Cross-reaction between Formosan termite (Coptotermes formosanus) proteins and cockroach allergens

PLoS One. 2017 Aug 2;12(8):e0182260. doi: 10.1371/journal.pone.0182260. eCollection 2017.

Abstract

Cockroach allergens can lead to serious allergy and asthma symptoms. Termites are evolutionarily related to cockroaches, cohabitate in human dwellings, and represent an increasing pest problem in the United States. The Formosan subterranean termite (Coptotermes formosanus) is one of the most common species in the southern United States. Several assays were used to determine if C. formosanus termite proteins cross-react with cockroach allergens. Expressed sequence tag and genomic sequencing results were searched for homology to cockroach allergens using BLAST 2.2.21 software. Whole termite extracts were analyzed by mass-spectrometry, immunoassay with IgG and scFv antibodies to cockroach allergens, and human IgE from serum samples of cockroach allergic patients. Expressed sequence tag and genomic sequencing results indicate greater than 60% similarity between predicted termite proteins and German and American cockroach allergens, including Bla g 2/Per a 2, Bla g 3/Per a 3, Bla g 5, Bla g 6/Per a 6, Bla g 7/Per a 7, Bla g 8, Per a 9, and Per a 10. Peptides from whole termite extract were matched to those of the tropomyosin (Bla g 7), arginine kinase (Per a 9), and myosin (Bla g 8) cockroach allergens by mass-spectrometry. Immunoblot and ELISA testing revealed cross-reaction between several proteins with IgG and IgE antibodies to cockroach allergens. Several termite proteins, including the hemocyanin and tropomyosin orthologs of Blag 3 and Bla g 7, were shown to crossreact with cockroach allergens. This work presents support for the hypothesis that termite proteins may act as allergens and the findings could be applied to future allergen characterization, epitope analysis, and clinical studies.

MeSH terms

  • Allergens / genetics
  • Allergens / immunology*
  • Animals
  • Cockroaches / genetics
  • Cockroaches / immunology*
  • Cross Reactions
  • Immunoglobulin A / metabolism
  • Immunoglobulin E / metabolism
  • Immunoglobulins / metabolism*
  • Insect Proteins / genetics
  • Insect Proteins / immunology
  • Isoptera / genetics
  • Isoptera / immunology*
  • Sequence Homology, Nucleic Acid
  • United States

Substances

  • Allergens
  • Immunoglobulin A
  • Immunoglobulins
  • Insect Proteins
  • Immunoglobulin E

Grants and funding

This research was supported by funds from the U.S. Department of Agriculture−Agricultural Research Service and intramural funding from the Center for Biologics Evaluation and Research, FDA. The funders (Bayer CropScience and BioMed Bridge, LLC) have provided support in the form of salaries for authors [MRT, YBM], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. Mention of trade names, commercial products, or companies in this paper is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.