Aedes aegypti and Dermatophagoides pteronyssinus contain important allergens including crossreactive tropomyosins. However, the functional and clinical relevance of their crossreactivity is still debated.
To analyse the humoral and cellular crossreactivity of recombinant Aed a 10.01, Aed a 10.02 and Der p 10.
Sera from 15 Austrian house dust miteallergic, Der p 10sensitized 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.
IgE antibodies of Der p 10sensitized patients crossreacted 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 10specific IgE than Aed a 10.02. Murine antibodies raised against Aed a 10.01 and Aed a 10.02 crossreacted with Der p 10. Aed a 10.01specific antibody showed stronger crossreactivity with Der p 10 than Aed a 10.02specific antibody. Splenocytes from both groups of mice proliferated similarly to all tropomyosins. Five crossreactive T cellactivating regions were identified.
Conclusion and Clinical relevance
Tropomyosins from D. pteronyssinus and A. aegypti show humoral and cellular crossreactivity, involving 5 potential T cellactivating regions. The more pronounced crossreactivity of Aed a 10.01 and Der p 10 matched the higher sequence similarity of both proteins.