Identification of allergens in Dermatophagoides pteronyssinus mite body extract by crossed radioimmunoelectrophoresis with two different rabbit antibody pools

Mimotopes identify conformational B-cell epitopes on the two major house dust mite allergens Der p 1 and Der p 2

House dust mite allergy occurs in 10-20% of the population. Improvement of the present immunotherapy requires detailed knowledge about the structure of the allergens. Mimotopes selected from phage peptide libraries imitate the conformational epitopes of a natural allergen. The aim of our study was to generate epitope mimics for the two major allergens of house dust mite. When the monoclonal anti-Der p 1 and anti-Der p 2 antibodies were used for biopannings, mimotopes were selected which bound also specific IgE from human allergic patients' sera. The conformational matching of these mimotopes on the 3D structure of the natural allergens determined discontinuous epitopes in both cases, representing conformational B-cell epitopes relevant for binding of human IgE. Therefore, these mimotopes are potential candidates for the directed induction of blocking antibodies and epitope-specific immunotherapy of mite allergy.

Analysis of allergens in rat fur and saliva

BACKGROUND

The fur is an important source of allergens in many mammal species, but this source has not been extensively studied in rats. Rat room dust contains high-molecular-weight allergens that have been found to cross-react with fur and its presumed salivary contaminants. The role of rat fur and saliva as a source of respiratory allergens merits further investigation. The objective was to describe the allergens present in the fur and saliva of male rats.

METHODS

Allergen extracts were prepared from the saliva and fur of the pelts from adult male rats. Immunoblotting was used to describe the allergens present in rat fur and saliva with serum from 76 and 25 individuals, respectively.

RESULTS

There was considerable variation between the individuals in the binding of IgE to the separated fur and saliva allergens. Immunoblot analysis identified 23 allergens in rat fur. "Major" allergens were found at the "origin", and at 55, 51, 19, and 17 kDa, and "intermediate" allergens at 74, 67 (probably albumin), and 21.5 (diffuse) kDa. Seventeen salivary allergens were described with "major" allergens at 21.5, 19.5, 19, 18, and 17.5 kDa. Many subjects had IgE to the 67 kDa (56%) and 43 kDa (64%) allergens but the density of staining was weak.

CONCLUSION

Rat fur and saliva are the sources of many allergens. Fur contained five "major" allergens and was a complex source of allergens of relatively high molecular weight (>22 kDa). The most important salivary allergens have molecular weights of less than 22 kDa. Fur is the most probable source of the high-molecular-weight allergens found in rat room dust.

Localization of a major allergen, Der p 2, in the gut and faecal pellets of Dermatophagoides pteronyssinus

BACKGROUND

The house dust mite Dermatophagoides ptronyssinus is one of the most significant indoor sensitizing agents of allergy. Allergen localization may indicate the importance of secreted materials, faeces, and nonexcreted mite body components as allergen sources.

OBJECTIVE

This study attempted to localize the sites and concentrations of Der p 2 in the cryostat sections of D. pteronyssinus using antirecombinant Der p 2 monoclonal antibody.

METHODS

Male and female mites and mite faeces collected separately from both sexes were used. Live mites were embedded and serial cryostat sections for light microscopy were performed. Anti-recombinant Der p 2 monoclonal antibody previously produced by the authors was used. For immunoprobing, mite cryostat sections were incubated in the following antibody-containing solutions: monoclonal antibody against Der p 2 was initially applied to the sections and fluorescent isothiocyanate conjugated antimouse immunoglobulin G was reacted as the secondary antibody. The faecal pellets were treated the same as described above.

RESULTS

Immunofluorescent probing of cryostat sections with the monoclonal antibody showed labelling of the gut lining, gut contents and defecated faecal pellets. No other internal organs were identified as positively labelled.

CONCLUSION

This study suggested that a major allergen, Der p 2, found in the house dust mite D. pteronyssinus is derived from the digestive tract and concentrated in the faeces.

House dust mite-induced sensitivity in mice

Sensitivity induced by house dust mite (HDM) extract in mice was investigated in this study. Sensitized B10.RIII mice (H-2r background) had T-cell proliferative responses to HDM extract in vitro and an HDM-specific IgE response. When mice were immunized by injection and intranasal inhalation with HDM extract, a histologic study showed eosinophils and mononuclear cell infiltration in the lung tissue and bronchial wall. Tcr alphabeta-positive cells were also found in the cell infiltration area of the lung lesions. In the control mice that were immunized by injection or intranasal inhalation (but not both), we did not observe cell accumulation in the lung tissue or in the bronchial wall. Epitope studies suggest that T cells recognize multiple epitopes. Molecular analysis of these HDM-specific T-cell hybridoma clones suggest that T-cell receptor use is restricted to members of the V alpha 8 and Vbeta 6 subfamilies.

