Tropomyosins in mosquito and house dust mite cross‐react at the humoral and cellular level

Summary Background Aedes aegypti and Dermatophagoides pteronyssinus contain important allergens including cross‐reactive tropomyosins. However, the functional and clinical relevance of their cross‐reactivity is still debated. Objective To analyse the humoral and cellular cross‐reactivity of recombinant Aed a 10.01, Aed a 10.02 and Der p 10. Methods Sera from 15 Austrian house dust mite‐allergic, Der p 10‐sensitized individuals were tested for IgE reactivity to recombinant tropomyosins in ELISA, inhibition ELISA and basophil activation tests. BALB/c mice were immunized with Aed a 10.01 or Aed a 10.02, and their sera were assessed for reactivity to all tropomyosins. Splenocytes were stimulated with all tropomyosins and synthetic peptides representing the amino acid sequence of Aed a 10.01. Results IgE antibodies of Der p 10‐sensitized patients cross‐reacted with both tropomyosins from A. aegypti. Aed a 10.01 was a more potent inhibitor of IgE binding to Der p 10 and a stronger activator of basophils sensitized with Der p 10‐specific IgE than Aed a 10.02. Murine antibodies raised against Aed a 10.01 and Aed a 10.02 cross‐reacted with Der p 10. Aed a 10.01‐specific antibody showed stronger cross‐reactivity with Der p 10 than Aed a 10.02‐specific antibody. Splenocytes from both groups of mice proliferated similarly to all tropomyosins. Five cross‐reactive T cell‐activating regions were identified. Conclusion and Clinical relevance Tropomyosins from D. pteronyssinus and A. aegypti show humoral and cellular cross‐reactivity, involving 5 potential T cell‐activating regions. The more pronounced cross‐reactivity of Aed a 10.01 and Der p 10 matched the higher sequence similarity of both proteins.