IgG and IgE antibody patterns after immunotherapy with monomethoxy polyethyleneglycol modified honey bee venom

An alternative method for purifying and detoxifying diphtheria toxin

Infections caused by Corynebacterium diphtheriae frequently induce situations in which very small doses of antigens injected intradermally can cause strong inflammatory reactions. This bacterium secretes the diphtheria toxin (DT), a virulence factor that can be lethal to the human organism at doses below 0.1 μg/kg of body weight. The present work proposes alternative methods of DT purification using affinity chromatography and of DT detoxification through conjugating with the polymer methoxypolyethylene glycol activated (mPEG). Tests were performed to evaluate: the formation of edemas and the presence of dermonecrotic activity, in vitro cytotoxicity to Vero cells, the neutralizing activity of serum from guinea pigs immunized with the diphtheria toxoid inactivated with mPEG, and the immunogenic activity of the purified and modified toxin. The results indicated that purification with Blue Sepharose was an efficient method, yielding antigen purity equivalent to 2600 Lf/mg of protein nitrogen. The modification of the Purified Toxin with mPEG did not result in the formation of edema or necrosis although it was immunogenic and stimulated the formation of antibodies that could neutralize the Purified Toxin. The toxoid obtained from the purified toxin maintained its immunogenic characteristics, inducing antibodies with neutralizing activity; edema and necrosis were still observed, however.

Hymenoptera venom allergens

Hymenoptera venoms each contain a variety of protein allergens. The major components have all been characterized, and most of the amino acid sequences are known. This article concentrates on the use of contemporary techniques including cloning, mass spectrometry and genomics in the characterization of venom allergens, and newer separation techniques for protein isolation. Examples of the use of these techniques with venom proteins are presented.

Epitope-specific suppression of antibody response in experimental autoimmune myasthenia gravis by a monomethoxypolyethylene glycol conjugate of a myasthenogenic synthetic peptide

A synthetic peptide corresponding to a myasthenogenic region of Torpedo californica acetylcholine (AcCho) receptor (AcChoR) alpha subunit, AcChoR alpha-(125-148), was conjugated to monomethoxypolyethylene glycol (mPEG). Injection of mice with the mPEG-AcChoR alpha-(125-148) conjugate and subsequent immunization with whole Torpedo AcChoR suppressed the development of experimental autoimmune myasthenia gravis (EAMG) by electrophysiological criteria. In anti-AcChoR sera from these animals, the antibody response against unconjugated AcChoR alpha-(125-148) was decreased, while the antibody responses against whole AcChoR and other epitopes were not altered. There were no detectable changes in T-cell proliferation responses to AcChoR alpha-(125-148) or to whole AcChoR in these animals. Prior injections with a "nonsense" peptide-mPEG conjugate had no effect on responses to the subsequent immunization with whole Torpedo AcChoR. The results indicate that the mPEG-AcChoR alpha-(125-148) conjugate has epitope-specific tolerogenicity for antibody responses in EAMG and that the AcChoR alpha-subunit region comprising residues 125-148 plays an important pathophysiological role in EAMG. The epitope-directed tolerogenic conjugates may be useful for future immunotherapies of human myasthenia gravis. The strategy of specific suppression of the antibody response to a predetermined epitope by using a synthetic mPEG-peptide conjugate may prove useful in manipulation and suppression of unwanted immune responses such as autoimmunity and allergy.

Synthesis of tolerogenic monomethoxypolyethylene glycol and polyvinyl alcohol conjugates of peptides

Recent studies from this laboratory showed that tolerogenic peptide conjugates are very effective reagents for obtaining epitope-specific immunosuppression of antibody responses to immunopathogenic sites on multideterminant complex protein antigens. This paper describes the procedure for synthesis of well-defined conjugates of peptides to monomethoxypolyethylene glycol (mPEG) or to polyvinyl alcohol (PVA). The first step involves succinylation of the hydroxyl groups on the polymers by reaction with succinic anhydride. The polymer is then coupled via the carboxyl of the succinyl group to the alpha-NH2 of the completed peptide on the synthetic resin, while maintaining intact all the side-chain protecting groups on the peptide. The mPEG or PVA-peptide conjugates are cleaved from the resin and purified by standard procedures. This method results in the preparation of conjugates in which one molecule of tolerogenic polymer is coupled to the N-terminal of an otherwise unaltered peptide molecule.