Characterization of allergenic components from house dust mite Dermatophagoides siboney. Purification of Der s 1 and Der s 2 allergens

BACKGROUND

Allergic reactions to house dust mites of the genus Dermatophagoides play an important role in the pathogenesis of asthma and other atopic diseases. Dermatophagoides siboney has been described as a species from Cuba. Together with D. pteronyssinus and Blomia tropicalis, it is frequently found in house dust from homes of asthmatics.

OBJECTIVES

The aim of this study was to investigate the allergenic composition from the house dust mite D. siboney.

METHODS

The characterization of D. siboney extract was performed by SDS-gPAGE and immunoblotting. Purification of individual components was performed by affinity chromatography.

RESULTS

At least 16 components between 13 and 98 kDa stained by Coomassie Blue were found. Using a panel of 35 sera from atopic mite sensitive patients 13 components reacted to different extent with patient IgE. Two components, 25 and 14 kDa, bound to specific IgE strongly and frequently, i.e. 80 and 91% of the patients, respectively. Affinity chromatography using crossreacting monoclonal antibodies to group 1 and 2 allergens resulted in purified preparations of 25 and 14 kDa proteins, which showed IgE-binding with the majority of the human sera when tested by immuno-dot.

CONCLUSION

Based on the IgE binding profile of D. siboney and on the capacity to react with crossreacting monoclonal antibodies for groups 1 and 2, it is proposed to name these two allergens, 25 and 14 kDa, Der s 1 and Der s 2, respectively.

Immunogenicity and antigenicity of synthetic peptides derived from the mite allergen Der p I

As an immunogen must contain both B- and T-cell epitopes, small peptides are usually reported as non-immunogenic unless coupled to a protein carrier. In this study, the immunogenicity of the Der p I synthetic uncoupled peptides (p52-71, p89-104, p117-133 and p176-187) previously reported as B-cell epitopes, was evaluated. Different schedules of immunization were used. Results indicated that by using the Vaitukaikis' method three injections of the same peptide without protein carrier was sufficient to induce an specific anti-peptide IgG antibody response (evaluated by ELISA). Indeed, the 16-20 amino-acid long peptides p52-71, p117-133 and p89-104 were revealed highly immunogenic in rabbits. Furthermore anti-peptide p52-71 and p117-133 antibodies were shown by Western-blotting or by neutralization assay to recognize the Der p I molecule either in denaturated or native form as well as Der f I (major allergen of Dermatophagoides farinae). Finally, taking into account the location of Der p I-derived peptides in the three-dimensional model of Der p I, the antigenicity and immunogenicity of peptides were discussed.

Molecular cloning of a house dust mite allergen with common antibody binding specificities with multiple components in mite extracts

Plaque radio-immuno assay has been used to isolate an IgE-binding clone from a lambda gt11 library of Dermatophagoides pteronyssinus cDNA. The clone HD6 contained DNA encoding a 215 residue protein which contained a predicted 17 amino acid residue leader sequence, no cysteines and a single N-glycosylation site. The 198 residue mature protein would have a predicted MW of 22,177 D. No homologues were found in searches of the data banks. Sera from 14/38 allergic children reacted strongly with the polypeptide produced by the clone (37%). Skin tests showed reactivity in 16/30 (53%) allergic patients and 0/10 of controls. Affinity purification of rabbit antibodies with the clone showed that antibodies to the polypeptide had specificities to multiple products in mite extracts corresponding to components of Mr 29, 27 and 24 K by Western blotting. Absorption studies of IgE in allergic serum indicated further entities at 13 and 11.5 kD. It is proposed to name this allergen Der p VII.

Characterization and partial purification of the Croatian national standard Dermatophagoides pteronyssinus allergen extract

Lyophilized Dermatophagoides pteronyssinus (Der p) allergen extract (AE) and partially purified Der p extract (PAE) were prepared and characterized. Partial purification of AE was performed by gel filtration on Sephadex G-100 and Sephacryl S-300. Crossed immunoelectrophoresis (CIE) disclosed the same precipitating lines in AE and PAE preparations. The relative potencies of AE and PAE were determined and compared with the WHO International Standard for Der p by the RAST inhibition method. The potencies were 6.5 x 10(5) IU and 1.5 x 10(6) IU, respectively. Biologic standardization by quantitative skin testing was performed with AE (20 selected patients) and PAE (12 patients). Median Ch was calculated by linear regression analysis (log-log model). One ampoule of AE contained 65,300 BU and 1 ml (vial) of PAE contained 166,000 BU. Der p AE could serve as a croatian national standard for further production of Der p allergenic extracts.

