PubMed Health⌕ Search

Biomedical subjects

L K Arruda

Publications and source records attributed to L K Arruda.

At least 19 recordsLinked to original sources
PubMed2003

Skin test reactivity to natural and recombinant Blomia and Dermatophagoides spp. allergens among mite allergic patients in the UK.

BACKGROUND: Many asthmatics in tropical and subtropical areas have positive skin prick tests to both Dermatophagoides spp. and to the mite Blomia tropicalis. This may be due to recognition by IgE of cross-reactive allergens between the different mite species or because of sensitization to species-specific allergens. A 14-kDa Blomia tropicalis allergen, Blo t 5, has been cloned and shows 40% sequence homology with Der p 5. The aim of this study was to investigate reactivity to B. tropicalis in patients known to be sensitized to D. pteronyssinus and to assess allergenic activity and cross-reactivity of recombinant (r) Group 5 allergens amongst these patients, who live in the UK and who are not exposed to B. tropicalis in their homes. METHODS: Patients (n = 19) with asthma and/or rhinitis were selected based on clinical history and a positive skin prick test to D. pteronyssinus extract and were compared with non-allergic skin test negative controls (n = 10). IgE antibody responses to Blomia tropicalis, Dermatophagoides pteronyssinus, rDer p 5 and rBlo t 5 were compared by quantitative intradermal skin testing using serial 10-fold dilutions of each allergen. End point titre was the highest dilution giving an 8 x 8 mm wheal at 15 min. IgE antibodies to Blomia tropicalis, Dermatophagoides pteronyssinus, rDer p 5 and rBlo t 5 were measured using RAST, CAP and RIA, respectively. RESULTS: All 19 patients had positive skin tests to D. pteronyssinus at concentrations of 0.001 to 1 AU/ml and 10 were skin test positive to rDer p 5 at concentrations of 10-4 to 5 micro g/ml. Positive intradermal tests to Blomia tropicalis were seen in 12/19 patients at concentrations of 0.002 to 2 micro g/ml. However none of the patients had positive skin tests to rBlo t 5. Non-allergic controls were all skin test negative at the highest concentration of each allergen tested. All subjects had quantifiable specific IgE to D. pteronyssinus, but only two had IgE to B. tropicalis. IgE to Der p 5 was found in six patients, but no patients had IgE to Blo t 5. CONCLUSIONS: This study of patients naturally exposed to D. pteronyssinus but not to Blomia tropicalis, provides evidence for IgE mediated cross-reactivity between allergens produced by both mite species. The results suggest that the Group 5 allergens of D. pteronyssinus and B. tropicalis are species-specific.

Adult↗
PubMed2002

Use of a chimeric ELISA to investigate immunoglobulin E antibody responses to Der p 1 and Der p 2 in mite-allergic patients with asthma, wheezing and/or rhinitis.

BACKGROUND: Sensitization to indoor allergens, particularly to dust mites, is a strong risk factor for asthma in children and adults. Assessment of sensitization is carried out using in vivo and in vitro tests to detect specific IgE antibodies. OBJECTIVE: To investigate IgE antibody responses to mites in patients with asthma, wheezing and/or rhinitis, using chimeric ELISA to measure specific IgE antibodies to mite allergens Der p 1 and Der p 2. METHODS: Specific IgE antibodies to Der p 1 and Der p 2 were quantified by chimeric ELISA, and compared with IgE to Dermatophagoides pteronyssinus (Dpt) measured using the CAP system (Pharmacia). A panel of sera from 212 patients with asthma, wheezing and/or rhinitis and 11 controls was analysed. RESULTS: There was a significant correlation between IgE to Dpt measured by CAP and IgE to Der p 1 (r = 0.81, P < 0.001), Der p 2 (r = 0.79, P < 0.001) and combined Der p 1 and Der p 2 (r = 0.86, P < 0.001). Seventy per cent of all patients had IgE to Dpt, and of those, 76.5% had IgE to Der p 1, 79.2% had IgE to Der p 2 and 83.1% had IgE to Der p 1 and Der p 2 combined. Considering the cut-off level of 2 IU/mL of IgE to either Der p 1 or Der p 2, the predictive value for a positive IgE to Dpt by CAP was greater than 95%. CONCLUSIONS: The chimeric ELISA allowed accurate quantification of IgE antibodies to Dpt allergens Der p 1 and Der p 2, and it could be useful for studying immune responses to mites in patients with asthma and/or rhinitis.

