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PubMed1990

[Hyposensitization in pollinosis. Results of a 3-year controlled study with 2 depot-allergoid grass pollen extracts: aluminum hydroxide-adsorbed allergoid and tyrosine-adsorbed allergoid].

For controlled hyposensitization treatment over a period of three years 36 patients with confirmed grass pollen sensitization had been selected in 1986 and randomly distributed to receive preseasonal injection therapy: 23 patients were treated with an average of seven AGD (aluminium-adsorbed allergoid) injections, and 13 patients had received six TA (tyrosine-adsorbed allergoid) injections. Evaluation of the trial data collected during three years of preseasonal treatment showed the following results of tolerance and efficacy: Systemic side-reactions registered during therapy were only mild and transient and occurred in the average after 3% of the AGD injections and after 10% of the TA injections. Local reactions over 5 cm diameter were registered after 7% in the AGD group and after 9% in the TA group. Before therapy there was no significant difference (p greater than 0.05) between the groups; after three years of therapy the AGD injections had resulted in a mean net rise of specific IgG of 220% (significant, p = 0.001); during the same time, TA injections had resulted in a final net increase of 10% (not significant, p greater than 0.05). Both treatment forms did not lead to any statistically relevant changes of specific IgE values. After three years of hyposensitization treatment, patients of both groups had improved; but an advantage was documented for patients treated with AGD on the basis of scores for objective assessment as well as for registered symptom and medication scores.

Adult↗
PubMed1987

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. I. Rush immunotherapy with allergoids and standardized orchard grass-pollen extract.

Forty-five grass pollen-allergic patients were randomly assigned to three groups according to their skin test and RAST sensitivities and the severity of seasonal rhinitis. Eleven patients were treated with placebo (group 1), 19 patients (group 2) were treated with a six-mixed grass-pollen allergoid prepared by mild formalinization with a two-step procedure, and 15 other patients were treated with a standardized orchard grass-pollen extract (group 3). Because of a different immunotherapy schedule, only patients placed in groups 1 and 2 received the extracts in a double-blind fashion. Rush immunotherapy was performed in 3 to 6 days, and the maintenance dose was subsequently administered weekly for 4 weeks and every 2 weeks until the end of the grass-pollen season. During the season, a coseasonal treatment was administered. Systemic reactions occurred during the rush protocol in 36.8% of patients treated with allergoid and 20% of patients who received the standardized extract. Only patients treated with allergoid had systemic reactions during maintenance dose. The reactions observed with the standardized extract were more severe. Total doses of allergoid ranged from 2350 to 13,500 protein nitrogen units. Symptoms and medication scores during the peak of the season were analyzed. Patients treated with the standardized allergen had a significant reduction of the number of days of symptoms during the month of June (9.5 +/- 6.7 days; p less than 0.005) and of medication scores (1.3 +/- 1.4; p less than 0.01) compared to patients receiving placebo (19.4 +/- 8.1 days; medication score, 2.8 +/- 2.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1990

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. IV. Comparison of the safety and efficacy of two dosages of a high-molecular-weight allergoid.

Specific immunotherapy is still widely used in grass-pollen allergy, but its side effects may limit its use. We tested the safety and efficacy of a formalinized high-molecular-weight allergoid prepared from a mixed grass-pollen extract with two injection schedules in a double-blind, placebo-controlled study. Eighteen patients received placebo, 19 received the low-dose schedule (maximal dose: 2000 PNU) and 20 received the high-dose schedule (maximal dose: 10,000 PNU). Only one patient presented a systemic reaction of moderate severity for a dose of 1200 PNU. Before the onset of the pollen season, patients had a nasal challenge with orchard grass-pollen grains, a skin test titration, and the titration of serum-specific IgG. Both groups of patients presented a significant reduction in nasal and skin sensitivities and a significant increase in IgG compared to placebo. Symptoms and medications for rhinitis and asthma were studied during the season, and both groups receiving allergoids had a significant reduction of symptom-medication scores for nasal and bronchial symptoms. There was a highly significant correlation between nasal symptom-medication scores during the season and the results of nasal challenges. High-molecular-weight allergoids are safe and effective.

