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

Authors: Mattison, Chris; KHURANA, TARUNA - Food And Drug Administration(FDA); TARVER, MATTHEW - Bayer Cropscience; Florane, Christopher; Grimm, Casey; PAKALA, SUMAN - University Of Georgia; COTTONE, CARRIE - New Orleans Mosquito, Termite & Rodent Control Board; RIEGEL, CLAUDIA - New Orleans Mosquito, Termite & Rodent Control Board; BREN-MATTISON, YVETTE - Biomed Bridge; SLATER, JAY - Food And Drug Administration(FDA)

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2017
Publication Date: 8/2/2017
Citation: Mattison, C.P., Khurana, T., Tarver, M.R., Florane, C.B., Grimm, C.C., Pakala, S., Cottone, C.B., Riegel, C., Bren-Mattison, Y., Slater, J.E. 2017. Cross-reaction between Formosan termite (Coptotermes formosanus) proteins and cockroach allergens. PLoS One. 12(8):e0182260. https://doi.org/10.1371/journal.pone.0182260.
DOI: https://doi.org/10.1371/journal.pone.0182260

Interpretive Summary: Edible insects, such as cockroaches and termites, are beginning to be popularized as an alternate source of protein and have high nutritional value. Identification of cross-reactivity between commonly consumed food proteins and edible insects is important for food safety and to enable improvements in allergy diagnosis and therapy. Shrimp are among a group of 8 foods that commonly cause food allergy. Shrimp allergens can be recognized by human IgE to cockroach allergens. This cross-reaction, or recognition of similar proteins by IgE, can complicate diagnostic and therapeutic allergy strategies. Termites are evolutionarily very similar to cockroaches. The Formosan subterranean termite Coptotermes formosanus (C.f.) is one of the most common species in the southern United States. We characterized similarities between cockroach allergens and termite proteins by analyzing gene and protein sequences. Gene and protein sequencing results indicate there are important similarities between predicted termite proteins and German and American cockroach allergens. Antibody and human serum IgE testing indicates there are significant cross-reactions between termite proteins and cockroach allergens. This research likely has important consequences in the food and airborne allergy field, especially for those areas where human dwellings are infested by termites. Continued work is necessary to better characterize termite proteins as potential allergens.

Technical Abstract: Edible insects, such as cockroaches and termites, are beginning to be popularized as an alternate source of protein and have high nutritional value. Identification of cross-reactivity between commonly consumed food proteins and edible insects is important for food safety and to enable improvements in allergy diagnosis and therapy. Crustacean shellfish are included in a group of 8 foods that commonly cause food allergy, and shellfish allergens have been demonstrated to cross-react with arthropod proteins, such as those from cockroaches. Allergy to cockroach is a significant problem in urban areas infested with the insects. Inhaled cockroach allergens can lead to serious asthma symptoms and even hospitalization. Termites are evolutionarily related to cockroaches, co-habitate in human dwellings, and represent an increasing pest problem in the United States. The Formosan subterranean termite Coptotermes formosanus (C.f.) is one of the most common species in the southern United States. Due to the evolutionary relationship between the two insects, we sought to determine if C.f. termite proteins cross-react with cockroach allergens. We identify significant homology between termite proteins and cockroach allergens using BLAST 2.2.21 software. Sequencing results indicate greater than 60% homology between predicted termite proteins and German and American cockroach allergens, including Bla g 3/Per a 3, Bla g 6/Per a 6, Bla g 7/Per a 7, Bla g 8, and Per a 9. Whole termite extracts were analyzed by mass-spectrometry, and 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. Immunoassays with IgG and scFv antibodies to cockroach allergens, and human IgE from serum samples of cockroach allergic patients revealed cross-reaction between several proteins with IgG and IgE antibodies to cockroach allergens. In particular, anti-cockroach allergen antibodies were reactive to putative termite homologs of hemocyanin (Bla g 3) and tropomyosin (Bla g 7). We have demonstrated that several termite proteins, including the hemocyanin and tropomyosin orthologs, cross-react with cockroach allergens. This research may have important consequences in the allergy field, especially for those areas where human dwellings are infested by termites. Continued work is warranted to more carefully characterize allergen cross-reacting termite proteins and determine their clinical significance to food and airborne allergies.