RT Journal Article T1 Dendrimeric antigens for passive mast cell activation in the evaluation of amoxicillin allergy A1 Tesfaye Ayane, Amene A1 Salas, María A1 Benede, Sara A1 Rodríguez-Sánchez, Maria J. A1 Rodríguez-Sojo, María J. A1 Jiménez-Sánchez, Isabel M. A1 Bogas, Gador A1 Pérez-de-Inestrosa-Villatoro, Ezequiel A1 Mayorga, Cristobalina A1 Paris, Juan L. A1 Rodríguez-Nogales, Alba A1 Torres-Jaén, María Josefa A1 Montañez-Vega, María Isabel K1 Antibióticos K1 Alergia a los medicamentos K1 Antibióticos betalactámicos K1 Amoxicilina AB 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 mimicimmunological 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 com-petitive radio-immunoassay. Allergenic activity was evaluated in mouse bone marrow-derived mast cells (MC) sensitized withmouse anti-AX IgE monoclonal antibody and humanized RBL-2H3 (huRBL-2H3) and LUVA cells sensitized with sera fromβ-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 degranu-lation, whereas DeAns of bigger size (3rd–5th generation) triggered significant, dose-dependent activation. Notably, no activationwas 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 structuralattributes—size and multivalence—we reveal the promising utility of DeAns in pMAT that leverage commercial cell lines andpatient sera. This approach could address key limitations of β-lactam allergy diagnostics, enabling more reliable and standard-ized in vitro testing. PB Wiley YR 2026 FD 2026 LK https://hdl.handle.net/10630/45417 UL https://hdl.handle.net/10630/45417 LA eng NO A. T. Ayane, M. Salas, S. Benede, et al., “ Dendrimeric Antigens for Passive Mast Cell Activation in the Evaluation of Amoxicillin Allergy,” Allergy (2026): 1–12, https://doi.org/10.1111/all.70250. NO Funding for open access charge: Universidad de Málaga / CBUA DS RIUMA. Repositorio Institucional de la Universidad de Málaga RD 20 mar 2026