Identification of the pan-allergen tropomyosin from the common bed bug (Cimex lectularius)

Tropomyosin is a muscle contraction protein documented across all animal life. Despite its ubiquity, its unique structure in invertebrates leads to allergic responses in humans that vertebrate tropomyosin does not. High degrees of homology can explain cross-reactivity between tropomyosin derived from distantly-related arthropod species and establishes tropomyosin as a panallergen. Given this cross-reactivity and that they are commonly found in high numbers indoors, research on the potential of the common bed bug (Cimex lectularius L.) to contribute tropomyosin to the indoor environment is needed. Therefore, we investigated tropomyosin homology between bed bugs and known tropomyosin allergens from other taxa, tropomyosin in bed bug bodies, feces, and exuviae (cast skins), tropomyosin persistence over time, and impacts of common bed bug treatment strategies on detectable tropomyosin. Tropomyosin was detected in mechanically fractured bed bug cadavers and was detectable in bed bugs cadavers aged for 18 months. Additionally, a survey of pest management professionals showed dead bed bugs are not cleaned up following treatment. As such, dead bed bugs could act as tropomyosin reservoirs following bed bug treatment and exposure to tropomyosin from bed bugs could sensitize individuals and lead to increased responses to other arthropod tropomyosin.