IgE and IgG antibodies of patients with allergy to birch pollen as tools to define the allergen profile of Betula verrucosa

IgE and IgG antibody response to birch pollen antigens were studied by means of immunoblotting experiments testing 58 sera from patients with Type I allergy to birch pollen. 56/58 patients showed IgE antibodies reactive with Bet v I, a 17 kilodalton (kD) pollen protein. 2D-electrophoresis/immunoblot revealed a heterogeneity of that protein. Ten spots (pH 4.9-5.9) could be detected, presumably representing differentially glycosylated isoallergens. In 33/58 patients, there was no evidence of IgE antibodies directed against allergens other than Bet v I. However, in 25/58 of patients' sera, 11 minor allergens (13, 15, 18, 27, 29, 32, 39, 44, 57, and 68 kD) with individual incidences from 1.7% to 17.2% were identified. All proteins were also recognized by the patients' IgG antibodies: in the case of Bet v I recognition was weak, whereas the IgG response to the minor allergens was pronounced. Sera from healthy individuals showed similar IgG antibody responses, but no IgG to the 15, 27, and 29 kD proteins. Our results suggest that IgG directed against minor allergens may function as trapping antibodies in healthy individuals. Too low or lacking amounts of anti-Bet v I IgG may facilitate an allergic reaction.

Hymenoptera venom immunotherapy. I. Induction of T cell-mediated immunity by honeybee venom immunotherapy: relationships with specific antibody responses

The specific cell-mediated and humoral immune responses of 14 children allergic to honeybee venom were studied. An 8-day rush venom immunotherapy induced an increase in T proliferative (p less than 0.04) and T suppressive (p less than 0.003) cell-specific activities. Antibody variations, an increase in specific IgG4 (p not equal to 0.05), and a decrease in specific IgE (p less than 0.01) were observed 1 year later. Initial high T suppressive cell activity prevents T proliferative cell increase during rush venom immunotherapy. High initial levels of specific IgG1 and specific IgG4 have opposing effects on the increase in T suppressive cell activity, the former being positively correlated with intensive increase (r = 0.840; p less than 0.005), the latter negatively with T suppressive cell increase (r = -0.709; p less than 0.001). These data indicate that there are interrelationships between the cell-mediated immunity and the antibody responses in honeybee allergy.

Immunotherapy with Hymenoptera venoms. Position paper of the Working Group on Immunotherapy of the European Academy of Allergy and Clinical Immunology

Immunotherapy with Hymenoptera venoms is widely used throughout the world and is accepted as an effective treatment for most patients with Hymenoptera venom allergy. There are, however, still some unresolved problems with this form of treatment. At present there is no definite test which makes it possible to identify patients at risk - and thus candidates for immunotherapy - unequivocally. On the basis of prospective studies on the natural history of Hymenoptera allergy, venom immunotherapy is indicated in adults with severe systemic anaphylaxis. It is usually not necessary in patients with large local reactions only. Children with mild systemic reactions, e.g. urticaria, will need immunotherapy only in case of repeated reactions and/or a high risk of re-exposure. The selection of venoms for immunotherapy may lead to some confusion owing to common antigenic determinants shared by venoms of various Hymenoptera species. Many different regimens for immunotherapy have been proposed. At present, the three main are: rush, stepwise or clustered and classical. The maintenance dose of 100 micrograms usually protects from life-threatening reactions. However, in some patients 200 micrograms are necessary for complete protection. The usual interval between maintenance injections is 4 to 6 weeks. In many patients a strong increase of venom specific serum IgG-antibodies usually parallels clinical protection induced by venom immunotherapy, although many exceptions have been reported. Allergic side effects of venom immunotherapy are not rare, especially with honey bee venom and during the initial phase of dose increase. The question of the duration of venom immunotherapy is handled differently: although some authors recommend treatment for life, most suggest treating patients until skin tests and RAST become negative.

A preliminary study of immunotherapy with a monomethoxy polyethylene glycol modified honey bee venom preparation

Monomethoxy polyethylene glycol (mPEG) modified honey bee venom (HBV) immunotherapy (IT) has been studied in 14 patients allergic to honey bee venom. Doses could be increased more rapidly and higher doses were reached compared to regular venom immunotherapy. No general side effects were seen, although large local swellings were found somewhat more often than with regular HBV. Most patients could easily be switched from the modified to the unmodified venom. Eight patients experienced and tolerated field stings. Skin testing showed a decreased allergenicity of the mPEG-HBV. The mean HBV-specific IgE level was below pre-treatment level already after only 6 weeks of IT. The HBV-specific IgG response was very good.