The effects of season, climate, and air-conditioning on the prevalence of Dermatophagoides mite allergens in household dust

BACKGROUND

Clinical evidence reveals a strong relationship between dust mite allergen levels and asthma. This study suggests the relative importance and interactions among factors that influence mite allergen levels in human dwellings.

METHODS

Dermatophagoides pteronyssinus allergen (Der p I) and D. farinae allergen (Der f I) were measured in 536 dust samples collected from 424 homes across the United States.

RESULTS

There were distinct seasonal fluctuations of Der p I and Der f I. Der p I rapidly increased to peak in July then gradually decreased through October. Der f I slowly rose to peak later, around September, before declining. Different climates in regions of the United States had no significant affect on the quantity of Der p I or Der f I. However, regional climate differences seemed to influence the prevalence of either D. pteronyssinus or D. farinae. Air-conditioning significantly reduced (p < 0.001) Der I mite allergens detected in the dust samples, and a tendency existed for Der f I to be higher than Der p I in air-conditioned homes. There was a significant (p < 0.01) interaction between air-conditioning and seasons. The most dramatic affect was observed during the summer months, the cooling season, from approximately May to September.

CONCLUSIONS

These findings show that distinct seasonal fluctuations exist of D. pteronyssinus and D. farinae mite populations, and suggest that differences in the microclimate within homes may have a dramatic affect on Dermatophagoides mite populations.

Specific histamine release capacity of peptides selected from the modelized Der p I protein, a major allergen of Dermatophagoides pteronyssinus

Dust mite allergens are considered as a major cause of allergic disease and as a risk factor for asthma. Der p I, a 222 amino-acid residue globular glycoprotein, is one of the major allergens from Dermatophagoides pteronyssinus (Dpt) mites. In this study, we have used predictive conventional algorithms (i.e. hydrophilicity, mobility, accessibility) and a three-dimensional model of Der p I derived from comparison to actinidin and papain to select continuous amino acid sequences as potential B cell epitopes. Four peptides, 52-71, 117-133, 176-187, 188-199 were synthesized. Their antigenic reactivity was investigated, mainly by measuring their capacity to induce in vitro histamine release. Results indicated that only Dpt-sensitive patients react specifically to Der p I-derived peptides and more frequently to 52-71 and 117-133. For each peptide, the intensity of response was dependent on the patient tested and on the peptide concn. The capacity of peptides to induce histamine release was demonstrated to be correlated with the serum level of anti-Der p I IgE (r = 0.86; p less than 10(-2)). Taken together these data emphasize, in Dpt-sensitive patients, the heterogeneity of the specific response to synthetic Der p I-derived peptides and underline the possible variety of epitopes belonging to the allergen Der p I.

Isolation of Der pI, the Dermatophagoides pteronyssinus major mite allergen, from a crude mite culture extract, purification by ion-chromatography, and comparison between the material obtained and a cDNA-coded Der pI

A high degree of purity is a prerequisite for an allergen preparation to be suitable for clinical diagnosis and therapy. A pure allergen can easily be obtained from a crude mite culture extract by using an immunosorbent prepared with highly specific monoclonal antibodies or from a cDNA-coded material. However, up to now none of these methods has been performed on a process scale. Here large-scale purification is defined as a process in which a crude Dermatophagoides pteronyssinus mite culture extract is essentially fractionated by acetone and ammonium sulphate precipitations followed by anion-exchange high-performance liquid chromatography. A high yield of a very pure Der pI allergen is obtained during the first isocratic run, as shown by sodium dodecylsulphate-polyacrylamide gel electrophoresis, capillary electrophoresis, chromatofocusing and a two site monoclonal antibody enzyme-linked immunosorbent assay. Microsequencing revealed that the 25-residue sequence obtained is entirely in agreement with the sequence derived from the cDNA of Der pI.

