin ...treatment has proved its immunomodulatory properties, the roles of proposed mechanisms of action also remain a matter of speculation. A systemic search of the literature regarding KIOVIG(®) (Baxalta US, Inc., MA, USA) use in clinical trials on patients with ADs and a detailed review of retrieved articles revealed eight relevant publications. These articles reported KIOVIG use in multifocal motor neuropathy, chronic inflammatory demyelinating polyneuropathy, idiopathic thrombocytopenic purpura, Kawasaki disease, Guillain-Barré syndrome and other autoimmune and neurologic disorders and showed that KIOVIG is an effective, safe and well-tolerated treatment in the studied populations. Nevertheless, further studies on larger patient cohorts are needed.
We have performed a double-blind, placebo-controlled injection immunotherapy study with genetically modified derivatives of the major birch pollen allergen, Bet v 1 (Bet v 1–trimer, Bet v ...1–fragments).
To investigate whether vaccination with genetically modified allergens induces allergen-specific antibodies in nasal secretions and to study whether these antibodies affect nasal allergen sensitivity.
A randomly picked subgroup of patients (n
=
23; placebo, n
=
10; trimer, n
=
10; fragments, n
=
3) was subjected to an extensive analysis of serum samples and nasal lavage fluids and to nasal provocation testing. Bet v 1–specific IgG
1-4 and IgA antibodies were determined in serum samples obtained before and after vaccination, after the birch pollen season, and 1 year after start of vaccination as well as in nasal lavage fluids obtained after the birch pollen season and 1 year after start of vaccination by ELISA. Nasal sensitivity to natural, birch pollen–derived Bet v 1 was determined by active anterior rhinomanometry after the birch pollen season and 1 year after start of vaccination.
Vaccination with genetically modified Bet v 1 derivatives, but not with placebo, induced Bet v 1–specific IgG
1, IgG
2, and IgG
4, and low IgA antibodies in serum, which also appeared in nasal secretions, but no IgG
3 antibodies. The levels of therapy-induced Bet v 1–specific IgG
4 antibodies in nasal secretions were significantly (
P < .05) associated with reduced nasal sensitivity to natural, birch pollen–derived Bet v 1 as objectively determined by controlled nasal provocation experiments.
Our data demonstrate that vaccination with genetically modified allergens induces IgG antibody responses against the corresponding natural allergen not only in serum but also in mucosal fluids, where they may protect against allergen-induced inflammation.
Hom s 2, the α-chain of the nascent polypeptide-associated complex, is an intracellular autoantigen that has been identified with IgE autoantibodies from atopic dermatitis patients. We investigated ...the humoral and cellular immune response to purified recombinant Hom s 2 (rHom s 2). rHom s 2 exhibited IgE reactivity comparable to exogenous allergens, but did not induce relevant basophil cell degranulation. The latter may be attributed to the fact that patients recognized single epitopes on Hom s 2 as revealed by IgE epitope mapping with rHom s 2 fragments. In contrast to exogenous allergens, rHom s 2 had the intrinsic ability to induce the release of IFN-γ in cultured peripheral blood mononuclear cells from atopic as well as non-atopic individuals. IFN-γ-containing culture supernatants from Hom s 2-stimulated peripheral blood mononuclear cells caused disintegration of respiratory epithelial cell layers and apoptosis of skin keratinocytes, which could be inhibited with a neutralizing anti-IFN-γ antibody. Our data demonstrate that the Hom s 2 autoantigen can cause IFN-γ-mediated cell damage.
Recently, recombinant hypoallergenic derivatives of the major birch pollen allergen, Bet v 1, were used to treat birch-pollen-allergic patients in a double-blind, placebo-controlled, multi-centre ...immunotherapy study. The aim of this study was to evaluate the effects of vaccination with aluminium-hydroxide-adsorbed recombinant Bet v 1 derivatives versus placebo on T-cell, cytokine and antibody responses in a subgroup of patients.
Blood was drawn from patients of the Swedish centre (n = 27; rBet v 1 fragments: n = 10; rBet v 1 trimer: n = 8, and placebo-aluminium hydroxide: n = 9) before the start and after completion of the treatment. PBMC were stimulated with rBet v 1 and analysed for cytokine (IL-4, IL-5, IL-10, IL-12, IL-13 and IFN-gamma)-secreting cells by ELISpot. Bet v 1-specific antibody levels in serum (IgG(1-4), IgE and IgA) were measured by ELISA. Skin prick tests with defined Bet v 1 concentrations were performed before and 10-11 months after the beginning of the study.