Adolescent↗
PubMed1981

Studies on allergoids from naturally occurring allergens. III. Preparation of ragweed pollen allergoids by aldehyde modification in two steps.

We have devised a new process for modifying heat-labile allergens, which employs a sequential "two-step" incubation at temperatures of 10 degree C and 30 degree to 32 degree C. This process was found to produce effective ragweed "allergoids" with low allergenicity and good immunogenicity, which makes them useful for the therapy of allergic humans. Modification with formaldehyde produced derivatives ("formallergoids") that were about 10-fold less allergenic in allergic humans (as measured by leukocyte histamine-release assay), and similarly or more immunogenic in guinea pigs, than glutaraldehyde-modified allergens ("glutarallergoids"). Further analysis by RAST inhibition showed that a ragweed formallergoid was sixfold less reactive than a glutarallergoid with a pool of human IgE antibodies. However, the formallergoid had retained the ability to induce a wide array of antibodies against native ragweed antigens, since rabbit anti-formallergoid serum was able to recognize at least 12 different ragweed antigens, including AgE. Gel-filtration experiments showed that both the formallergoid and glutarallergoid materials contained polymers having apparent molecular weights distributed around 260,000 and 230,000 daltons, respectively (approximate range 30,000 to 900,000 daltons). Our studies provide the immunochemical basis for the use of these allergoids in the therapy of allergic humans.

Aldehydes↗
PubMed1999

Reactivity of T cells with grass pollen allergen extract and allergoid.

BACKGROUND: Successful allergen-specific immunotherapy is achieved with progressively increasing doses of allergen or allergoid. In order to gain further insight into the mechanism of action of allergoids several in vitro investigations were conducted. METHODS: Peripheral blood mononuclear cells (PBMC) from grass pollen allergic and nonallergic subjects were stimulated with either grass pollen extract or allergoid and the proliferation and cytokine production (IL-5, IFN-gamma) were measured. Similar investigations were performed with Phl p 5-specific T cell lines (TCL) and clones (TCC). Dendritic cells and PBMC were compared in terms of their relative efficacies as antigen-presenting cells. RESULTS: Both allergen and allergoid induced proliferation and Th2 and Th1 cytokine synthesis by PBMC of allergic subjects, whereas PBMC of nonallergic subjects did not produce IL-5. The maximum level of IL-5 was obtained with a lower concentration than was necessary for maximal IFN-gamma production. Higher stimulation doses of allergen and allergoid shifted the cytokine profiles towards a Th1 phenotype. TCL and TCC clearly showed reactivity with both allergen and allergoid when using autologous PBMC for antigen presentation, but compared with the native allergen the reactivity of the allergoid was reduced with most of the TCC. Using dendritic cells for antigen presentation a pronounced increase of stimulation of the TCC especially for the allergoids becomes obvious. CONCLUSION: In common with grass pollen allergen the corresponding allergoids possess a strong allergen-specific T cell-stimulating capacity. However, the degree of T cell stimulation by the allergoid seems to be dependent on the type of the antigen-presenting cell. Both, allergen and allergoid, can modulate T cell responses in a dose-dependent manner.

Allergens↗
PubMed1996

Characterization of allergoids from ovalbumin in vitro and in vivo.