Identification of allergenic epitopes on Der ⨍ I, a major allergen of Dermatophagoides farinae, using monoclonal antibodies

The antigenic and allergenic structure of Der f I, a major allergen of the house dust mite Dermatophagoides farinae (Df) was investigated by means of a panel of 11 selected monoclonal antibodies (mAb) obtained from BALB/c mice immunized with purified Der f I. The species specificity of these mAb, tested with Der f I and Der p I--the homologous allergen from Dermatophagoides pteronyssinus--was generally restricted to Der f I since 10 out of 11 mAb reacted only with this allergen. Epitope specificity of the mAb was determined by both competitive inhibition and sandwich ELISA experiments. The results indicated the presence of at least four non-overlapping, non-repeated antigenic sites on Der f I, which were recognized by one or several mAb (sites A, B, C and D). Comparative epitope specificity studies between human IgE antibodies and mice mAb were performed, on sera and basophils of Df sensitive patients, using different inhibition assays (ELISA and histamine release experiments). The degree of inhibition varied between the patients and upon the assay design. Most of the mAb tested were found to significantly inhibit the binding of human IgE to Der f I (p less than 0.01) when compared with Der p I specific mAb as a control. The mAb reacting with site A was found to be the most potent inhibitor, presenting a mean inhibition of up to 56% in ELISA as well as in histamine release experiments. The results show that both human IgE antibodies and mAb can be directed against identical or closely related epitopes of Der f I. Therefore anti-Der f I mAb constitute immunologic probes in further allergenic epitope and peptide analysis of this major mite allergen.

IgE binding structures of the major house dust mite allergen DER P I

The group I allergens Der p I and Der f I are potent allergens of mites from the genus Dermatophagoides. IgE radioimmune dot blots and immunoabsorption with recombinant peptides have been used to define areas of antigenicity. Four linear binding regions comprising residues 15-33, 60-80, 81-94 and 101-111 were found in the N terminal domain and one, 155-187, in the C-terminal domain, but direct evidence for their discontinuous nature is shown. Firstly, the binding activity of residues 60-80 required either C- or N-terminal flanking sequences to express reactivity and secondly a discontinuous determinant was directly demonstrated by the two non-overlapping peptides 53-99 and 101-154 which significantly cross absorbed specificities to one another. This also indicates considerable homogeneity in the antibodies recognising these peptides. The IgE binding peptides could be located to equivalent residues on the X-ray crystallographic structure of the homologous proteins actinidin and papain. The residues 81-94 and 101-111 which gave strong reactivity were located on a flexible loop connecting the domains and represent areas in which synthetic peptides could be expected to retain activity.

House dust mite-derived amylase: allergenicity and physicochemical characterization

Amylase activity was found in extracts of both Dermatophagoides pteronyssinus whole mite (0.16 U/mg) and spent growth medium (0.01 U/mg) but not in unused growth medium. It was also detected in all extracts of house dust obtained from mattresses (n = 20; geometric mean, 1.95 U/gm) and in 18 extracts of dust obtained from lounge room carpets (n = 20; geometric mean, 0.54 U/gm). Although the origins of amylase in dust are unclear, enzyme activity correlated with mite counts (n = 40; r = 0.35; p less than 0.05) and Der p I concentrations (r = 0.41; p less than 0.01). Mite amylase was purified from spent growth medium by affinity chromatography, gel filtration, and chromatofocusing. It was physicochemically similar to mammalian amylase with regard to molecular weight (60,000), charge heterogeneity (isoelectric point, 5 to 7) and the capacity to bind to an organomercurial affinity matrix. The optimum pH for enzymatic activity was revealed to be 6.4. IgE immunoblot studies demonstrated that the enzyme was allergenic and that its expression was dependent on the integrity of intrachain disulfide bonds. Sera from 25% of mite-allergic children and 46% of mite-allergic adults contained specific IgE to mite amylase. IgE to amylase was associated (p less than 0.01) with increased concentrations of total mite-specific IgE determined with a direct RAST assay.

Sequence analysis of cDNA coding for a major house dust mite allergen, Der f I

A cDNA clone coding for Der f I, a major allergen from the house dust mite Dermatophagoides farinae has been isolated and sequenced. It codes for a putative 18-residue signal peptide, an 80-residue proenzyme region, and a 223-residue mature protein with a derived molecular weight of 25,191. The deduced amino-acid sequence shows significant homology to other cysteine proteases in the proregion as well as in the mature protein. Sequence alignment of the mature Der f I protein with the homologous allergen Der p I from the related mite D. pteronyssinus revealed a high degree of homology (81%) between the two proteins, as predicted by previous sequencing at the protein level. In particular, the residues comprising the active site of these enzymes and the cysteine residues were conserved. A potential N-glycosylation site was present at an equivalent position in both mite allergens. It is anticipated that the availability of recombinant Der f I will facilitate epitope mapping studies and studies of T-cell function in mite allergy by providing high levels of pure allergen.

