Biomedical subjects

K Y Chua

Publications and source records attributed to K Y Chua.

At least 37 records · Page 2Linked to original sources

PubMed2001

Immunochemical characterization of edible bird's nest allergens.

BACKGROUND: We have previously described anaphylaxis induced by edible bird's nest (BN) and demonstrated that this condition is IgE mediated. OBJECTIVES: This study aimed at describing the immunochemical properties of the BN allergens. Comparative studies between 3 commercially available sources (according to the country of origin) of BN were also made. METHODS: Crude extracts of commercially available processed BN from Sarawak (Malaysia), Thailand, and Indonesia and fresh unprocessed BN from the caves of Sarawak were obtained by means of aqueous extraction. Specific IgE toward these sources were determined by using fluorescence allergosorbent tests (FASTs). Cross-reactivity studies between the 3 sources of commercially available processed BN were carried out by means of FAST inhibition. Immunochemical characterization by means of IgE immunoblot, periodate treatment, and heat stability studies were carried out on fresh unprocessed BN from Sarawak. RESULTS: Serum from allergic patients showed differences in IgE binding to the 3 sources of commercially available BN, with the highest levels of specific IgE recorded with the Sarawak source (P <.0001). Of these, only the Sarawak and Thailand sources showed considerable cross-reactivity. Further work on the unprocessed fresh Sarawak source identified a putative 66-kd major allergen containing several isoforms. Periodate treatment resulted in loss of IgE binding. Despite a progressive decline in the molecular weights of allergens on SDS-PAGE with increasing periods of boiling, IgE binding, as assessed by means of FAST, was not affected. N-terminal sequence of the major putative allergen (66 kd) showed homology to a domain of an ovoinhibitor precursor in chicken (SWISS-PROT accession No. P10184). CONCLUSIONS: We have described the immunochemical properties of BN allergens. Edible BN from different sources are allergenically dissimilar. The putative major allergen is a 66-kd protein.

Adolescent↗

PubMed2001

cDNA cloning and expression of Blo t 11, the Blomia tropicalis allergen homologous to paramyosin.

Blomia tropicalis is an important mite species in many parts of the world and the most predominant mite species in tropical countries. The prevalence of sensitization to this species has probably been underestimated because commercial extracts are largely unavailable. Identification and characterization of B. tropicalis allergens is an important step toward understanding the role of this species in allergic sensitization and could provide appropriate reagents for diagnostic and therapeutic procedures. This paper describes the isolation, sequence analysis, expression and allergenicity of a cDNA gene coding for a B. tropicalis allergen with homology to paramyosin, a high-molecular-weight allergen previously identified in Dermatophagoides farinae. The full-length Blo t 11 cDNA gene was isolated by cDNA library screening, 5'-rapid amplification of cDNA ends and long-distance PCR. Sequence analysis was performed with a combination of CLUSTAL W, CGC and BLAST program packages. The cDNA gene was expressed as a GST fusion protein in Escherichia coli and purified by affinity chromatography using the glutathione Sepharose column. Allergenicity of the rBlo t 11 was tested by human IgE dot blot immunoassay. Blo t 11 is a 3,111-bp cDNA gene with a 2,625-bp open reading frame coding for an 875-amino acid protein, exhibiting significant homology with different invertebrate paramyosins. The human IgE dot blot immunoassay showed that the rBlo t 11 reacted positively to 52% (33/63) of sera from asthmatic patients. Blo t 11 is the homolog of Der f 11 exhibiting potentially important allergenic activity.

Allergens↗

PubMed2000

Protein sequence analysis and mapping of IgE and IgG epitopes of an allergenic 98-kDa Dermatophagoides farinae paramyosin, Der f 11.

BACKGROUND: A 98-kDa mite paramyosin (Der f 11) from Dermatophagoides farinae (Df) is highly allergenic, and its cDNA (Df642) has been cloned. This paper describes the sequence characteristics and the mapping of the immunodominant human IgE and IgG epitopes of Der f 11. METHODS: The protein sequence analysis was performed with a combination of FASTA, GCG, and CLUSTAL W computing packages. The whole cDNA insert and its PCR-derived DNA fragments were generated and expressed in E. coli. These overlapping recombinant peptides (F1 to F5) were used for B-cell epitope mapping with 18 mite-allergic sera by dot immunoassays. RESULTS: Df642 cDNA encodes a partial sequence that contains the 2nd to 26th 28-residue repeats and lacks the N-terminus and the C-terminus. The sequence identity of Der f 11 with other known paramyosins is 34-60%. The dominant IgE epitopes are located in peptides F1 and F4, whereas the dominant IgG epitopes are located in peptides F1 and F2. These peptides are more reactive than whole rDf642. CONCLUSIONS: Mite paramyosin is very similar to other known paramyosins. The human IgE and IgG epitopes are scattered throughout the entire molecule. Data also indicate the presence of unique IgE and IgG epitopes in Der f 11.