Several in vivo and in vitro methods for monitoring immunological properties of two allergoids obtained by formaldehyde treatment of ovalbumin (OA) were developed. The calculated molecular weight of allergoids was 80 kD (OA-F1) and 165 kD (OA-F2), respectively. The allergenic activity in vitro of allergoids in mast-cell histamine release assay was 1000 times lower than of OA. Both allergoids showed reduced ability to induce passive cutaneous anaphylaxis in the Sprague-Dawley rats or systemic anaphylaxis in Dunkin-Harley guinea-pigs. The ability of OA and allergoids to bind to the OA-specific IgE antibodies was measured in vivo by the inhibition of passive cutaneous anaphylaxis (PCA-inhibition). Allergoid binding to IgE was 51-66% lower than the native allergen. Moreover, the avidity of OA-specific IgG antibodies, measured by ELISA-inhibition, for allergoids and allergen was of the same order. Allergoids induced a different pattern of humoral immune response from that, induced by the native allergen. Thus, after immunization of BALB/c mouse, both allergoids induced a higher production of IgG and a lower production of IgE than OA, only OA-F2 induced a lower production of IgG1. The differences in the IgA response to the immunogens was not significant. Delayed hypersensitivity studies in the BALB/c mouse showed that allergoids were 5- to 12-times less effective in inducing a cell-mediated immune response than OA. The present study provides a battery of immunological methods for preclinical testing of modified allergens.

Allergens↗
PubMed1982

Controlled evaluation of allergoid in the immunotherapy of ragweed hay fever.

Immunotherapy with ragweed allergoid administered in a clustered regimen, placebos in a clustered regimen, and unaltered ragweed extract (allergen) in a weekly regimen were compared in three groups of hay fever patients carefully matched for ragweed sensitivity. The allergoid and placebo comparison was performed double-blind and the unaltered ragweed extract comparison was single-blind. In terms of antigen E (AgE) equivalents, doses were about 50 times higher in the allergoid-treated group than in the allergen-treated group. Whereas there was no immunologic response to placebos, the allergoid regimen produced a more rapid serum IgG antibody response, with significantly higher posttreatment levels than those in the allergen regimen. Initial IgE antibody rises and subsequent slow declines were similar. Symptom-medication scores were similar in the two specifically treated groups and significantly less than scores reported by the placebo group (p less than 0.01). Due to an overestimate of the initial allergoid doses, systemic reactions occurred mostly in the early visits with allergoid treatment, whereas systemic reactions appeared late in the allergen treatment. The overall incidence was similar. In a second year, after 8 mo of no injections, a preseasonal booster regimen with both materials produced virtually no untoward reactions. During the period of no injections, IgG antibody declines were modest and, after boosters, IgG antibody levels rose promptly. Clinical results in both groups were again excellent, with an advantage for allergoid.

Allergens↗
PubMed2000

T cell reactivity with allergoids: influence of the type of APC.

The use of allergoids for allergen-specific immunotherapy has been established for many years. The characteristic features of these chemically modified allergens are their strongly reduced IgE binding activity compared with the native form and the retained immunogenicity. T cell reactivity of chemically modified allergens is documented in animals, but in humans indirect evidence of reactivity has been concluded from the induction of allergen-specific IgG during immunotherapy. Direct evidence of T cell reactivity was obtained recently using isolated human T cells. To obtain further insight into the mechanism of action of allergoids, we compared the Ag-presenting capacity of different APC types, including DC and macrophages, generated from CD14+ precursor cells from the blood of grass pollen allergic subjects, autologous PBMC, and B cells. These APC were used in experiments together with Phl p 5-specific T cell clones under stimulation with grass pollen allergen extract, rPhl p 5b, and the respective allergoids. Using DC and macrophages, allergoids exhibited a pronounced and reproducible T cell-stimulating capacity. Responses were superior to those with PBMC, and isolated B cells failed to present allergoids. Considerable IL-12 production was observed only when using the DC for Ag presentation of both allergens and allergoids. The amount of IL-10 in supernatants was dependent on the phenotype of the respective T cell clone. High IL-10 production was associated with suppressed IL-12 production from the DC in most cases. In conclusion, the reactivity of Th cells with allergoids is dependent on the type of the APC.

Allergens↗
PubMed2002

The influence of a residual group in low-molecular-weight allergoids of Artemisia vulgaris pollen on their allergenicity, IgE- and IgG-binding properties.