Comparison of diversity and function of house dust mite-specific T lymphocyte clones from atopic and non-atopic donors

Panels of CD4+CD8- T lymphocyte clones (TLC), specific for house dust mite Dermatophagoides pteronyssinus (Dp) proteins, were generated from the peripheral blood of an atopic Dp-allergic donor (AD), suffering from severe atopic dermatitis, and a histocompatible non-atopic donor (NAD). We studied the diversity of TLC within these two panels in search for the possible occurrence of dominant clone types with properties that might be characteristic for the atopic or non-atopic state. TLC with specificities for at least four different Dp proteins were found within the panel from AD "L" and for at least three different Dp proteins within the panel from NAD "K". In addition, both panels showed a considerable but comparable restriction diversity within HLA-DR. Despite the diversity within the panels, all Dp-specific TLC from AD were found to produce IL 4, after HLA class II-restricted Dp-specific stimulation, whereas the TLC from NAD produced no or only minimal amounts of this lymphokine. Only supernatants from stimulated AD TLC could induce IgE secretion by B cells from NAD. Conclusively, these observations do not give evidence for the occurrence of an abnormal Dp-specific T cell repertoire in AD, but rather suggest aberrant secretion of the IgE-inducing lymphokine IL 4 by CD4+ Dp-specific T cells from AD.

Recent progress in mite allergen immunochemistry

The successful purification of several mite allergens within the last few years has considerably enhanced our understanding of mite allergen immunochemistry. The role of these glycoproteins in stimulating human IgE ab and their role as immunogens in mice and rabbits has been studied extensively in a number of laboratories worldwide. In particular, purified allergens have facilitated the production of murine IgG Mabs that have been used to purify mite allergens by affinity chromatography; to investigate the diversity of antigenic sites on purified allergens; and to develop Mab based immunoassays for measuring allergen concentrations in dust samples and extracts. Full amino acid sequencing of several mite allergens is now in progress together with efforts to identify antigenically important peptide fragments. Such investigations are aimed to further increase our knowledge of humoral and cellular immune responses at the molecular level. For years, pollen counts have been used to judge airborne pollen allergen levels and to predict, in turn, the severity of symptom days for patients with hay fever. In contrast, simple methods for measuring dust allergens (e.g., mite allergen) have not been available. The development of Mab immunoassays, which can be converted from radiolabeled to enzyme labeled or fluorescence labeled assays, should provide rapid and quantitative measurements of specific mite allergen levels in house dust. Not only can such measurements provide useful clinical information in judging the exposure of patients to mite allergen, but the effectiveness of allergen avoidance regimes can be monitored objectively. By measuring the concentration of specific allergens in extracts, these assays could significantly improve efforts to standardize extracts used for diagnosis and treatment.

Prospective study on immunologic changes induced by two different Dermatophagoides pteronyssinus extracts prepared from whole mite culture and mite bodies

Twenty-four children with bronchial asthma and hypersensitivity to Dermatophagoides pteronyssinus by skin titration, specific serum IgE, leukocyte histamine release, and bronchial challenge test were selected for immunotherapy with two partially purified mite extracts. On the basis of age and allergen-specific IgE responses, patients were randomly divided for treatment with either an extract prepared from whole mite culture (WMC) or from purified mite bodies (MB). The content of major allergens was quantified for both extracts. The allergen dose administered during immunotherapy was increased up to the highest tolerated dose. The mean cumulative dose of Der p I was 98.9 micrograms for the WMC-treatment group and 76.7 micrograms for the MB-treatment group. Small, but statistically significant, decreases in RAST and crossed radioimmunoelectrophoresis responses to major allergens were recorded after 2 years of treatment. A small increase in specific IgG1 and a large persistent increase in specific IgG4 was recorded in both groups. There was a significant decrease in allergen-specific bronchial sensitivity, skin reactivity, and leukocyte sensitivity in both treatment groups. Between both groups, changes in the different parameters were not significantly different. Our data indicate that immunotherapy with both partially purified house dust mite extracts, WMC, and MB leads to a decrease in allergen-specific IgE responses and induce a response in specific IgG4. Both extracts are comparable in modulating leukocyte and skin sensitivity, as well as bronchial reactivity to mite allergens.