Adolescent↗
PubMed2001

Cockroach allergens: environmental distribution and relationship to disease.

Cockroach allergy has been recognized as an important cause of asthma. Exposure to high levels of cockroach allergens in the home is a major risk factor for symptoms in sensitized individuals. Previously identified allergens from Blatella germanica and Periplaneta americana include Bla g 2 (inactive aspartic proteinase), Bla g 4 (calycin), Bla g 5 (glutathione-S-transferase), Bla g 6 (troponin), the Group 1 cross-reactive allergens Bla g 1 and Per a 1, Per a 3 (arylphorin), and Per a 7 (tropomyosin). The primary site of cockroach allergen accumulation is the kitchen. However, lower levels of allergen can be found in bedding, on the bedroom floor, and in sofa dust. Strategies for decreasing exposure to cockroach have been investigated. The results suggest that a sustained decrease in cockroach allergen levels is difficult to accomplish, even after successful extermination of cockroach populations. The use of recombinant cockroach allergens may lead to the development of new approaches to asthma treatment in the future.

Air Pollutants↗
PubMed2001

A sensitive reverse ELISA for the measurement of specific IgE to Der p 2, a major Dermatophagoides pteronyssinus allergen.

BACKGROUND: Epidemiologic studies have shown that the presence of IgE antibodies to house dust mite and other indoor allergens is an important risk factor for asthma. OBJECTIVE: The aim of this study was to develop a reverse ELISA (rELISA) for measuring specific IgE to Der p 2, a major Dermatophagoides pteronyssinus (Dpt) allergen, as a potential tool for followup of allergen immunotherapy. METHODS: Recombinant Der p 2 allergen or a monoclonal antibody to Der p 2 was used to coat plates in conventional ELISA (cELISA) and rELISA, respectively. Sera from 48 asthmatic patients with positive skin prick test (SPT+) to D. pteronyssinus extract were analyzed for total IgE and specific IgE to Der p 2, and the results were compared with a group of 41 SPT asthmatic and 30 SPT- control subjects. RESULTS: The sensitivity of the two assays for Der p 2-specific IgE was 3.9 EU/mL and their specificities were confirmed by inhibition tests, in a dose-dependent manner. There was a significant positive correlation between cELISA and rELISA (r = 0.74; P < 0.0001). However, rELISA was more sensitive than was cELISA, regarding both the positive sera percentage (70.8% vs 52.1%) and the Der p 2-specific IgE levels (28.4 vs 4.5 EU/mL) in SPT+ asthmatic patients. CONCLUSIONS: rELISA has shown to be a sensitive and alternative method for measuring Der p 2-specific IgE without using radioactive techniques. Detection of specific IgE to major allergens and relevant peptides, and identification of B cell epitopes in allergens will provide valuable information for the design of allergen analogs and peptides for immunotherapy.

Adolescent↗
PubMed2001

International Study of Asthma and Allergies in Childhood: validation of the rhinitis symptom questionnaire and prevalence of rhinitis in schoolchildren in São Paulo, Brazil.

Written questionnaires (WQ) have been widely used in epidemiologic studies. In order to yield comparable results, they must be validated after translation to another language. The International Study of Asthma and Allergies in Childhood (ISAAC) WQ has been previously validated by a comprehensive study, but its validation in Brazil has not been performed. Our objectives were to validate the rhinitis component of the ISAAC's self-applicable WQ following its translation to Portuguese, and to determine the prevalence of rhinitis and related symptoms among Brazilian children living in the city of São Paulo. A group of 10 pediatricians and 10 pediatric allergists graded the questions from 0 to 2 and established a maximum score for each question. The WQ was answered by parents or guardians of children 6-7 years of age with rhinitis (R) (n = 27) and of control children of the same age without rhinitis (C) (n = 27). The WQ was also completed by adolescents 13-14 years of age with rhinitis (R) (n = 32) and without rhinitis (C) (n = 32). Half of these individuals answered the same WQ after 2-4 weeks, to ensure reproducibility. Cut-off scores of 4 and 3 were identified for the 6-7- and 13-14-year-old groups, respectively, as scores predictive of rhinitis. The prevalence of rhinitis was 28.8% in the group of 3005 children 6-7 years of age and 31.7% in the group of 3008 children 13-14 years of age, respectively. Using the global cut-off score, these prevalences were even higher, in the order of 34.7% and 40.7%, respectively. In conclusion, the rhinitis component of the ISAAC WQ was proven to be reproducible, adequate and able to discriminate children and adolescents with and without rhinitis, and revealed that the prevalence of rhinitis among Brazilian children living in the city of São Paulo was as high as the prevalence of rhinitis in other areas of the world.

