MBD2 promotes Th2 differentiation in ovalbumin-induced CD4<sup>+</sup> T cells

Introduction: Allergen-specific CD4⁺ T cells play a central role in autoimmune disorders, allergies and asthma, with Th2-type immunity being the typical functional response of CD4⁺ T cells. This study aimed to investigate the role of MBD2 in regulating Th2 cell differentiation. Methods: Splenic mononuclear cells were extracted from C57BL/6 mice, and CD4⁺ T cells were isolated using magnetic beads and confirmed through flow cytometry. Lentivirus was employed to construct MBD2-silenced CD4⁺ T cells. In vitro experiments were performed to treat splenogenic mononuclear cells and CD4⁺ T cells with Ovalbumin (OVA), and Th2 cell ratios and IL-4 levels were assessed using flow cytometry and ELISA. Results: The purity of the isolated CD4⁺ T cells was 95.73%, confirming successful isolation of primary CD4⁺ T cells. Compared to the control group, the Th2 cell ratio exhibited an increase in the Th2-induced group. Treatment with 5-Aza (concentrations, 1–100 μM) promoted Th2 cell differentiation and increased IL-4 levels. Notably, when combined with Th2 induction and 10 μM 5-Aza treatment, silencing MBD2 further amplified Th2 cell ratios and elevated IL-4 levels in cell supernatants. Furthermore, OVA (concentration, 200 μg/mL) induced the differentiation of CD4⁺ T cells into Th2 cells and increased IL-4 secretion. Interestingly, silencing MBD2 significantly increased the Th2 cell ratio and IL-4 levels in OVA-treated CD4⁺ T cells. Conclusion: In summary, OVA promoted CD4⁺ T cell differentiation into Th2 cells and enhanced IL-4 levels. MBD2 was identified as a mediator of Th2 cell differentiation in splenic-derived CD4⁺ T cells, influenced by OVA or 5-Aza treatment.