Allergy to rabbits. II. Identification and characterization of a major rabbit allergen

Quantitative immunoelectrophoretic techniques have been used to study the antigenic components found in extracts of dust collected from rabbit housing areas. To determine the possible source of these antigens, comparisons have been made to rabbit saliva, urine, fur and dander. Specific antisera for the rabbit extracts were raised in guinea pigs. One major component of the dust (Ag Rl) was also found in large amounts in saliva, slightly less in fur and in only minimal amounts in urine and dander. Crossed radioimmunoelectrophoresis (XRIE) of the dust, performed with sera from 14 rabbit allergic individuals who were RAST positive to rabbit saliva, urine and dust identified four IgE-binding constituents. Individual responses varied but all sera reacted with Ag Rl, identifying this as a major rabbit allergen. Dust RAST inhibition studies with rabbit dust, saliva and urine indicated saliva to be closely related to the dust. Ag Rl is a glycoprotein which appears to be very heterogeneous in nature. It produced a broad biphasic precipitin peak on immunoelectrophoresis and eluted from Sephacryl S-200 gel filtration over the molecular weight range 30-50 Kd, although a molecular weight of 17 Kd was indicated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and gradient gel electrophoresis. The RAST inhibition results and the antigenic similarity of saliva to the dust suggest this to be the most likely source of the major rabbit allergen, Ag Rl.

Sequence analysis of cDNA coding for a major house dust mite allergen, Der p 1. Homology with cysteine proteases

A cDNA clone coding for Der p 1, a major allergen from the house dust mite Dermatophagoides pteronyssinus, has been sequenced. It codes for a 222 residue mature protein with a derived molecular weight of 25,371 and contains 1 potential N-glycosylation site. In addition, the cDNA appears to code for a 13 residue proregion, and an incomplete signal peptide. The deduced sequence shows a high degree of homology with animal and plant cysteine proteases, particularly in the region of the contact residues making up the active site. Southern analysis of genomic DNA indicates that the allergen is coded by a noncontiguous gene. These data will now facilitate epitope mapping studies.

ELISA method for measurement of airborne levels of major laboratory animal allergens

Three types of air-sampling apparatus (the Air-Sentinel, Burkard Personal Sampler and Casella Personal Sampler) were compared for their use in sampling the air in situations where individuals are exposed to laboratory animals, and a cascade impactor was used to determine the sizes of particles carrying the allergens under investigation. An ELISA, using monospecific antisera raised to selected major allergens of the mouse, rat and rabbit, i.e. mouse Ag 1 (mouse urinary prealbumin), rat Ag 4 (rat urinary prealbumin) and rabbit Ag R1, was developed to assay the extracts obtained from the samplers. This ELISA system was able to detect greater than 5 ng/m3 of allergen in sampled air. The rat and mouse allergens were shown to be carried mainly on particles of 6-18 micron, whereas the rabbit allergen was also found on particles of 2 micron and smaller. Allergen levels correlated well with the number of animals present in the room and the degree of activity during sampling. A protective filtered-air hood, when worn during surgical operation procedures, was shown to reduce effectively the level of rat allergen breathed by an individual.

Comparison of Dermatophagoides pteronyssinus allergens from culture medium extract and whole body extract by using the same probe of pooled human serum

Two distinct allergens of Dermatophagoides pteronyssinus were isolated from culture medium extract and whole body extract monitored by the same probe of pooled human serum and compared. IgE-binding activity of allergens from the two sources was detected by microplate-ELISA with the same probe throughout the column chromatography. An allergen obtained from culture medium extract (Ag-CME) had a molecular weight of 27,000 by SDS-polyacrylamide gel electrophoresis (PAGE) and two isoelectric point ranges, pI 4.0-4.7 and 5.9-6.8. Another allergen from whole body extract (Ag-WBE) had a molecular weight of 15,000 by SDS-PAGE and an isoelectric point range, pI 4.8-5.3 Ag-CME and Ag-WBE are probably the same allergens as antigen P1 and DpX, respectively.

Investigations of culture medium-free house dust mites. III. Antigens and allergens of body and fecal extract of Dermatophagoides farinae

Crossed immunoelectrophoresis (CIE) and crossed radioimmunoelectrophoresis (CRIE) were used to characterize antigens (Ags) and allergens derived from Dermatophagoides farinae (DF) culture media-free mite body and mite fecal matter extracts. CIE of DF body and DF feces extracts revealed the presence of 35 and 20 Ags, respectively. CRIE experiments demonstrated IgE binding by 14 and seven DF body and DF feces Ags, respectively, when CIE gels were incubated with reference sera from clinically mite-sensitive patients. Binding of specific IgE to the various Ags in the two extracts varied significantly both in frequency and in strength from patient to patient and within the same patient's serum. Sera from some patients demonstrated IgE binding predilection for specific DF body Ags, whereas other sera exhibited greater binding preference for DF feces Ags. Homologous, heterologous, and intermediate gel CIE and CRIE clearly demonstrated that DF bodies and DF feces share some common Ags or epitopes, but the two different extracts also were quantitatively different. Some Ags and allergens originate from mite body material and are not present in mite feces. These results indicate that only extracts containing high concentrations of both body and fecal allergens should be used in clinical testing and therapy.