Allergens↗

PubMed2000

HLA DPB1*0201 allele is negatively associated with immunoglobulin E responsiveness specific for house dust mite allergens in Taiwan.

BACKGROUND: House dust mite (HDM) Dermatophagoides pteronyssinus is the most important source of indoor allergens that cause allergic diseases in Taiwan. We prepared purified HDM allergens (Der p 1, Der p 2 and Der p 5) to detect allergen-specific immunoglobulin (Ig) E responsiveness among a large number of test subjects. The robust genetic typing system for HLA class II genes also facilitated the study on association of HLA and allergic response toward HDM. OBJECTIVE: This study intended to investigate the association between HLA class II alleles and the IgE responsiveness to the major allergens from HDM, D. pteronyssinus. METHODS: Two hundred and forty-eight subjects were selected for HLA association study. Plasma HDM allergen (Der p 1, Der p 2, Der p 5) -specific IgE and Der p 2-specific IgG antibodies were detected by ELISA, while HLA class II -DRB1, -DQA1, -DQB1, -DPB1 genetic polymorphism was determined by polymerase chain reaction/sequence-specific oligonucleotide probe hybridization (PCR/SSOPH). Statistical comparison of the allelic distribution of each HLA class II genes among the individuals with/without HDM allergen-specific IgE and IgG antibodies were performed. RESULTS: There was no significant association between HLA DRB1, DQB1, DQA1 alleles and HDM-specific IgE responsiveness noted. Only DRB1*0803 and the linked DQA1*0103 alleles showed positive association with Der p 5-specific IgE responsiveness. However, we found that HLA-DPB1*1301 predisposed subjects to IgE responsiveness to HDM Der p 5. HLA DPB1*0501 was weakly associated with the IgE responsiveness to HDM Der p 1 and Der p 5. There was a strong negative association between the HLA-DPB1*0201 allele with IgE responsiveness to Der p 1 (OR: 0.30, P </= 0.0001, P </= 0.0007, Pc </= 0.010). CONCLUSION: We clearly observed the association between HLA DPB1 alleles and specific IgE responsiveness to HDM major allergens. The molecular mechanism of HLA-DPB1*0201 involvement in protecting subjects from HDM-specific IgE responsiveness awaits further investigation.

Adult↗

PubMed2000

Edible "bird's nest"-induced anaphylaxis: An under-recognized entity?

The Chinese delicacy "bird's nest" is the most common cause of food-induced anaphylaxis requiring hospitalization among Chinese children in Singapore. This investigation has established an immunoglobulin E-mediated cause and has characterized the major putative allergens.

Adolescent↗

PubMed2000

Purification of group 2 Dermatophagoides pteronyssinus allergen and prevalence of its specific IgE in asthmatics.

Group 2 allergens are a major cause of sensitization in patients allergic to house dust mites. This study was performed to determine the prevalence of hypersensitivity to group 2 allergens (Der p 2) of Dermatophagoides pteronyssinus (Dp) in asthmatic patients in Taiwan. To facilitate the analysis of Der p 2-specific IgE, we raised a panel of monoclonal antibodies (MoAbs) to Der p 2 antigens. Purified Der p 2 was obtained after MoAb affinity column purification. There were 82 asthmatic patients (41 adults and 41 children) with hypersensitivity to Dp who were analyzed for hypersensitivity to Der p 2. All of them were both skin test- and serology test-reactive to Dp. Using purified Der p 2, 87.8% (72/82) of patients had a skin-test-positive reaction. Six adults (6/41) and 4 children (4/41) had negative skin tests for Der p 2. Ten families (both parents and children were asthmatics) of the 82 patients were selected for Der p 2 skin testing and Der p 2-specific IgE determination using immunoblot analysis. Results showed that 90% (18/20) of patients' skin reactions to Der p 2 and serum contained specific IgE to Der p 2. Because 87.8% (85.4% of adults and 90.2% of children) of the asthmatic patients with Dp hypersensitivity were allergic to Der p 2, its role in the pathogenesis of asthma in Taiwan appears to be important. Purified Der p 2 allergens can be further used for allergen skin testing and immunotherapy.

