A novel tool for the detection of allergic sensitization combining protein microarrays with human basophils

Protein microarray (PM) is a powerful alternative to costly or labour-intensive diagnostic for the large-scale detection of allergen-specific IgE. In this study, we established a proof-of-concept that coupling the diversity of protein array with the biological output of basophilic cells is a feasible proposition.

Human basophils purified from the peripheral blood of healthy donors were stripped, re-sensitized with the serum or IgE preparation to be tested, and incubated with manually spotted protein array chips (FAST slides). The basophilic cell lines KU-812 and RBL-703/21 likewise sensitized were compared with peripheral blood basophils by the same approach. Purified basophils or other basophilic cells were incubated with FAST slides for various periods of time, washed, and cell binding was visualized by light microscopy. Basophil activation, indicating the effective cross-linking of IgE by allergens, was monitored via up-regulation of basophil activation surface marker (CD 63).

Purified stripped peripheral basophils, re-sensitized with the serum of a grass pollen-allergic patient, displayed strong binding to anti-IgE antibody and grass pollen extract with relatively low unspecific binding. Similar results were obtained with RBL-703/21, which may be a good replacement for peripheral basophils to avoid the costly, cumbersome and time-consuming basophil purification.

Our data suggest that coupling the diversity of a PM approach with the potential functionality and biological activity of a cell-based test is feasible and may result in a new system to detect allergic sensitization.