BACKGROUND: Reaction of epsilon-amino groups of lysine with potassium cyanate, maleic, or succinic anhydride leads to allergoids of low molecular weight. No study has been performed to compare their properties and investigate the influence of a residual group on allergenicity and human IgE- and IgG-binding of these derivatives. METHODS: Allergoids of a pollen extract of Artemisia vulgaris were obtained by means of potassium cyanate, and succinic and maleic anhydride. Biochemical properties were investigated by determination of amino groups, enzyme activity, isoelectric focusing IEF and SDS-PAGE. IgE- and IgG-binding was determined using immunoblots and ELISA inhibition. Allergenicity was investigated by skin prick tests (SPT) on a group of 52 patients, of which 6 were control subjects, 30 were patients with no previous immunotherapy (IT), and 16 were patients undergoing immunotherapy. RESULTS: The same degree of amino-group modification (more than 85%), residual enzyme activity (less then 15%), IEF, and SDS-PAGE pattern were noted. In the immunoblots of IgE-binding, there was more pronounced reduction in the succinyl and maleyl derivatives than in the carbamyl one. IgG-binding was less affected by carbamylation than by acid anhydride modification. The SPT showed that the succinylated derivative had the most reduced allergenicity (98% showed a reduced wheal diameter when tested with the succinyl derivative, 87% with the maleyl allergoid, and 83% with the carbamyl allergoid). The most significant difference among allergoids could be seen in the group of patients with high skin reactivity (83% of patients showed no reaction to the succinyl derivative when compared to the value of 28% for the carbamyl derivative or 22% for the maleyl derivative). CONCLUSIONS: According to our results, all three modification procedures yielded allergoids with a similar extent of modification. No single biochemical parameter investigated in the study could predict the degree of reduced allergenicity in vivo. The most reduced allergenicity was seen in the succinyl derivative while the preservation of IgG binding epitopes was of the highest degree for the carbamyl derivative.

Adolescent↗
PubMed1998

Responses of human birch pollen allergen-reactive T cells to chemically modified allergens (allergoids).

BACKGROUND: Allergoids are widely used in specific immunotherapy for the treatment of IgE-mediated allergic diseases. OBJECTIVE: The aim of this study was to analyse whether a modification of birch pollen allergens with formaldehyde affects the availability of T-cell epitopes. METHODS: Efficient modification of the allergens was verified by determining IgE and IgG binding activity using ELISA inhibition tests. T-cell responses to birch pollen allergoids were analysed in polyclonal systems, using peripheral blood mononuclear cells (PBMC) of five birch pollen-allergic individuals, as well as birch pollen extract-reactive T-cell lines (TCL), established from the peripheral blood of 14 birch pollen-allergic donors. To determine whether the modification of natural (n)Bet v 1 with formaldehyde or maleic anhydride results in epitope-specific changes in T-cell reactivities, 22 Bet v 1-specific T-cell clones (TCC), established from nine additional birch pollen-allergic individuals, were tested for their reactivity with these products. RESULTS: The majority of PBMC and TCL showed a reduced response to the birch pollen extract allergoid. Bet v 1-specific TCC could be divided into allergoid-reactive and -non-reactive TCC. No simple correlation between possible modification sites of formaldehyde in the respective T-cell epitopes and the stimulatory potential of the allergoid was observed. Mechanisms of suppression or of anergy induction were excluded as an explanation for the non-reactivity of representative TCC. All TCC could be stimulated by maleylated and unmodified nBet v 1 to a similar extent. CONCLUSION: These results demonstrate differences in the availability of T-cell epitopes between allergoids and unmodified allergens, which are most likely due to structural changes within the allergen molecule.

Allergens↗
PubMed1999

Immunohistochemical investigation of the cellular infiltrates at the sites of allergoid-induced late-phase cutaneous reactions associated with pollen allergen-specific immunotherapy.