Adolescent↗

PubMed1999

Sequence polymorphism of the group 1 allergen of Bermuda grass pollen.

BACKGROUND: Cyn d 1, the major allergen of Bermuda grass pollen, consists of a number of isoforms. OBJECTIVE: To examine the extent of sequence variation of Cyn d 1 isoforms at the molecular level. METHODS: A Bermuda grass pollen lambdaZAP II cDNA expression library was immunoscreened with anti-Cyn d 1 monoclonal antibodies. The reactive clones were isolated, subcloned into Escherichia coli, and sequenced. Some of them were expressed in the yeast Pichia pastoris to obtain recombinant Cyn d 1 proteins. RESULTS: Ten cDNA clones were obtained, all these clones encode the full length of Cyn d 1 protein. Their deduced mature proteins can be grouped into: the long ones with 246 amino acids, and the short ones with 244 amino acids. The last two amino acids (AG) of the long Cyn d 1 are deleted in the short Cyn d 1. The remaining amino acid sequences share more than 98% identity; a total of nine amino acid variations were observed. Two recombinant Cyn d 1 proteins (rCyn d 3-2 and rCyn d 5-4) with three amino acid substitutions showed differential IgE-binding profiles. CONCLUSION: The present study extended our understanding of the primary structure of isoforms of Cyn d 1.

Allergens↗

PubMed1999

Allergenic differences between the domestic mites Blomia tropicalis and Dermatophagoides pteronyssinus.

BACKGROUND: House dust mite allergens are the most important indoor allergens associated with asthma and rhinitis in Singapore and the tropics. Recent data to suggest that besides the Dermatophagoides spp., the domestic mite Blomia tropicalis (Bt) is also an important source of allergens in these regions. OBJECTIVE: To evaluate the degree of allergenic cross-reactivity between Bt and D. pteronyssinus (Dp). METHODS: Cross-reactivity between extracts of Bt and Dp was evaluated by fluorescent allergosorbent (FAST) inhibition studies and cross enzyme immunoelectrophoresis. Additionally, the major Dp allergens - Der p 1, Der p 2 and Der p 5, were also compared with the Bt extract by dot blot inhibition. Skin prick and intradermal end-point titration were then carried out to compare the homologous allergens of the mite species, Blo t 5 and Der p 5. RESULTS: FAST inhibition studies showed low to moderate cross-reactivity between the two dust mite extracts (maximum cross-inhibition, 60%). Native allergens studied by cross enzyme immunoelectrophoresis using mite allergic sera also showed similar results but with at least four cross-reactive IgE binding antigens. Dot blot inhibition studies using allergens of Dp, Der p 1, Der p 2, and Der p 5, showed little cross-reactivity between these allergens with components of the crude Bt extracts. Further, evaluation of a recombinant allergen of Bt, Blo t 5, showed low levels of cross-reactivity even with its homologous Dp counterpart, Der p 5. CONCLUSION: These results provide evidence that Bt allergens are distinct and have relatively low to moderate cross-reactivity with Dermatophagoides spp. allergens. Bt allergens should therefore be included in the diagnostic panel for the evaluation of allergic disorders in the tropics, and the development of new diagnostic and therapeutic strategies should include allergens of Bt.

Allergens↗

PubMed1999

Sensitization to Blomia tropicalis and dermatophagoides pteronyssinus-a comparative study between Singapore and Taiwan.

Blomia tropicalis (Bt) and Dermatophagoides pteronyssinus (Dp) are the predominant domestic mites species in Singapore and Taiwan. This study aims to characterize and compare the mite sensitization profiles in both countries. Skin prick tests were performed on 203 Singaporeans with Dp and Bt crude extracts. In vitro IgE and IgG4 reactivity to extracts and specific allergens (Der p 1, Der p 2 Der p 5 and Blo t 5) were determined by immunoassays. Approximately 91% of the tested Singaporeans were skin test positive for both Bt and Dp. Both populations share similar frequencies of in vitro IgE reactivity to all the allergens tested, but they differ in the pattern and magnitude of allergen sensitization. Although Der p 1, Der p 2 and Blo t5 are major sensitizing allergens in both countries, Blo t 5 is a more potent one in Singapore, probably reflecting the high level of exposure to Bt. The unique major Bt and Dp allergens should be included for precise diagnosis and effective immuno-therapeutic treatment of mite allergy in both countries.

