D3.214 - A multi-epitope protein promotes regulatory T-cell responses in PBLs from HDM-allergic patients

Allergic diseases in tropical regions are strongly associated with sensitization to house dust mites (HDM) and helminths such as Ascaris lumbricoides. T-cell epitope–based strategies may promote immune regulation while reducing IgE-mediated allergenicity, representing a safer alternative to conventional allergen-specific immunotherapy. This study aimed to evaluate CD4⁺ T-cell proliferation and regulatory T-cell (Treg) induction following stimulation with the recombinant T-cell multi-epitope protein (TcMe) in PBL from HDM-allergic patients.

The TcMe protein was designed using an immunoinformatic pipeline. Peripheral blood leukocyte cells from six HDM-allergic asthmatic patients and non-allergic controls were isolated and labeled with CFSE for proliferation assays. Cells were stimulated with TcMe protein, whole D. pteronyssinus  or RPMI (negative control). After 6 days, CD3⁺CD4⁺, and CD4⁺CD25⁺FoxP3⁺ T-cells proliferation was assessed by flow cytometry. Statistical comparisons were performed using repeated-measures analysis (p<0.05).

TcMe induced a dose-dependent increase in CD3⁺CD4⁺ T-cell proliferation compared to unstimulated PBL (p<0.05), reaching levels comparable to those induced by whole D. pteronyssinus extract (Fig. A). Importantly, TcMe significantly increased the proportion of CD4⁺CD25⁺FoxP3⁺ Treg cells compared to RPMI (p<0.05), whereas whole D. pteronyssinus extract did not induce a comparable expansion of Treg populations (Fig. B). No significant changes were observed in PBMC from non-allergic controls.

TcMe exhibits  T-cell immunogenicity while preferentially promoting regulatory T-cell expansion in PBL  from HDM-allergic patients, showing a potential immunomodulatory effect on allergic patients’  T cells.