BACKGROUND: Reduction in the size of the allergen-induced late-phase reaction (LPR) is seen as a consequence of successful allergen specific immunotherapy. OBJECTIVE: It was the aim of this study to characterize the cellular infiltrate at the sites of cutaneous LPR that may occur following injection of a depot pollen allergoid (Allergovit(R)) during immunotherapy and thereby determine the immunological nature of the response. METHODS: Punch biopsies were taken 24 h after subcutaneous injection of a depot pollen allergoid from eight patients that showed LPR and a further five patients that did not. Additional biopsies taken 24 h after injection of allergoid-free depot in the same patients served as controls. Immunoenzymatic labelling of the cryostat sections with different antibodies was performed with the APAAP technique. Results were expressed as cells/field (400 x magnification). RESULTS: Similar dermal cellular infiltrations were seen following depot allergoid injections in patients both with and without LPR. Patients with LPR showed statistically significant increases in total cells, CD4+ cells, CD11c+ cells, CD45RO+ cells, CD45RB+ cells and activated eosinophils at the reactions sites as compared with control sites. In patients without LPR CD11c+ cells, HLA-DR+ cells and CD45RA+ T cells increased significantly. CD8+, CD1a+, NP57+, CD23+ and CD25+ cells did not differ significantly in either group. CONCLUSION: These results indicate that activation of T cells, monocytes/macrophages and eosinophils at the sites of LPR following injection of depot allergoid are comparable with those following injection of allergen. Even in the absence of a cutaneous LPR, subsets of T cells and monocytes/macrophages increased. These cell activations may reflect events associated with the mechanisms of allergoid-based specific immunotherapy, and suggest that at least part of the late-phase reaction may be independent of IgE.

Adult↗
PubMed2001

Pharmacokinetics of an allergen and a monomeric allergoid for oromucosal immunotherapy in allergic volunteers.

BACKGROUND AND OBJECTIVE: Little is known about the pharmacokinetics of allergens for local immunotherapy. Thus, we studied the pharmacokinetics in allergic volunteers of a commercial allergenic vaccine in orosoluble tablets (LAIS(R), Lofarma S.p.A). METHODS: The carbamylated monomeric allergoid derived from Parietaria judaica major allergen (Par j 1), characterized by maintenance of the original molecular size, and the native allergen, were radiolabelled with 123I, then incorporated into the commercial soluble tablets and administered to allergic subjects. Early sequential and late static scintigraphic acquisitions were performed, and plasma radioactivity was measured at different time intervals. RESULTS: No difference in local pharmacokinetics was observed between the allergen and the allergoid: part of the tracer was retained in the mouth for at least 2 h after swallowing. No direct absorption through the oral mucosa could be detected, as plasma radioactivity increased only after swallowing and peaked at 2 h. However, the plasma peak attained with the allergoid in tablets was significantly higher with respect to the native allergen. Finally, some undegraded allergoid, but not the allergen, could be constantly detected in the bloodstream at plasma peak. CONCLUSIONS: The results showed a similar behaviour of the allergoid and the allergen in tablets as far as their local kinetics are concerned, whereas plasma peak was higher with the allergoid than with the allergen. Therefore we conclude that the chemical modification of the allergen may affect its pharmacokinetics, by making it less susceptible to enzymatic degradation.

Administration, Sublingual↗
PubMed2006

The effects of grass pollen allergoid immunotherapy on clinical and immunological parameters in children with allergic rhinitis.

Allergoid immunotherapy is a new form of allergen immunotherapy allowing safe administration of high allergen doses. There is limited information on the effects of allergoid immunotherapy in children with allergic rhinitis. To investigate the immunological and clinical effects of allergoid immunotherapy in children with allergic rhinitis due to grass pollen allergy. Children with allergic rhinitis were assigned to allergoid immunotherapy (n = 27) or control (n = 26, no immunotherapy) groups. Children in the immunotherapy group received seven injections of grass pollen allergoid immunotherapy before grass pollen season and continued to receive maintenance immunotherapy for 27 months. All patients were offered a pharmacotherapy regimen to be used on demand during the pollen seasons. Clinical and laboratory parameters were compared between the immunotherapy and control groups. The rhinoconjunctivitis symptom-medication score and asthma symptom score were lower in the immunotherapy group after 1 yr of maintenance immunotherapy (p < 0.01 for both). Skin test reactivity and nasal reactivity as determined by nasal provocation testing for grass pollen were significantly decreased after 1 yr of immunotherapy (p < 0.001 for both). The seasonal increase in bronchial reactivity and nasal lavage eosinophil cationic protein levels were prevented after the first year of immunotherapy (p < 0.05 for both). The seasonal increase in immunoglobulin (Ig)E decreased (p < 0.05) and grass-specific IgG, IgG(1) and IgG(4) increased significantly already at the end of the seven-injection build-up therapy (p < 0.001, for all). Interleukin (IL)-4 levels in the culture supernatants showed a steady decline from baseline at first and second year of immunotherapy (p < 0.001) but remained unchanged in the control group. Allergoid immunotherapy is an effective method in the treatment of grass pollen-induced allergic rhinitis in children and prevents the seasonal increase in bronchial hyper-reactivity. Changes in specific IgE and IgG levels and decreased IL-4 production in peripheral blood mononuclear cell culture supernatants may account for the observed clinical effects.

