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Purpose: Allergens present in the feces or frass of cockroaches can cause allergic sensitization in humans. The use of fecal and frass extracts for immunotherapy has been previously investigated but has not yet been fully standardized. Here, we treated cockroaches with ampicillin to produce extracts with reduced amounts of total bacteria., Methods: We performed targeted high-throughput sequencing of 16S rDNA to compare the microbiomes of ampicillin-treated and untreated (control) cockroaches. RNA-seq was performed to identify differentially expressed genes (DEGs) in ampicillin-treated cockroaches., Results: Analysis of the microbiome revealed that alpha diversity was lower in the ampicillin-treated group than in the control group. Beta diversity analysis indicated that ampicillin treatment altered bacterial composition in the microbiome of cockroaches. Quantitative polymerase chain reaction revealed that almost all bacteria were removed from ampicillin-treated cockroaches. RNA-seq analysis revealed 1,236 DEGs in ampicillin-treated cockroaches (compared to untreated cockroaches). Unlike bacterial composition, the DEGs varied between the two groups. Among major allergens, the expression of Bla g 2 decreased significantly in ampicillin-treated cockroaches (compared to untreated group)., Conclusions: In this study, the reduced level of allergens observed in cockroaches may be related to lower amounts of total bacteria caused by treatment with antibiotics. It is possible to make a protein extract with few bacteria for use in immunotherapy., Competing Interests: The authors have declared that no competing interests exist.

Parasite infections modulate immunologic responses, and the loss of parasite infections in the last two to three decades might explain the increased prevalence of allergic diseases in developed countries. However, parasites can enhance allergic responses. Parasites contain or release allergen-like molecules that induce the specific immunoglobulin, IgE, and trigger type-2 immune responses. Some parasites and their proteins, such as Anisakis and Echinococcus granulosus allergens, act as typical allergens. A number of IgE-binding proteins of various helminthic parasites are cross-reactive to other environmental allergens, which cause allergic symptoms or hamper accurate diagnosis of allergic diseases. The cross-reactivity is based on the fact that parasite proteins are structurally homologous to common environmental allergens. In addition, IgE-binding proteins of parasites might be useful for developing vaccines to prevent host re-infection. This review discusses the functions of the IgE-biding proteins of parasites., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Although basophils and mast cells share similar phenotypic and functional properties, little is known about the difference in the initial Th2 immune responses of these cells following exposure to proteolytic allergens. Here, we investigated the mechanisms of Th2-mediated immune responses in mouse bone marrow-derived basophils (BMBs) and mast cells (BMMCs) via stimulation with the cysteine protease allergen Der f 1. Our results showed that Th2 cytokines were induced from BMBs by active recombinant Der f 1 (rDer f 1 independently with Toll-like receptor (TLR) 2 and TLR4. Although both BMBs and BMMCs expressed protease-activated receptors on their surfaces, PAR expression following exposure to rDer f 1 was altered only in basophils. G protein-coupled receptors in basophils were found to be associated with interleukin (IL)-4 and IL-13 production from BMBs upon Der f 1 treatment. Secretion of Th2 cytokines from rDer f 1-treated basophils was mediated by G protein βγ and phosphatidylinositol 3-kinase γ through the extracellular signal-regulated kinase and c-Jun N-terminal kinase pathways. These findings provide insights into the roles of cysteine proteases in Th2 immune responses, such as allergic diseases, and improve our understanding of the mechanisms of Th2 cytokine production.

Background: Stings from the Asian needle ant are an important cause of anaphylaxis in East Asia. A 23-kDa protein homologous to antigen 5 is the major allergen produced by these ants. In this study, we aimed to produce a recombinant antigen 5 allergen, Pac c 3., Methods: Recombinant Pac c 3 allergen from the Asian needle ant was expressed in Pichia pastoris and purified by ammonium sulfate precipitation and Ni affinity chromatography. IgE reactivity was demonstrated by ELISA and immunoblotting., Results: The recombinant protein was recognized in 5 of 6 (83.3%) serum samples from patients with demonstrated anaphylaxis to ants. IgE reactivity to an antigen 5 allergen from Asian needle ant venom sac extract was specifically inhibited by the recombinant protein. It was also able to inhibit IgE binding to the vespid allergen Ves v 5 by ImmunoCAP analysis, indicating the presence of cross-reactivity., Conclusion: A recombinant Pac c 3, cross-reactive with Ves v 5, from the Asian needle ant was successfully produced in the methylotrophic yeast P. pastoris. This protein could be useful for the development of component-resolved diagnostics., (© 2016 S. Karger AG, Basel.)