Adolescent↗

PubMed1999

Culture of Blomia tropicalis and IgE immunoblot characterization of its allergenicity.

Blomia tropicalis is an important triggering factor for allergic diseases such as asthma, rhinitis and atopic dermatitis in tropical and subtropical regions, which climate favours the growth of this species. Our previous mite fauna study revealed that Blomia tropicalis is the most dominant species present in Singapore house dust The main objective of this study is to establish a mass culture of Blomia tropicalis for further characterization of the antigenic and molecular properties of this mite. Approximately one gram of mites could be obtained for every 300-gram of culture medium by culturing under natural condition with a mean annual temperature of 30 degrees C and a mean relative humidity of 80%, and harvested by modified Tullgren funnel. Allergen characterization by IgE immunoblot analysis with crude mite extracts showed some IgE reactivity differences between Blomia tropicalis mite extract from Singapore and Colombia. The possible reasons for these findings are the quality and source of the mite protein extracts used, or selective differences in the population under evaluation. Further, the atopic sera tested showed differences in the pattern and Intensity of IgE immunoblot reactivity to crude extracts of Blomia tropicalis and Dermatophagoides pteronyssinus, the other highly prevalent mite in Singapore. These data support the existence of species-specific allergens. In conclusion, we have been successful in setting up B. tropicalis mass cultures and have prepared extracts of high allergenicity.

Allergens↗

PubMed1998

Crystallization and preliminary X-ray diffraction analysis of group 5 mite allergen from Dermatophagoides pteronyssinus.

Crystals of the 14-kDa group 5 allergen from Dermatophagoides pteronyssinus (Der p 5) have been obtained at low pH and diffract to 3-A resolution using a conventional x-ray source. The crystals belong to tetragonal space group P41212 or P43212, with unit cell parameters a = b = 114 A and c = 234 A. A self-rotation search revealed a 432 point symmetry and thus suggested 96 molecules in one unit cell, hence 12 monomers in each asymmetric unit.

Animals↗

PubMed1998

Isolation and characterization of a novel 98-kd Dermatophagoides farinae mite allergen.

BACKGROUND: Exposure to allergens from house dust mites is a significant cause of immediate hypersensitivity. Thus far, the active mite allergens defined are low molecular weight (MW) proteins or glycoproteins. However, other important mite allergens remain to be investigated. In this study a high MW mite antigen with a high IgE-binding activity was characterized. METHODS: An anti-Dermatophagoides farinae (Df) monoclonal antibody, mAb642, which recognized a 98-kd allergenic mite protein, was used for affinity chromatography. The purified Df642 was characterized biochemically and immunologically. RESULTS: Competitive ELISA demonstrated that mAb642 was inhibited by the interaction between serum IgE from allergic patients and Df642 antigen in a dose-dependent fashion. The IgE reactivity to both 98-kd and 92-kd components was removed or diminished by preincubation of asthmatic sera with Df642-coated CNBr-activated cellulose-4B gel. Two-dimensional immunoblot analysis revealed that there are at least 4 isoforms of Df642 that represent a minor component in the crude mite extract. The allergenicity of Df642 was assayed by IgE immunoassay with a large panel of 67 sera from asthmatic patients with positive skin reactions, and Df 642 showed positive IgE reactivity with more than 80% of the sera tested. Thus it should be classified as an important allergen. In addition, amino acid sequence analysis revealed that Df642 shares more than 50% homology with paramyosin from invertebrates. CONCLUSION: We have identified and characterized a 98-kd house dust mite allergen that showed greater than 80% IgE reactivity with sera from patients allergic to mites. This is the first high MW allergen characterized to date, and it shares high sequence homology with paramyosins in invertebrates.

Adolescent↗

PubMed1998

Expression of the house dust mite allergen Der p 2 in the baker's yeast Saccharomyces cerevisiae.

