Immunological cross-reactivity between olive and grass pollen: implication of major and minor allergens

Background Grasses and olive trees are the most common sources of allergenic pollen worldwide. Although they share some allergens, there are few studies analyzing the in vitro cross-reactivity between them. The aim was to define the cross-reactivity between Olea europaea and Phleum pratense using well-characterized sera of allergic children from Madrid, Spain.Methods 66 patients (mean age 10.32+/−4.07 years) were included in the study. All suffered from rhinoconjuntivitis and/or asthma and had a positive skin test and/or specific IgE determination to olive and grass pollen. Serum sIgE to individual allergens was conducted and sIgE against different grass species and olive was also determined by ELISA. Inhibition assays were performed using two serum sources, containing, or not, sIgE to minor allergens. Mass spectrometry analysis was performed in both extracts.Results 59/66 (89.39%) children had a positive sIgE determination by ELISA to grasses and 57/66 (86.36%) to olive pollen. There was no significant correlation between sIgE levels to grass and olive. Inhibition assays demonstrated no cross-reactivity between P. pratense and olive pollen when using the pool containing mainly sIgE to major allergens, whereas minimal to moderate cross-reactivity was detected when the serum contained high sIgE titers to minor allergens. Proteomic analyses revealed the presence of 42 common proteins in grasses and olive pollens.Conclusion No in vitro cross-reactivity was observed when sIgE was mainly directed to major allergens. In our population, sensitization to olive and grasses is not due to cross-reactivity. The contribution of the major allergens seems to be determinant. Keywords: Cross-reactivity, Minor allergens, Olea europaea, Panallergen, Phleum pratense, Polle

Environmental control of mite allergy

ESCOLA PAULISTA MED,DEPT PEDIAT,DIV RHEUMATOL ALLERGY & CLIN IMMUNOL,SAO PAULO,BRAZILESCOLA PAULISTA MED,DEPT PEDIAT,DIV RHEUMATOL ALLERGY & CLIN IMMUNOL,SAO PAULO,BRAZILWeb of Scienc

Clinical & Experimental Allergy / Tropomyosins in mosquito and house dust mite crossreact at the humoral and cellular level

Background Aedes aegypti and Dermatophagoides pteronyssinus contain important allergens including crossreactive tropomyosins. However, the functional and clinical relevance of their crossreactivity is still debated. Objective To analyse the humoral and cellular crossreactivity of recombinant Aed a 10.01, Aed a 10.02 and Der p 10. Methods 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. Results 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.(VLID)339840