ABSTRACT Background Amoxicillin (AX) is frequently implicated in immediate IgE‐mediated allergic reactions. Diagnosis is challenging, highlighting the need for new approaches enhancing in vitro sensitivity and specificity. Engineered nanostructures can mimic immunological recognition of hapten‐carrier conjugates, offering a strategy to improve diagnostic accuracy. Methods Dendrimeric Antigens (DeAns), with controlled size (1st–5th generation) and multivalent AX determinants (8–128 units, respectively), were synthesized for in vitro immunological evaluation. In vitro IgE recognition was studied by competitive radio‐immunoassay. Allergenic activity was evaluated in mouse bone marrow‐derived mast cells (MC) sensitized with mouse anti‐AX IgE monoclonal antibody and humanized RBL‐2H3 (huRBL‐2H3) and LUVA cells sensitized with sera from β‐lactam‐allergic subjects and tolerant controls, measuring degranulation in response to DeAns stimulation. Results Five different DeAns were obtained as pure compounds. All DeAns were recognized by AX‐sIgE. A clear size‐dependent activation pattern was observed in the three cell models: lower‐generation (1st–2nd) DeAns failed to induce degranulation, whereas DeAns of bigger size (3rd–5th generation) triggered significant, dose‐dependent activation. Notably, no activation was observed in tolerants and unsensitized cells or with blank dendrimers. In patient‐sera assays, the passive MC activation test (pMAT) with DeAns provided complete diagnostic discrimination, with activation restricted to AX‐allergic patients. Conclusions DeAns are effective platforms for investigating effector cell activation in AX allergy. By fine‐tuning structural attributes—size and multivalence—we reveal the promising utility of DeAns in pMAT that leverage commercial cell lines and patient sera. This approach could address key limitations of β‐lactam allergy diagnostics, enabling more reliable and standardized in vitro testing.
Ayane et al. (Wed,) studied this question.