Adolescent↗
PubMed2001

Cockroach allergens and asthma.

Asthma and allergy are the most common diseases associated with cockroach infestation of houses in the United States and other parts of the world. Sensitization and exposure to cockroach allergens is associated with increased asthma morbidity in the United States, especially among lower socioeconomic groups, including African American and Hispanic populations. Exposure to cockroach allergens in the first 3 months of life has been associated with repeated wheezing and asthma. The principal domestic cockroach species are Blattella germanica and Periplaneta americana. Both species produce several potent allergens, including Bla g 2 (inactive aspartic proteinase), Bla g 4 (calycin), Bla g 5 (glutathione-S-transferase), the group 1 cross-reactive allergens Bla g 1 and Per a 1, and tropomyosin. Structural homology between tropomyosins from cockroaches, mites, and shrimp may explain clinical cases of the oral allergy syndrome. The 3-dimensional structures of several cockroach allergens are known, and biologically active recombinant allergens have been produced in high-level expression vectors. The use of recombinant cockroach allergens should allow mechanisms of cockroach-induced asthma to be investigated and may lead to the development of new approaches to asthma treatment. Environmental allergen measurements of Bla g 1 and Bla g 2 have allowed exposure levels that cause allergic sensitization to be established. Abatement studies have shown that a sustained decrease in cockroach allergen levels is difficult but can be accomplished by professional application of insecticides, together with rigorous household cleaning. Cockroach asthma is an important public health problem that affects patients who are the least likely to be compliant with treatment with asthma medications or environmental control. Patient education, improvements in the housing stock, and improvements in environmental and immunologic treatment strategies are likely to be the most successful approaches to reduce the prevalence of cockroach-induced asthma.

Allergens↗
PubMed2001

Ecology and elimination of cockroaches and allergens in the home.

Cockroach infestations have been indicated as a major contributor to asthma throughout the world. Several studies have shown that large numbers of asthmatic patients are sensitized to cockroach allergens. Eliminating this pest from homes, schools, and public buildings involves a long-term commitment to a rational extermination process. This article covers the characteristics of the major cockroach species that invade homes, assesses the role of environmental exposure to cockroaches in asthma, and provides an intervention program for their extermination.

Air Pollution, Indoor↗
PubMed2001

The role of cockroach allergens in asthma.

Cockroach allergy has been recognized as an important cause of asthma. Cockroach asthma has been described as a more severe disease, associated with perennial symptoms and high levels of total IgE. Cockroaches produce several allergens that induce sensitization, and exposure to high levels of cockroach allergens in the home is a major risk factor for symptoms in sensitized individuals. Previously identified allergens from Blattella germanica and Periplaneta americana, the most important domiciliary species, include Bla g 2 (inactive aspartic protease), Bla g 4 (calycin), Bla g 5 (glutathione-S-transferase), Bla g 6 (troponin), the Group 1 cross-reactive allergens Bla g 1 and Per a 1, Per a 3 (arylphorin), and Per a 7 (tropomyosin). Strategies for decreasing environmental exposure to cockroach have been recently investigated. The results suggest that a sustained decrease in cockroach allergen levels is difficult to accomplish, even after successful extermination of cockroach populations. Cockroach allergens have been cloned and produced as recombinant proteins in high-level expression vectors. The use of recombinant cockroach allergens should allow mechanisms of cockroach-induced asthma to be investigated and may lead to the development of new approaches to asthma treatment in the future.

Allergens↗
PubMed2001

Allergic and immunologic parameters in patients with Fanconi's anemia.