Adolescent↗
PubMed2005

Allergoid-specific T-cell reaction as a measure of the immunological response to specific immunotherapy (SIT) with a Th1-adjuvanted allergy vaccine.

BACKGROUND: Specific immunotherapy (SIT) is believed to modulate CD4+ T-helper cells. In order to improve safety, SIT vaccines are often formulated with allergoids (chemically modified allergens). Interaction between T-cells and allergoids is necessary to influence cellular cytokine expression. There have been few reports on identification the early cellular effects of SIT. METHOD: Patients allergic to grass and/or mugwort pollen (n= 21) were treated with a 4-shot allergy vaccine (Pollinex Quattro) containing appropriate allergoids (grass/rye and/or mugwort) adsorbed to L-tyrosine plus a Th1 adjuvant, monophosphoryl lipid A (MPL). Fourteen grass-allergic patients served as untreated controls. Using the peripheral blood mononuclear cells of these patients, an optimized lymphocyte transformation test (LTT) was employed to monitor the in vitro proliferative response of T-cells to an allergoid challenge (solubilised Pollinex Quattro) before the first and last injection and then 2 and 20 weeks after the final injection. Control challenges utilised preparations of a similar pollen vaccine without the adjuvant MPL and a tree pollen vaccine with and without MPL. RESULTS: The LTT showed increased LTT stimulation indices (SI) in 17/20 SIT patients when the solublised vaccine preparation was used as a challenge before the last injection and 2 weeks after, in comparison to pre-treatment levels. Twenty weeks after therapy, the SI decreased to baseline level. A vaccine challenge without MPL gave lower SI levels. A challenge of a clinically inappropriate tree allergoid vaccine gave no response, and a nontreated group also showed no response. CONCLUSION: Following a short-course SIT adjuvated with MPL, challenges of allergoids were shown to activate allergen-specific T cells in vitro. There was an additional stimulating effect when the challenge was in combination with MPL. There were no non-specific effects of MPL, shown by the tree allergoid/MPL control. The timing of the response was closely correlated to the treatment course; reactivity fell two weeks after the final injection and 20 weeks later it was at baseline level. Thus an immunological response to SIT was detected after very few injections. This methodology could provide a basis for monitoring the immediate progress of allergy vaccinations.

Adjuvants, Immunologic↗
PubMed1999

Physicochemical and immunologic characterization of low-molecular-weight allergoids of Dactylis glomerata pollen proteins.

