Allergen immunotherapy (AIT) is currently the only disease-modifying treatment forallergies. Pre-clinical models for the evaluation of novel therapeutics are crucial forensuring their efficacy and safety. While cell culture models are cost-effective andefficient, they cannot fully replicate the cellular interactions in vivo. Therefore, it isessential to use more sophisticated model systems, such as co-cultures, to assess thepotential of new therapeutics more accurately. Immunomodulatory protein banana lectin(BLwt) is an attractive candidate for adjuvant in AIT. Its mutant BLH84T was developed toreduce its potential mitogenicity. The aim of this study was the development of the coculture model system for testing the immunomodulatory effect of chimeras composed ofthe major birch pollen allergen (Bv1a) and BLwt (Bv1a-BLwt, Cwt), the hypoallergenicisoform of Bv1a (Bv1l) and BLH84T (Bv1l-BLH84T, C1 and BLH84T-Bv1l, C2). Chimericstructures were designed in silico, fully minimized, and relaxed without van der Waalsatomic clashes. Afterward, proteins were successfully expressed in Escherichia coli andpurified by IMAC yielding around 0.4 mg per 1L of expression medium. The IgE bindingcapacity was assessed using ELISA inhibition with birch pollen allergic patients’ sera.Caco-2 intestinal epithelial cells and THP-1 differentiated macrophages were used for theco-culture model system development. After protein application on the apical side of theco-culture, the integrity of the epithelial monolayer was not disturbed. Theimmunomodulatory potential of antigens was tested by measuring the gene expressionlevels for pro- and anti-inflammatory cytokines in both cell lines from co-culture. Theobtained results indicate that the best anti-inflammatory response was favored aftertreatment with Cwt. Additionally, to further confirm the immunomodulatory effect of therecombinant chimeras, PBMCs obtained from individuals allergic to birch pollen wereemployed and treated with recombinant proteins. Only after treatment with Cwt, PBMCssecreted the anti-inflammatory cytokine IL-10. Obtained results suggest that Cwt chimeracould have a therapeutic effect in AIT in birch pollen allergy