Group-5 and group-21 allergens, produced by house dust mites and storage mites are 36.6-55.8% identical in their sequences and are recognized by at least 50% of immunoglobulin (Ig)E from the sera of individuals allergic to dust mites. In the present study, recombinant group-5 and ‑21 allergens from three mite species, Dermatophagoides farinae (rDer f 5 and 21), Tyrophagus putrescentiae (rTyr p 5 and 21), and Blomia tropicalis (rBlo t 5 and 21), were purified from Escherichia coli, and the IgE reactivities and cross‑reactivities of these allergen variants were assessed. The IgE binding frequencies of rDer f 5, rDer f 21, rTyr p 5, rTyr p 21, rBlo t and rBlo t 21 proteins were 64.95, 65.98, 30.41, 41.24, 30.93 and 21.65%, respectively. The IgE reactivity of rDer f 5 correlated highly with that of rDer f 21 (r=0.733). rTyr p 5 exhibited the highest level of correlation with rTyr p 21 (r=0.950), while the correlation of rBlo t 5 with rBlo t 21 was the lowest observed (r=0.104). The binding of IgE to rDer f 5 and rDer f 21 was not inhibited by any allergens but themselves. While rDer f 5 inhibited only 60.3% of IgE binding to rBlo t 5, rDer f 21 exhibited a high inhibitory effect against rTyr p 5 (93.01%), rTyr p 21 (92.12%), rBlo t 5 (86.97%) and rBlo t 21 (70.30%), implying cross‑reactivity among mite species. The results of the present study demonstrated that the majority of the IgE reactivity to group-5 and -21 storage mite allergens is due to cross‑reaction. It is therefore imperative to develop an accurate, component‑resolved diagnosis for dust mite allergies.

Background: The storage mite, Tyrophagus putrescentiae, produces potent allergens, many of which have not been characterized. This study was undertaken to characterize the allergenicity of troponin C from T. putrescentiae., Methods: A cDNA encoding 17.7 kDa troponin C, with homology to cockroach allergen Bla g 6, was identified from T. putrescentiae-expressed sequence tags. Recombinant troponin C was expressed and IgE responses to the recombinant protein were assessed in the presence and absence of 10 mM CaCl(2). Cross-reactivity between T. putrescentiae troponin C and Bla g 6 was tested using an inhibition ELISA., Results: Recombinant T. putrescentiae troponin C shares 62.7-85.5% homology with troponin C from various arthropods. Sera from 5 of 47 subjects in our study group (10.6%) showed IgE binding to the recombinant protein. Interestingly, addition of 10 mM CaCl(2) increased the intensity of IgE binding approximately 2-fold. In an immune-inhibition ELISA with these sera, T. putrescetiae troponin C and Bla g 6 did not cross-react significantly., Conclusions: Troponin C is a new mite allergen with calcium-dependent IgE reactivity.

Cockroaches cause allergic diseases and are closely linked with the development of asthma. Bla g 1 is one of the major allergen proteins produced by German cockroaches. It consists of tandem repeats of approximately 100 amino acids. The aim of the present study was to identify linear IgE-binding epitopes of Bla g 1.02. RT-PCR was used to clone a cDNA sequence encoding Bla g 1.02 (EF202179) which shared 98.6-99.8% identity with a previously reported Bla g 1.02 (AF072220). To investigate IgE binding regions, five separate but overlapping Bla g 1.02 peptide fragments (A: aa 1-111, B: aa 102-215, C: aa 206-299, D: aa 289-403, E: aa 394-491) were amplified and cloned. The full-length and five peptide fragments were overexpressed in Pichia pastoris and E. coli, respectively, and their IgE binding reactivities were measured by ELISA using 37 serum samples isolated from cockroach-sensitized patients. The sera of 24 patients (64.9%) recognized the full-length Bla g 1.02 recombinant protein. Among 19 selected serum samples, 11 sera (57.9%) reacted to peptide fragment A, 5 sera (31.3%) to B, 4 sera (21.1%) to C, 9 sera (47.4%) to D, and 10 sera (52.6%) to peptide fragment E. IgE-binding epitopes are found to be distributed to each tandem repeat of Bla g 1. The combination of peptide fragments A, D, and E may able to detect all Bla g 1-sensitized subjects. We suggest that these peptide fragments may be useful in allergy diagnosis and the design of novel immunotherapeutics.

Background: The cockroach allergen Bla g 4, a putative lipocalin, is known to exhibit frequent sequence variations. However, the previously reported cDNA sequences are truncated at the N terminus. This study was undertaken to investigate the mechanisms by which these sequence variations are generated., Methods: Rapid amplification of cDNA ends PCR and RT-PCR were performed to obtain the full sequence of the Bla g 4 cDNA, and PCR was also used to clone the Bla g 4 genomic DNA. In addition, Bla g 4 protein variants were analyzed by two-dimensional gel electrophoresis., Results: Nine additional amino acid residues at the N terminus of Bla g 4 were identified, and 2 genes encoding Bla g 4, both of which consisted of 5 exons, were cloned. Examination of 34 clones of Bla g 4 cDNA obtained by RT-PCR revealed 14 variants. In particular, Bla g 4 sequences showed frequent clusters of variations in residues 38-45, 61-82 and 144-163. Differences in cDNA sequences may imply that RNA sequences are edited after transcription. More than 10 spots were identified between pH 5 and 7 upon two-dimensional gel electrophoresis, indicating that multiple variants of Bla g 4 are produced at the protein level., Conclusions: Genetic polymorphisms among individual cockroaches, the existence of multiple genes and sequence variations caused by RNA editing produce sequence diversity of Bla g 4, which may influence its allergenicity. The sequence information obtained in this study will be helpful for the standardization of the cockroach allergen and thereby aid in the development of diagnostics and immunotherapeutics., (Copyright 2008 S. Karger AG, Basel.)