Bet v 1-specific IgG levels, consisting of IgG(1), IgG(2) and IgG(4), were significantly increased after treatment with recombinant allergen derivatives. Treatment with rBet v 1 trimer led to a significant (p < 0.05) reduction of Bet v 1-reactive IL-5- and IL-13-producing cells, reflecting a reduced Th2 response. In addition, a decreased number of Bet v 1-reactive IL-4 producing (p = 0.07) and an increase of IL-12-producing (p = 0.06) cells was noted in the trimer-treated patients. In contrast to placebo, active treatment resulted in significantly reduced immediate-type skin reactions to Bet v 1 even 10-11 months after treatment.
Vaccination with recombinant hypoallergenic Bet v 1 derivatives induces a Bet v 1-specific IgG response and leads to reduced skin reactivity in allergic patients. A reduction of Bet v 1-specific Th2 responses was observed in trimer-treated patients, which may reflect the intrinsic property of this allergen derivative.
Allergen-IgE immune complexes, in which the IgE paratopes are occupied by allergen, remain undetected in standard IgE-detection assays which are based on capturing specific IgE by allergens. We ...describe an assay for the detection of immune complexes consisting of IgE bound to one of the most frequent environmental allergens, the major birch pollen allergen, Bet v 1. This assay is based on a Bet v 1-specific monoclonal antibody, Bip 1, which binds to an epitope on Bet v 1 that is distinct from the epitopes recognized by allergic patients' IgE. IgE-immune complexes formed with sera from birch pollen-allergic patients (
n
=
46) were undetectable with solid phase-bound allergen but could be captured by Bip 1 immobilized to nitrocellulose membranes or ELISA plates and traced with radioactively or enzymatically labelled anti-human IgE antibodies. The levels of IgE complexed with Bet v 1 measured in our assays were highly correlated with the amounts of non-complexed allergen-specific IgE as determined by the ImmunoCAP assay which is based on solid phase-bound IgE (
r
=
0.95;
p
<
0.01). Bet v 1-specific IgE could even be detected at serum dilutions below the cut off of the ImmunoCAP system (i.e., 0.35 kUA/L). We have thus developed a robust and sensitive assay for the detection and quantification of Bet v 1-IgE immune complexes which should be useful to measure allergen-bound IgE in human body fluids and in
in vitro experiments.
Respiratory allergen contact is the critical event in the elicitation and boosting of allergen-specific immune responses, as well as in the induction of immediate and late inflammatory reactions.
We ...sought to investigate the influence of various factors of allergic inflammation on the integrity and barrier function of respiratory epithelium for allergens.
We cultured the human bronchial epithelial cell line 16HBE14o− in a transwell culture system as a surrogate of intact respiratory epithelium and used purified iodine 125–labeled recombinant major birch pollen allergen (rBet v 1) to study the extent, kinetics, and factors influencing transepithelial allergen penetration.
Culture supernatants from activated allergen-specific T
H1 clones decreased transepithelial resistance. A screening of various factors (histamine, IFN-γ, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-8, IL-12, and TNF-α) identified IFN-γ as a potent factor capable of reducing epithelial barrier properties and enhancing transepithelial allergen penetration. Increased submucosal allergen concentrations caused by IFN-γ–mediated reduction of epithelial barrier function provoked a more than 7-fold augmentation of histamine release from sensitized basophils.
These results demonstrate that the T
H1 cell–derived cytokine IFN-γ facilitates allergen penetration through the respiratory epithelium and thereby can aggravate allergic inflammation.
Hom s 2, the alpha-chain of the nascent polypeptide-associated complex, is an intracellular autoantigen that has been identified with IgE autoantibodies from atopic dermatitis patients. We ...investigated the humoral and cellular immune response to purified recombinant Hom s 2 (rHom s 2). rHom s 2 exhibited IgE reactivity comparable to exogenous allergens, but did not induce relevant basophil cell degranulation. The latter may be attributed to the fact that patients recognized single epitopes on Hom s 2 as revealed by IgE epitope mapping with rHom s 2 fragments. In contrast to exogenous allergens, rHom s 2 had the intrinsic ability to induce the release of IFN-gamma in cultured peripheral blood mononuclear cells from atopic as well as non-atopic individuals. IFN-gamma-containing culture supernatants from Hom s 2-stimulated peripheral blood mononuclear cells caused disintegration of respiratory epithelial cell layers and apoptosis of skin keratinocytes, which could be inhibited with a neutralizing anti-IFN-gamma antibody. Our data demonstrate that the Hom s 2 autoantigen can cause IFN-gamma-mediated cell damage.
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