BACKGROUND: Fanconi's anemia (FA) is a rare recessive chromosomal instability disorder, characterized by progressive bone marrow failure and congenital defects. Patients with FA present with recurrent infections, particularly those of the respiratory tract. OBJECTIVE: The aim of the present study was to evaluate whether patients with FA have altered antibody-mediated immune responses. METHODS: A group of 12 patients with FA, 5-32 years old (6 males) was studied. Serum levels of IgG, IgM, IgA and IgG subclasses, isohemagglutinin titers and specific IgG antibodies to poliovirus and measles were determined using standard methods. Immediate skin tests to common inhalant allergens were performed, and total and specific serum IgE was quantitated using a fluoroenzymatic assay (Uni-CAP, Pharmacia). Antipneumococcal antibodies were measured by ELISA before and 4-8 weeks after immunization with pneumococcal vaccine (Pneumo 23, Pasteur Mérieux Connaught). Responses to serotypes 1, 3, 5, 6B, 9V and 14, which are the most prevalent in our country, were studied. RESULTS: Ten patients had elevated IgE levels in sera, and 7 of them had detectable specific IgE and positive immediate skin tests. An inadequate response to pneumococcal vaccination was found in 2 of the 12 patients. Isohemagglutinin titers and levels of IgG, IgM, IgA and IgG subclasses and antipoliovirus and antimeasles antibodies were within the normal limits for age in all patients. Two patients had undetectable IgG4 levels (below 5 mg/dl). CONCLUSIONS: The results indicate that a proportion of patients with FA (2/12) in our study had inadequate responses to pneumococcal vaccination. No other significant abnormalities of the immune system were found in these patients.

Adolescent↗
PubMed2000

Recombinant allergens for diagnosis and therapy of allergic disease.

Many of the problems associated with using natural allergenic products for allergy diagnosis and treatment can be overcome with use of genetically engineered recombinant allergens. Over the past 10 years, the most important allergens from mites, pollens, animal dander, insects, and foods have been cloned, sequenced, and expressed. In many cases the three-dimensional allergen structure has been determined and B-cell and T-cell epitopes have been mapped. These studies show that allergens have diverse biologic functions (they may be enzymes, enzyme inhibitors, lipocalins, or structural proteins) and that as a rule the allergen function is unrelated to its ability to cause IgE antibody responses. High-level expression systems have been developed to produce recombinant allergens in bacteria, yeast, or insect cells. Recombinant allergens show comparable IgE antibody binding to their natural counterparts (where available) and show excellent reactivity on skin testing and in in vitro diagnostic tests. Cocktails of recombinant allergens can be formulated with predetermined and uniform allergen levels, which could replace natural allergens and result in the development of innovative, patient-based tests for allergy diagnosis. Recombinant allergens also offer the exciting possibility of developing new forms of allergen immunotherapy, including the use of hypoallergens, allergens coupled to IgE suppressive adjuvants, and peptide-based therapies. The production of recombinant allergens as defined molecular entities makes it feasible to consider the possibility of developing prophylactic allergen vaccines. The introduction of recombinant allergens in research and in clinical trials should lead to significant improvements in allergy diagnosis and treatment.

Allergens↗
PubMed2000

Dermatophagoides farinae (Der f 1) and Dermatophagoides pteronyssinus (Der p 1) allergen exposure among subjects living in Uberlândia, Brazil.

BACKGROUND: The role of mite allergen exposure in sensitization and development of asthma has been widely recognized. Previous studies have shown that Dermatophagoides pteronyssinus and Blomia tropicalis were the most prevalent house dust mites in Brazil, while D. farinae was rarely found. The aim of this study was to measure Der f 1 and Der p 1 allergen levels in Brazilian asthmatics' and controls' homes. METHODS: Sixty-four houses (32 asthmatic, 32 control) were visited for dust sampling from five sites. Der f 1 and Der p 1 levels were measured by two-site monoclonal-antibody-based ELISAs. RESULTS: The highest levels of Der f 1 and Der p 1 allergens were found in bedding samples from both asthmatics' and controls' homes. However, the geometric mean of Der f 1 levels (15.8 microgram/g of dust) was significantly higher than for Der p 1 (8.2 microgram/g of dust) in these samples. In addition, allergen levels >/=10 microgram/g of dust were found in 60-80% of the samples for Der f 1 and about 50% for Der p 1. CONCLUSIONS: These results indicate that high levels of Der f 1 allergen are present in both asthmatics' and controls' homes, in contrast to previously reported data. Therefore, studies on exposure to mites should be performed in different cities, seasons and times, since the mite fauna might be subject to variations. Knowledge of the mite fauna will certainly improve the means of investigating the association between allergen exposure and sensitization, allowing to establish the inclusion of new mite extracts in inhalant skin test sets, and even to detect monosensitized patients with respiratory allergy.

