H2-Eb1, the mouse ortholog of human HLA-DRB1, is likely involved in antigen-presentation as it is a MHC class II related gene. MHC class II molecules play a crucial role in the adaptive immune response by presenting extracellular antigens to CD4+ T-cells, thus participating in immune regulation pathways [3,4,5,6]. Genetic models, such as knockout mice, are valuable for studying its function.

In allergic rhinitis (AR) studies, H2-Eb1 knockout mouse models have provided key insights. Knockout of the H2-Eb1 gene alleviated AR symptoms in mice. In H2-Eb1 knockout mice, compared to the control group, the serum OVA-IgE and IL-4 levels significantly increased, while IFN-γ levels significantly dropped. Also, homozygous (-/-) knockout mice had lower serum OVA-IgE and IL-4 levels, higher IFN-γ levels, and slighter allergic symptoms than heterozygous (+/-) counterparts, indicating that H2-Eb1 may play an important role in regulating Th1/Th2 balance during AR pathogenesis [1]. Moreover, double knockout of H2-Eb1 and H2-Ab1 in mice led to reduced susceptibility to AR, with fewer histological changes in nasal mucosal tissue, reduced numbers of eosinophilic granulocytes and mast cells, and altered cytokine levels [2].

In conclusion, H2-Eb1 is important in the context of immune-related processes, especially in the regulation of Th1/Th2 balance. The study of H2-Eb1 knockout mouse models has significantly contributed to our understanding of its role in allergic rhinitis, providing a basis for further exploration of the disease mechanism and potential therapeutic strategies.