Cockroach cause of allergic asthma *1, *2Its specificity and immunologic profile

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An allergen cloned from a Blattella germanica (German cockroach) cDNA library, encoded a 182-amino acid protein of 20,904 Da. This protein, designated B. germanica allergen 4 (Bla g 4), was expressed as a glutathione S-transferase fusion protein in Escherichia coli and purified by affinity chromatography and high-performance liquid chromatography. The prevalence of serum IgE antibody to recombinant Bla g 4 in 73 cockroach allergic patients with asthma ranged from 40% (antigen binding radioimmunoassay) to 60% (plaque immunoassay). Cockroach allergic patients gave positive intradermal skin tests to recombinant Bla g 4 at concentrations of 10 ؊3 -10 ؊5 g/ml, whereas non-allergic controls, or cockroach allergic patients with no detectable serum IgE antibody to Bla g 4, gave negative skin tests to 1 g/ml. Polymerase chain reaction and Southern analysis identified a 523-base pair DNA encoding Bla g 4 in both B. germanica and Periplaneta americana (American cockroach). However, Northern analysis showed that mRNA encoding Bla g 4 was transcribed in B. germanica but not in P. americana, suggesting that allergen expression was species specific. Sequence similarity searches showed that Bla g 4 was a ligand binding protein or calycin and unexpectedly revealed that this family contained several important allergens: ␤-lactoglobulin, from cow milk, and rat and mouse urinary proteins. Although the overall sequence homology between these proteins was low (ϳ20%), macromolecular modeling techniques were used to generate two models of the tertiary structure of Bla g 4, based on comparisons with the x-ray crystal coordinates of bilin binding protein and rodent urinary proteins. The results show that members of the calycin protein family can cause IgE antibody responses by inhalation or ingestion and are associated with asthma and food hypersensitivity.

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confidence: 99%

Cloning of Cockroach Allergen, Bla g 4, Identifies Ligand Binding Proteins (or Calycins) as a Cause of IgE Antibody Responses

Arruda

Vailes

Hayden

et al. 1995

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118

“…Cockroaches, commonly found in urban dwellings worldwide, have long been considered vectors of various infectious diseases and recognized as one of the major causes of inhalant allergy and asthma (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Cockroaches represent a health problem to allergic subjects living in cockroach-infested environments.…”

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confidence: 99%

Sequencing Analysis of cDNA Clones Encoding the American Cockroach Cr-PI Allergens

Lee

Liao

et al. 1996

A previous article described the isolation of several gt22A cDNA clones expressing the American cockroach (Periplaneta americana) Cr-PI allergens recognized by both human atopic IgE antibodies and anti-Cr-PI monoclonal antibodies (Wu, C. H., Lee, M. F., and Liao, S. C. (1995) J. Allergy Clin. Immunol. 96, 352-359). This article presents the nucleotide and deduced amino acid sequences of two cDNA clones encoding major allergens of P. americana. Clones C12 and C20 encode proteins of 685 and 631 amino acids with two potential N-glycosylation sites each. The predicted molecular weights for C12 and C20 cloned proteins are 79,300 and 75,500 with isoelectric point values of 6.26 and 6.63, which are compatible with the determined sizes (M r 78,000 and 72,000) and isoelectric point value (6.2) of the Cr-PI allergens of P. americana. A high degree of identity (69.1%), including several overlapped predicted central antigenic determinant residues, was found between two allergens. The anti-fusion protein antibody-based enzyme-linked immunosorbent assay was able to detect crude American cockroach extract, Cr-PI, recombinant proteins, and commercial cockroach extracts, which provides further evidence that two allergens share common antigen determinants. Recombinant allergens of clones C12 and C20 both showed 47.4% skin reactivities on 19 cockroach-sensitive asthmatic patients. Unexpectedly, although no sequence similarity was found to other known allergens, two aromatic amino acid-rich allergens were found to have a striking sequence identity to insect storage proteins (20.1-33.9%), insect juvenile hormone-suppressible proteins (30.9 -36.4%), and arthropod hemocyanins (29.7-34.6%). Results suggested that two prominent allergens of P. americana are ancestrally related to these insect hemolymph proteins and represent a new group of proteins in the hemocyanin superfamily. These data will now facilitate epitope-mapping studies, and the recombinant allergens may be valuable for diagnostic and therapeutic purposes.

“…Cockroaches produce potent allergens, which give rise to IgE antibody (Ab) 1 responses in genetically predisposed individuals living in cockroach-infested housing (1)(2)(3)(4)(5)(6)(7)(8). IgE Ab to cockroach are strongly associated with asthma, and sensitization to cockroach allergens is a major risk factor for hospital emergency room visits for asthma (5,9,10).…”

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confidence: 99%

Induction of IgE Antibody Responses by GlutathioneS-Transferase from the German Cockroach (Blattella germanica)

Arruda¹,

Vailes²,

Platts-Mills³

et al. 1997

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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 NH 2 -terminal sequence of the natural protein and the deduced amino acid sequence from cDNA were identical except for one substitution (Phe 9 3 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 xray 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.Cockroaches produce potent allergens, which give rise to IgE antibody (Ab) 1 responses in genetically predisposed individuals living in cockroach-infested housing (1-8). IgE Ab to cockroach are strongly associated with asthma, and sensitization to cockroach allergens is a major risk factor for hospital emergency room visits for asthma (5,9,10). Although cockroach may carry viral and bacterial pathogens, asthma is the only disease for which an unequivocal causal relationship with cockroach exposure has been established (9 -11). Over the last few years, several allergens from the principal domiciliary cockroach species, Blattella germanica (German cockroach) and Periplaneta americana (American cockroach), have been cloned and insights into their biological function have been obtained (12-15). B. germanica allergen Bla g 2 shows sequence homology to aspartic proteases, whereas Bla g 4 is a ligand-binding protein or calycin (12, 13). In Taiwan, P. americana is an important cause of asthma, and a 72-kDa allergen, Per a 3, has recently been cloned, which shows homology to insect hemolymph proteins (arylphorins) (14).We have identified an important B. germanica allergen with sequence homology to the glutathione S-transferase (GST) superfamily. These enzymes are involved in the detoxification of endogenous and xenobiotic toxic compounds and are widely distributed in most forms of life (16 -18). In molecular biology, plasmid vectors have been constructed to express foreign proteins in Escherichia coli, as fusion proteins with the COOH terminus of GST from Schistosoma japonicum. These high level expression systems (pGEX vectors) have been widely used for purification of recombinant proteins by glutathione affinity chromatography (19).Here, we report the sequence, purification, and recombinant expression...