Investigations of culture medium-free house dust mites. IV. Cross antigenicity and allergenicity between the house dust mites, Dermatophagoides farinae and D. pteronyssinus

Heterologous crossed immunoelectrophoresis (CIE) analysis demonstrated that Dermatophagoides pteronyssinus body and D. farinae body extracts contained up to 21 cross-reacting antigens (Ags). Incubation of CIE gels with two mite-sensitive individual sera and a serum pool of mite-sensitive patients indicated that up to nine cross-reacting Ags bound mite-specific IgE on crossed radioimmunoelectrophoresis and were common allergens. Likewise, heterologous CIE analysis of D. pteronyssinus feces and D. farinae feces extracts demonstrated approximately 13 cross-reacting Ags. Up to eight of these cross-reacting fecal Ags bound mite feces-specific human IgE. Additional cross antigenicity and allergenicity was evident between body extract of one species and feces extract of the other species. The amount of specific IgE binding to cross-reacting Ags in interspecific extracts varied both between and within individual sera. Different cross-reacting Ags contained potent allergens, and these varied from patient to patient. Also of major significance was the fact that body and fecal extracts of each species contained Ags and allergens that were unique and species specific.

Allergy to mice. I. Identification of two major mouse allergens (Ag 1 and Ag 3) and investigation of their possible origin

An extract of dust from the outlet filters of a mouse isolator was used as a basis for determining the source of inhalant allergens for subjects sensitive to this species. The antigenic components, identified by crossed immunoelectrophoresis (XIE), were compared to those found in extracts of other mouse-derived source materials, i.e. urine, fur, dander and saliva. Of the eight dust components, one (Ag 1) was identified as antigenically identical to the major urinary pre-albumin whilst the others were detected in fur, and to a lesser extent dander and saliva. None of the dust antigens was detected as a component of food or bedding. Crossed radio-immunoelectrophoresis (XRIE), performed using sera from a group of fifteen mouse-allergic subjects (positive by RAST to mouse extracts), identified seven of the dust antigens as IgE-binding components. Antigens 1 and 3 were reactive with all the sera tested and have, therefore, been termed the 'major' allergens. Varied responses were obtained to the other 'minor' antigens. Ag 1 (urinary pre-albumin) and Ag 3 were detected in all samples of mouse dust studied. RAST and RAST inhibition also indicated the presence of urinary pre-albumin. These findings suggest that the major mouse inhalant allergens may be derived predominantly from urine and secretions originating in the skin and present on the fur.

Does natural sensitisation in eczema occur through the skin?

The specificities of serum IgE for the faecal and body antigens of the house-dust mite, Dermatophagoides pteronyssinus, were compared in 69 children with various combinations of asthma, eczema, and/or rhinitis. The concentration of IgE antibodies to the mite body was higher in those with eczema than in those with asthma, but the concentrations of IgE antibodies to the faecal allergen were not significantly different. The ratio of the serum concentration of anti-mite-body IgE to anti-faecal IgE was significantly greater in the children with eczema than in the children with asthma. The results in 4 subjects with rhinitis (2 with and 2 without eczema) support the view that IgE antibodies to the mite body are characteristic of eczema. Sensitisation to mite body and mite faecal particles may occur by different processes; the allergens of mite bodies may penetrate the skin, whereas faecal allergen may enter the body by other route(s).

Allergy to guinea pigs: II Identification of specific allergens in guinea pig dust by crossed radio-immunoelectrophoresis and investigation of the possible origin

An extract of dust from the air-vent filters of a room housing guinea pigs was analysed by quantitative immunoelectrophoretic procedures and compared with extracts of various materials derived from guinea pigs. Crossed radio-immunoelectrophoresis (CRIE) of the dust, performed with sera from twenty asthmatic patients who were positive by skin testing and RAST to guinea pig extracts, identified fourteen IgE-binding constituents. Although responses varied, most sera reacted with four particular allergens, antigens 2, 3, 10 and Sl. The numbers of allergens recognized by individual patients correlated with the RAST score, but not with total serum IgE. All seventeen dust constituents detected by crossed immunoelectrophoresis (and all four major allergens), were also present in extracts of guinea pig dander, fur, saliva and urine; several of these components were absent in an epithelial extract, and there were even less in preparations of shaved pelt, serum or faeces. None of the dust extract antigens were detected in materials used in animal husbandry, dust samples from rooms without guinea pigs, or a D. pteronyssinus extract. These findings suggest that inhalant allergens may be derived predominantly from material shed from the guinea pig coat after contamination with saliva, and possibly to a lesser extent, urine.