Adolescent↗
PubMed1999

Cockroach allergens and asthma in Brazil: identification of tropomyosin as a major allergen with potential cross-reactivity with mite and shrimp allergens.

BACKGROUND: Cockroaches produce several proteins that induce IgE antibody responses. Although cockroaches are abundant in warm and humid areas, sensitization to cockroach allergens has not been investigated in Brazil. OBJECTIVE: The aims of this study were to investigate the frequency of cockroach allergy among patients with asthma, rhinitis, or both in Brazil and to identify American cockroach allergens. METHODS: Skin tests using cockroach extracts were performed on children and young adults with asthma, rhinitis, or both. A Periplaneta americana complementary (c)DNA library was screened by using IgE antibodies from Brazilian patients allergic to cockroaches. Reactivity of an mAb directed to Dermatophagoides pteronyssinus tropomyosin against cockroach tissue was examined by immunofluorescence. RESULTS: Cockroach allergy was present in 55% and 79% of the patients, as determined by using skin prick tests alone or combined prick and intradermal tests, respectively. Five cDNA clones reacted with IgE antibody and contained the same sequence. A representative clone (1300 bp), pa 12, coded for a protein that reacted with 50% of the sera from patients allergic to cockroaches on plaque immunoassay and showed a high degree of homology to tropomyosins, particularly those from invertebrates. P americana tropomyosin showed 80%, 81%, and 82% sequence identity to tropomyosins from D pteronyssinus, D farinae, and shrimp, respectively, which have been previously defined as important allergens. An mAb directed against D pteronyssinus tropomyosin, which also recognizes shrimp tropomyosin, showed binding to cockroach striated muscle. CONCLUSION: Our results support the recommendation that cockroach extracts should be routinely used for the evaluation of patients with asthma, rhinitis, or both in Brazil. The identification of P americana tropomyosin as an important allergen will make it possible to investigate cross-reactivity among cockroaches, mites, and food derived from invertebrates.

Adolescent↗
PubMed1999

Molecular cloning of Per a 1 and definition of the cross-reactive Group 1 cockroach allergens.

BACKGROUND: Sensitization to allergens produced by German and American cockroaches is strongly associated with the cause of asthma. Most of the cockroach allergens identified to date have been species specific. OBJECTIVE: The aim of this study was to identify and sequence cross-reactive cockroach allergens. METHODS: A Periplaneta americana cDNA library was screened with IgE antibody from patients in the United States who were allergic to cockroach and who were sensitized to Blattella germanica. RESULTS: A cDNA clone was isolated that contained an 870-bp sequence with a 695-bp open reading frame, encoding a 231 amino acid protein, molecular weight 26.2 kd. Plaque immunoassays using anti-Bla g 1 and anti-Per a 1 mAbs and a panel of human IgE antibodies showed that the protein expressed by these clones was Per a 1. Sequence homology searches showed that Per a 1 was homologous to 5 previously reported, but unidentified, sequences from B germanica and P americana. These sequences encoded proteins with multiple molecular sizes containing approximately 100 amino acid repeats. The Per a 1 sequence also showed 31% identity to a mosquito precursor protein, ANG12, which may be involved in digestion. The Per a 1 cDNA was expressed in Pichia pastoris to produce purified recombinant allergen (yield, 14 mg/L). CONCLUSION: The results define the molecular structure and antigenic relationships between a new family of cross-reactive "Group 1" allergens produced by both P americana and B germanica. These recombinant allergens and specific mAbs will provide tools to improve the diagnosis and treatment of allergic diseases caused by cockroaches.