Background: Cockroach glutathione S-transferases (GSTs) are known to elicit strong IgE responses. This study was undertaken to compare the IgE reactivity of German cockroach GSTs, Bla g 5 (sigma class) and delta class GST (BgGSTD1)., Methods: Full-length Bla g 5 and BgGSTD1 were cloned, and their recombinant proteins were expressed and purified. Their IgE reactivities and cross-reactivities were examined by ELISA using sera from cockroach-sensitized subjects., Results: A predominant variant of Bla g 5 cDNA has amino acid substitutions at positions 10 (C to F) and 42 (N to K). BgGSTD1 has substitutions at positions 27 (E to N) and 207 (K to R). Sera from cockroach-sensitized patients showed 20.5% IgE reactivity to Bla g 5 and 17.9% IgE reactivity to BgGSTD1. However, inhibition studies using 1 serum sample with the highest IgE reactivity showed limited cross-reactivity., Conclusions: IgE-binding frequency to the cockroach GSTs was low, but the titer of IgE reactivity was strong in some sera. The inclusion of different classes of GSTs could be helpful for the delicate diagnosis and immunotherapy of cockroach allergy., ((c) 2008 S. Karger AG, Basel.)

Background: The allergenicity of allergens could be influenced by amino acid substitutions in B- or T-cell epitope regions. The German cockroach is known to produce potent allergens inducing strong IgE-mediated allergic reactions. This study was performed to investigate sequence variations in major allergens of the German cockroach., Methods: Reverse transcriptase PCR was used to amplify the cDNA sequences encoding major allergens of the German cockroach (Bla g 1, Bla g 2, Bla g 4, and Bla g 5)., Results: The deduced amino acid sequences revealed 38 Bla g 1 variants with 1-7 amino acid substitutions (98.6-99.8% identity), 28 Bla g 2 variants with 1-3 substitutions (99.1-99.7%), 27 Bla g 4 variants with 0-32 substitutions (82.4-100%), and 8 Bla g 5 variants with 1-2 substitutions (99.0-99.5%), respectively. Bla g 1 and Bla g 2 showed sporadic amino acid substitutions despite the divergence in their sequences. Bla g 4 exhibited frequent variations, with clusters of substitutions in residues 29-38, 52-80, and 132-155. Sequence variations in Bla g 4 imply the presence of multiple isoforms and isoallergens, which may in turn have various effects on the IgE-binding capacity and T-cell responsiveness. Only 8 variants were found in Bla g 5, with infrequent amino acid changes of one or two residues., Conclusions: Analyses of T-cell and IgE-binding epitope regions would clarify the effect of sequence polymorphisms on allergenicity, which in turn will aid in the design of allergen formulations for diagnosis and immunotherapy for cockroach allergies., (2007 S. Karger AG, Basel)

Der f 1, a major house dust mite allergen and member of the papain-like cysteine protease family, can provoke immune responses with its proteolytic activity. To understand the role of Der f 1 in inflammatory immune responses, we studied the mechanism of the regulation of interleukin (IL)-8 expressions in human basophilic cell KU812 by proteolytically active recombinant Der f 1. Not only production of IL-8 mRNA was induced but also the DNA binding activity of activator protein-1 (AP-1) and phosphorylation of NF-κB p65 were increased in Der f 1-treated KU812. Furthermore, Der f 1 induction of IL-8 expression was sensitive to pharmacological inhibition of ERK and p38 mitogen activated protein kinase (MAPK) pathways. Der f 1 also activated ERK and p38 MAPK phosphorylation and rapidly induced reactive oxygen species (ROS) production. The antioxidant N-acetyl-cysteine (NAC) inhibited phosphorylation of ERK, but not p38, suggesting that secretion of IL-8 in KU812 cells treated with Der f 1 is dependent on ROS, ERK MAPK and p38 MAPK. We describe the mechanism of Der f 1-induced IL-8 secretion from human basophilic cells, which are thought to be important for allergic inflammation independent of IgE antibodies. These findings improve our understanding of the inflammatory immune response in human basophils to protease allergens. [ABSTRACT FROM AUTHOR]