Purification of two allergens from Dermatophagoides pteronyssinus using monoclonal antibodies

Fractionation of soluble extracts from the house dust mite Dermatophagoides pteronyssinus (DP) by SDS-PAGE and crossed immunoelectrophoresis (CIE) revealed at least fifty distinct protein components. Western blotting and crossed radioimmunoelectrophoresis (CRIE) indicated that fewer than one quarter of these components were allergens as determined by their ability to bind IgE from allergic individuals. Following immunization with a crude extract, two monoclonal antibodies were raised against distinct components which exhibited IgE binding capacities in Western blot and CRIE. Affinity chromatography using these monoclonal antibodies yielded components which elicited positive skin test reactions in patients allergic to DP.

Activity of allergenic proteins from Dermatophagoides pteronyssinus. Comparison of crossed radioimmunoelectrophoresis (CRIE) and histamine release from washed leukocytes

Two purified allergens from Dermatophagoides pteronyssinus, Dp 42 (identical to P1) and Dp X were studied for their ability to induce histamine release from washed leukocytes and to bind to IgE antibodies from the serum of 27 mite-sensitive children. Almost all patients were demonstrated to be sensitive to both proteins by both assays. Dp 42 was found to have the highest allergenic activity, releasing histamine from leukocytes at a median concentration 10 times lower than for Dp X. There was a positive correlation between basophil sensitivity to both proteins and allergen specific serum IgE concentrations.

Immunochemical and biological characterization of a mugwort (Artemisia vulgaris) pollen extract

A reference extract of mugwort pollen (Artemisia vulgaris) was characterized by crossed immunoelectrophoresis (CIE), crossed radio immunoelectrophoresis (CRIE) and quantitative skin prick test (QSPT). CIE revealed that the extract contained at least 42 distinct antigens of which 24 migrated towards the anode and 18 towards the cathode at pH 8.6. A CRIE analysis of the crude mugwort pollen extract, performed with sera from 29 mugwort-allergic patients, showed that 10 antigens may be considered allergens; one was classified as a major allergen, five as intermediate allergens, and four as minor allergens. The QSPT performed on the same 29 allergic patients established that 17.4 micrograms lyophilised reference mugwort pollen extract per ml had a biological potency of 1 HEP (histamine equivalent by prick test).

Antigens and allergens from the common house dust mite Dermatophagoides pteronyssinus. Part II. Identification of the major IgE-binding antigens by crossed radioimmunoelectrophoresis

Crossed immunoelectrophoresis demonstrated 51 antigens in a water-soluble extract of the house dust mite Dermatophagoides pteronyssinus. Autoradiography demonstrated that 11 of the antigens bound IgE antibodies in the sera of house dust mite-allergic patients. IgE antibodies in 23 different sera reacted with from one to eight antigens. On the basis of Lowenstein's (1978) definition of a "major allergen," two of the antigens, numbers one and 36 would be described as "major allergens." Apart from antigen number 36 that has already been demonstrated to be an important allergen in patients allergic to D. pteronyssinus, the clinical importance of the other 10 IgE-binding antigens has yet to be assessed. Reasons against use of the term "major allergen" and its replacement with the title "clinically important allergen" are advanced.

A reference allergen preparation of the house dust mite D. pteronyssinus, produced from whole mite culture--a part of the DAS 76 study. Comparison with allergen preparations from other raw materials

A D. pteronyssinus whole culture allergen preparation contained 49 antigens as revealed by crossed immunoelectrophoresis (CIE), using polyspecific rabbit antibodies. Crossed radio-immunoelectrophoresis ( CRIE ) with sera from 30 patients revealed nine allergens, antigens 42, X, Y and 23 (in rank order) showing the most frequent and intense IgE-uptake. Nine antigens originated from the culture medium (human dander + yeast), but none of these gave rise to specific IgE-uptake. Extremely few and weak reactions were observed in radioallergosorbent (RAST) with 129 sera, using media extracts on the discs. Purified mite body extract (PMB) contained less ag 42 and more ag Y and ag 23 than whole mite culture extract ( WMC ), whereas an acetone-extracted mite excreta preparation (AML) contained 5 times more ag 42, but was devoid of ag Y and ag 23. Ag X was present in all preparations. The RAST-inhibitory potency of PMB was best correlated with the content of ag X. Preparations with properties similar to WMC and PMB were judged as suitable for clinical application.