BACKGROUND: Orchard grass (Dactylis glomerata) pollen proteins were chemically modified by means of acid anhydrides (maleic and succinic anhydride) to obtain low-molecular-weight allergoids. Chemical modification in both cases led to the replacement of one positive charge (epsilon amino group of Lys) by one negative charge, yielding proteins with changed physicochemical properties in comparison to the native orchard grass-pollen proteins. METHODS: Physicochemical characterization of derivatives was done by gel chromatography, SDS-PAGE, and isoelectric focusing. To examine the IgE-binding properties of these derivatives, we carried out immunoblotting. To examine the ability of derivatives to induce IgG production, we immunized rabbits. Skin prick testing with the allergoids was performed on 15 individuals allergic to orchard grass pollens and on two healthy subjects. RESULTS: It was shown that the modified proteins retain their original molecular weights, but change pI to more acidic values. In the case of allergoids, a strong reduction in IgE binding was found. Immunization of rabbits with allergoids showed that the derivatives retain the ability to induce IgG production, and that the antisera obtained in such a way react to native (unmodified) extract. The ability of derivatives to induce allergic reaction was significantly reduced. The patients (86.6%) included in our study exhibited less than 50% of native extract response. Among them, 53.3% had no response to one or both allergoids. CONCLUSIONS: These modification procedures yield allergoids with a reduced allergenic activity and preserved immunogenic potential suitable for use in immunotherapy.

Allergens↗
PubMed2002

Allergenic relevance of Cupressus arizonica pollen extract and biological characterization of the allergoid.

BACKGROUND: Cupressaceae (cypress) pollens can cause pollinosis in winter. However, the lack of specific commercial extracts combined with the early pollination period of cypress trees make a precise diagnosis difficult. The need for a reliable and effective cypress extract for diagnostic and therapeutic purposes is increasingly felt. METHODS: Mixed or single Cupressus arizonica, lusitanica and sempervirens pollen extracts precipitated with ammonium sulfate (PPT) were compared by direct RAST, RAST inhibition and SDS-PAGE techniques. The major allergen of C. arizonica (Cup a 1), purified by anion exchange chromatography, was checked by immunoblotting experiments before chemical modification, in parallel with a C. arizonica extract, with potassium cyanate (KCNO) to obtain a monomeric allergoid. The allergoid extract was characterized for its biological, chemico-physical and immunological features by RAST inhibition, SDS-PAGE and ELISA assays. RESULTS: Direct RAST, RAST inhibition, and SDS-PAGE data indicated that the PPT C. arizonica pollen extract showed the most allergenic potential, and it can be considered representative of the Cupressus spp. Immunoblotting data confirmed Cup a 1 as a major allergen. RAST inhibition and ELISA showed that modified PPT C. arizonica extract had less IgE reactivity than the native, non-modified extract, while preserving the immunogenic capacity typical for an allergoid. Finally, the SDS-PAGE profile of Cup a 1 allergoid was similar to native Cup a 1 allergen, suggesting the modified C. arizonica extract shows the characteristics of a monomeric allergoid. CONCLUSIONS: The PPT C. arizonica pollen extract shows good in vitro diagnostic potential and its chemically modified form offers the features of a monomeric allergoid. It might therefore lend itself to the development of a product to be administered by the sublingual or oromucosal route for immunotherapy of individuals with cypress pollinosis.

Allergens↗
PubMed1982

Studies on allergen and allergoid preparations from purified timothy (Phleum pratense) pollen extracts. II. Anaphylaxis studies in rats and histamine release from human leukocytes.

In vivo and in vitro allergenic activities of allergen and allergoid preparations from partially purified timothy pollen extract were measured in three different systems. In heterologous PCA titration, the allergen preparation was found to be 32 times more allergenic than the allergoid preparation. By intravenous chaled that treatment of allergen preparations with formaldehyde led to a preparation with the properties of an allergoid. In addition, it was found that the carbohydrate fraction of the refined allergen preparation of timothy a reduction in blood pressure. Thus, the allergen preparation was at least 50 times more potent in inducing systemic anaphylaxis in sensitized rats than the allergoid preparation. In the histamine release assay of grass-sensitive human leukocytes, approximately 1,000 times more allergoid protein than allergen protein was required to achieve 30% histamine release. Although to different degrees, in all three test systems in could be demonstrated that treatment of allergen preparations with formaldehyde led to a preparation with the properties of an allergoid. In addition, it was found that the carbohydrate fraction of the refined allergen preparation of timothy pollen decreased the blood pressure even in nonsensitized animals. The effect of this carbohydrate fraction on blood pressure was immediate but short-lived and immunologically nonspecific.

Allergens↗