BACKGROUND AND RESULTS: The major house dust mite allergen Der p 2 was expressed as a recombinant mature protein in the baker's yeast Saccharomyces cerevisiae. The yeast produces the protein fused to the invertase signal peptide, leading to the secretion of Der p 2 as a soluble protein into the culture medium. The signal peptide is hereby cleaved off, resulting in a mature allergen. In this system Der p 2 was produced in 7.6 (+/-2.9) mg/L growth culture. Purification of the recombinant allergen was achieved by a single gel filtration step, resulting in a purity > or = 95%. The yeast-derived Der p 2 was almost indistinguishable from natural Der p 2 with respect to IgE-reactivity and binding to the majority of Der p 2 specific MoAbs -- as was shown in RAST analysis (n = 168) and a sandwich ELISA and RIA analysis, respectively. Recombinant and natural Der p 2 also showed similar biological activity in histamine release assays (n = 4). CONCLUSION: An expression system for Der p 2 was developed that enables the production of a soluble allergen in the culture supernatant with immunological characteristics similar to the natural allergen. In addition, yeast offers the advantage of the absence of endotoxin in comparison to E. coli. This might facilitate acceptance of recombinant allergens for in vivo applications as immunotherapy or skin-prick testing.

Allergens↗

PubMed1998

Analysis of the cross-reactivity between BtM and Der p 5, two group 5 recombinant allergens from Blomia tropicalis and Dermatophagoides pteronyssinus.

BACKGROUND: In tropical climates, sensitization to Bloma tropicalis and Dermatophagoides pteronyssinus is high and mainly directed to species-specific allergens. There is some cross-reactivity between extracts of these mites, probably due to the group 5 allergens that have high sequence homology. OBJECTIVE AND METHODS: We used the radioallergosorbent test (RAST), RAST inhibition and immunoblotting inhibition experiments to investigate the cross-reactivity between the recombinant allergens BtM and Der p 5, expressed as glutathione S-transferase fusion proteins, to detect the epitopes involved and to analyze the importance of this cross-reactivity. RESULTS: Seventy-nine percent of 48 patients sera were RAST positive to both recombinants, with a strong correlation (r = 0.8, p<0.0001). BtM inhibited 25 and 21.1% of IgE-binding to B. tropicalis and D. pteronyssinus extracts respectively and Der p 5 inhibited 22 and 24% of IgE-binding to D. pteronyssinus and B. tropicalis extracts. Furthermore, BtM inhibited 74.5% of IgE binding to Der p 5 and Der p 5 inhibited 72.4% of IgE-binding to BtM. RAST inhibition with BtM-derived synthetic peptides showed that peptide 4 (residues 35-50) and peptide 5 (residues 46-61) inhibited 37 and 16% of IgE-binding to BtM while peptides 5 and 2 (residues 14-30) were able to inhibit the IgE binding (32 and 28%, respectively) to Der p 5. CONCLUSION: There is cross-reactivity between BtM and Der p 5, which explains almost all the cross-reactivity between the two mite extracts. This cross-reactivity seems to be related to epitope(s) at the C-terminal segment of these allergens.

Allergens↗

PubMed1997

Allergen gene transfer.

DNA-based immunization induces a biased Th1 immune response, and offers a novel strategy for modulation of the Th2-associated response. Recent studies have provided evidence that antigen-induced allergic responses can be modulated in rodents immunized with plasmid DNAs encoding the sensitizing antigens. Further understanding of the regulatory mechanism involved and optimization of gene transfer/expression systems will assist greatly in proving the clinical utility of this process.

Adjuvants, Immunologic↗

PubMed1997

Biological activity of recombinant Der p 2, Der p 5 and Der p 7 allergens of the house-dust mite Dermatophagoides pteronyssinus.