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↗
PubMed1998

Novel allergen structures with tandem amino acid repeats derived from German and American cockroach.

Cockroaches produce potent allergens that are an important cause of asthma. The two principal domiciliary cockroach species, Blattella germanica and Periplaneta americana, secrete major allergens, Bla g 1 and Per a 1. Here, we report the molecular cloning of three Bla g 1 cDNA clones, which showed 70% amino acid sequence identity with Per a 1. Plaque immunoassays with human IgE antibodies or murine monoclonal antibodies showed that these allergens were antigenically cross-reactive. The Bla g 1 sequences also showed homology to five previously undefined cockroach allergen sequences. An unusual feature of all these sequences was that they contained multiple tandem amino acid repeats of approximately 100 amino acid residues. Between one and seven repeat units were identified by dot-plot matrix analysis. The sequences also showed homology to a mosquito protein involved in digestion (ANG12 precursor) and to mitochondrial energy transfer proteins. High levels of Bla g 1 were found in cockroach hindgut and proventriculus. Amino acid sequencing of natural Bla g 1 and Per a 1 suggested that these allergens are cleaved by trypsin-like enzymes following secretion into the digestive tract. The repeat sequences appear to have evolved by duplication of an ancestral amino acid domain, which may have arisen from the mitochondrial energy transfer proteins.

Allergens↗
PubMed1998

High-level expression of cockroach allergen, Bla g 4, in Pichia pastoris.

Exposure to cockroach allergens is a risk factor for allergic disease and has been linked to an increase in asthma morbidity among cockroach-sensitive inner-city children. Bla g 4 is a ligand-binding protein (or calycin) that causes IgE antibody responses in 40% to 60% of patients allergic to cockroaches. Recombinant Bla g 4 was expressed in Escherichia coli as an 18 kd protein but provided poor yields (only 0.25 mg/L culture). To improve yields, Bla g 4 was expressed in the Pichia pastoris yeast system as a 23 kd secreted protein at concentrations of 50 mg allergen/L. By cross-inhibition radioimmunoassay, Bla g 4 expressed in E. coli or P. pastoris provided overlapping inhibition curves. Both allergen preparations bound comparable levels of serum IgE antibody and showed similar skin test reactivity in individuals allergic to cockroaches (10[-1] to 10[-3] microg/ml). Deglycosylation of Pichia-expressed Bla g 4 with endoglycosidase F resulted in an 18 to 20 kd doublet, and liquid chromatography-mass spectrometry results suggested that the 20 kd band contained residual sugar residues. Both glycosylated and deglycosylated Pichia Bla g 4 showed comparable inhibition of IgE antibody binding in radioimmunoassay. Pichia-produced Bla g 4 had the same antigenic reactivity as that produced in E. coli, and glycosylation had no effect on IgE antibody binding. The high yield of Bla g 4 obtained in the Pichia system will facilitate studies on the structure and function of calycin allergens and on the immune response of asthma patients to cockroach allergens.

Allergens↗
PubMed1997

Induction of IgE antibody responses by glutathione S-transferase from the German cockroach (Blattella germanica).

We report that a major 23-kDa allergen from German cockroach (Blattella germanica) is a glutathione S-transferase (EC 2.5.1.18; GST). Natural B. germanica GST, purified from cockroach body extracts by glutathione affinity chromatography, and recombinant protein expressed in Escherichia coli using the pET21a vector, showed excellent IgE antibody binding activity. B. germanica GST caused positive immediate skin tests in cockroach-allergic patients using as little as 3 pg of recombinant protein. The NH2-terminal sequence of the natural protein and the deduced amino acid sequence from cDNA were identical except for one substitution (Phe9 --> Cys). Assignment of this protein to the GST superfamily was based on binding to glutathione and sequence identity (42-51%) to the GST-2 subfamily from insects, including Anopheles gambiae and Drosophila melanogaster. B. germanica GST contained 18 of the 26 invariable residues identified in mammalian GST by x-ray crystallography and exhibited enzymic activity against a GST substrate. Our results show that cockroach GST causes IgE antibody responses and is associated with asthma. The data strongly support the view that the immune response to GST plays an important role in allergic diseases.

Allergens↗