Der p 2, Der p 5 and Der p 7 are three allergens of the house-dust mite Dermatophagoides pteronyssinus that have been cloned and expressed in Escherichia coli as fusion proteins with glutathione-S-transferase (GST). We showed that these recombinant allergens produced immediate hypersensitivity skin-test reactions in 70, 60 and 52% respectively of a group of mite-sensitive allergic patients who were strongly positive to whole mite extract (WME). Comparable positivities were found for serum levels of specific IgE antibody against these allergens, as measured by the radioallergosorbant test (RAST). Overall, for the group of allergic patients that we evaluated, the serum IgE antibody concentrations against Der p 2, 5 and 7 were calculated to represent about one third, one quarter and one fifth respectively of the levels measured against the WME. However, for some patients the activity determined against the separate allergens was far higher than that detected against the WME, thus indicating that the concentration of these can be limiting in the WME. We found no significant correlations between the RAST levels against Derp 2 and either Derp 5 or 7, and RAST-inhibition tests indicated a lack of cross-reactivity between Der p 2 and the other two allergens. In contrast, the RAST results revealed the existence of a significant immunological relationship between Der p 5 and 7. Although a certain degree of reactivity against the GST fusion partner was found in the allergic patients studied, this was not a significant influence in determining the positivity against the recombinant allergens. These results confirm the in vivo biological activity of recombinant Der p 2, 5 and 7, and indicate that whilst Der p 2 is undoubtedly a major mite allergen, both Der p 5 and 7 make important contributions toward the overall allergenic activity of house-dust mites.

Adult↗

PubMed1997

Sensitization to Blomia tropicalis in patients with asthma and identification of allergen Blo t 5.

In tropical and subtropical regions of the world, allergens produced by Blomia tropicalis are an important cause of IgE-mediated sensitization among patients with asthma. We compared the relative importance of sensitization to the two mite species among asthma patients from Florida, Puerto Rico, and Brazil (n = 83), who were concurrently exposed to B. tropicalis and D. pteronyssinus, with patients from the United States and from the United Kingdom (n = 56) exposed to D. pteronyssinus. In addition, molecular cloning techniques were used to clone and express a major B. tropicalis allergen. There were significant differences between IgE antibody responses to B. tropicalis and D. pteronyssinus that were related to exposure: only 22% of patients exposed to both species had a high ratio (> 10) of IgE D. pteronyssinus:B. tropicalis, whereas 68% of patients exposed only to D. pteronyssinus had a ratio of > 10 (p < 0.001). A major 14-kD allergen (Blo t 5), cloned from a B. tropicalis cDNA library, showed 43% sequence homology to D. pteronyssinus Der p 5. Recombinant Blo t 5 produced in E. coli reacted with 45 to 69% of sera from B. tropicalis-allergic asthmatics and induced positive immediate skin tests at 10(-3) to 1 microg/ml. In vivo and in vitro comparisons of IgE responses to B. tropicalis, D. pteronyssinus, rBlo t 5, and rDer p 5, showed that B. tropicalis has unique allergens that cause specific IgE responses. The results suggest that B. tropicalis is an independent cause of sensitization and that use of recombinant Blo t 5 should lead to a better understanding of the role of B. tropicalis in causing asthma in tropical environments.

Adolescent↗

PubMed1997

Characterization of the allergen Der f 7 from house dust mite extracts by species-specific and crossreactive monoclonal antibodies.

BACKGROUND: The group 7 mite allergens react with IgE in 50% of sera from allergic patients. OBJECTIVE: To determine the molecular and antigenic characteristics and heterogeneity of Der f 7 in mite extracts. METHODS: Monoclonal antibodies (MoAbs) produced from mice immunized with recombinant Der f 7 were examined for crossreactivity to Der p 7 and then used for immunoblotting of 1 and 2-D gel electrophoresis. Deglycosylation was studied with N-glycosidase-F and N-terminal sequencing by Edman degradation. The epitopes of the monoclonal antibodies were compared by cross-inhibitory immunoassays. RESULTS: Immunoblotting of D. farinae extracts with all the anti Der f 7 MoAbs showed major reactivities at 31, 30 and 25 kDa. The strongest immunostaining was at 25 kDa which contrasted with Der p 7 where the 31 and 30 kDa bands were strongest. The relative strength of staining however varied between extracts. The 31 and 30 kDa components were glycosylation products of the 25 kDa form which had the N-terminal sequence predicted from cDNA analysis. Two MoAbs stained an 18 kDa band consistent with a degradation product. The 2-D gels showed that different components with pIs from 5.6-6.4. Both species-specific and Der p 7 crossreactive MoAbs were produced and a two-site ELISA assay for detecting group 7 allergen was developed with MoAbs recognizing different epitopes. CONCLUSIONS: Der f 7 has been defined by its natural N-terminal sequence and MoAbs. It apparently exists as different glycosylation and degradation products in mite extracts, the relative abundance of which differs with different preparations. A two-site ELISA to measure the allergen was developed.

Allergens↗